hovedoppgave - Department of Computer and Information Science

Transcription

NORGES TEKNISK-NATURVITENSKAPELIGE UNIVERSITET
FAKULTET FOR FYSIKK , INFORMATIKK OG MATEMATIKK
HOVEDOPPGAVE
Kandidatens navn:
Jon Arvid Børretzen
Fag:
Datateknikk
Oppgavens tittel (norsk):
Utprøving av forskjellige multimedia klientteknologier på mobilt
utstyr
Oppgavens tittel (engelsk):
A survey of multimedia client technologies on mobile devices
Oppgavens tekst:
Oppgaven går ut på å prøve forskjellige klientteknologier på mobilt utstyr for å se på
utfordringer/begrensninger med denne type teknologier. Det er spesielt interessant å se på
overføring/presentasjon av multimedia fra/til mobilt utstyr. Det kan eksempelvis være digital
videooveføring vha. mobiltelefoner (GPRS), streaming av MP3/MPEG til mobiltelefoner/PDA.
Oppgaven gitt:
20. januar 2002
Besvarelsen leveres innen:
17. juni 2002
Besvarelsen levert:
14. juni 2002
Utført ved:
Institutt for datateknikk og informasjonsvitenskap
Veiledere:
Alf Inge Wang
Trondheim, 14. juni 2002
Faglærer
A survey of multimedia
client technologies
on mobile devices
Jon Arvid
Børretzen
A survey of multimedia technologies on mobile devices
ABSTRACT
Abstract
As mobile devices are getting increasingly more popular, and with the expanding ranges of
application for this technology, there is a need to explore the possibilities and limitations of
such technology. MOWAHS, a project at IDI, NTNU, is working with mobile work across
heterogeneous systems, where mobile computers could become an important part of that
heterogeneous environment in the future.
This thesis aims to evaluate different aspects of multimedia issues for mobile computing.
Mobile devices, network technology and some applications will be presented and compared.
The different client technologies for mobile equipment will be presented in order to discover
some of the challenges and restrictions with these kinds of technology. Especially the
transmission and presentation aspect of multimedia to and from mobile equipment is in
focus. The technologies available today and in the near future are then evaluated.
This is therefore an exploration into the sort of technology the MOWAHS project will have to
deal with when concerned with mobile multimedia issues.
Key words
Multimedia, mobile devices, wireless networks, mobile phones, PDA
v
PREFACE
Preface
This thesis is the work done by Jon Arvid Børretzen at IDI – Department of computer and
information science and NTNU – Norwegian University of Science and Technology, during
the spring of 2002.
Firstly, I would like to thank my teaching supervisor Alf Inge Wang for valuable guidance, a
lot of good input, and very good collaboration during the writing of this thesis. Secondly, I
want to thank co-students Jørgen Austvik and Per Håkon Meland for providing me with
helpful tips and useful media files.
Furthermore, I would like to thank everyone that has been around for the last five months for
the good discussions on the subject I have been researching.
Finally I want to thank NTNU and the city of Trondheim for taking care of me for five of the
best years in my life.
_______________________
Jon Arvid Børretzen,
Trondheim, June 14, 2002
vii
INDEX
Index
Part I - Introduction ................................................................................... 1
Chapter 1 – Introduction of the thesis .........................................................................3
1.1 Structure of report......................................................................................................3
1.2 Research agenda.......................................................................................................3
1.3 Context for thesis .......................................................................................................3
1.3.1 MOWAHS ............................................................................................................... 3
1.3.2 MOWAHS Background .......................................................................................... 4
1.3.3 Mobility.................................................................................................................... 5
1.3.4 Multimedia .............................................................................................................. 5
1.3.5 Media types ............................................................................................................ 6
1.3.6 Multimedia applications .......................................................................................... 7
1.4 The problem definition...............................................................................................7
1.5 Motivation....................................................................................................................7
1.6 Goals ............................................................................................................................7
1.7 Readers Guide ...........................................................................................................7
Part II - Prestudy........................................................................................ 9
Chapter 2 – Client technology......................................................................................13
2.1 Portable/mobile devices..........................................................................................13
2.1.1 Laptop computers................................................................................................. 13
2.1.2 Personal Digital Assistants................................................................................... 14
2.1.3 Mobile phones ...................................................................................................... 15
2.1.4 Other types of portable units ................................................................................ 16
2.2 Alternative classification .........................................................................................16
2.2.1 Operating systems for portable devices .............................................................. 17
2.2.2 EPOC (Symbian).................................................................................................. 18
2.2.3 PalmOS (Palm).................................................................................................... 18
2.2.4 Pocket PC (Microsoft) .......................................................................................... 19
2.3 Development and application environment for portable devices .....................21
2.3.1 J2ME ..................................................................................................................... 21
2.3.2 CLDC.................................................................................................................... 21
2.3.3 MIDP..................................................................................................................... 21
2.4 Examples of portable devices ................................................................................22
2.4.1 Laptop: Dell Inspiron 2650 ................................................................................... 22
2.4.2 Pocket PC PDA: Compaq iPAQ 3850H Pocket PC ............................................ 23
2.4.3 Pocket PC PDA: Casio E-200 CASSIOPEIA Pocket PC 2002 ........................... 23
2.4.4 Linux PDA: Sharp Zaurus 5000D......................................................................... 24
2.4.5 Palm PDA: Palm m515 ........................................................................................ 24
2.4.6 Palm PDA: Sony Cliè PEG-T615C ...................................................................... 24
2.4.7 Mobile phone: Nokia 7650 ................................................................................... 25
2.4.8 Mobile phone: Sony Ericsson T68i ...................................................................... 25
2.4.9 Mobile phone: Siemens SL45i ............................................................................. 25
2.4.10 Mobile phone: Motorola accompli008 ................................................................ 26
2.5 Comparison elements .............................................................................................26
Chapter 3 – Media player applications.......................................................................27
3.1 Media Players ...........................................................................................................27
3.2 Windows Media Player ...........................................................................................27
ix
INDEX
3.3 RealOne Player........................................................................................................28
3.4 QuickTime .................................................................................................................28
3.5 PacketVideo PVPlayer ............................................................................................28
3.6 IceStream ..................................................................................................................29
3.7 Pocket DivX ..............................................................................................................30
3.8 PocketTV ...................................................................................................................30
3.9 PhotoSuite .................................................................................................................30
3.10 Other Media player applications ..........................................................................31
Chapter 4 – Network technologies..............................................................................32
4.1 WWAN, WLAN, WPAN ...........................................................................................32
4.2 Mobile networks (WWAN) ......................................................................................33
4.3 Second generation mobile networks.....................................................................35
4.3.1 Global System for Mobile Communications (GSM) ............................................. 35
4.3.2 TDMA.................................................................................................................... 36
4.3.3 CDMA ................................................................................................................... 36
4.3.4 PDC ...................................................................................................................... 36
4.3.5 Short Message Service (SMS)............................................................................. 37
4.3.6 WAP...................................................................................................................... 37
4.3.7 High Speed Circuit Switched Data (HSCSD) ...................................................... 38
4.4 2,5G - Evolved second generation mobile networks..........................................38
4.4.1 General Packet Radio Service (GPRS)............................................................... 38
4.4.2 MMS (Multimedia Messaging Service) ................................................................ 41
4.4.3 i-Mode................................................................................................................... 41
4.5 3G – Third generation mobile networks ...............................................................41
4.5.1 EDGE.................................................................................................................... 43
4.5.2 UMTS.................................................................................................................... 43
4.5.3 cdma2000............................................................................................................. 44
4.6 Wireless network technologies (WLAN & WPAN) ..............................................45
4.6.1 The 802.11 series................................................................................................. 45
4.6.2 The HiperLAN technologies ................................................................................. 47
4.6.3 Bluetooth .............................................................................................................. 47
4.6.4 The WLAN standard muddle................................................................................ 48
4.6.5 Interworking WLANs and WWANs ...................................................................... 48
4.7 Network summary....................................................................................................50
Chapter 5 – Media architectures ..................................................................................51
5.1 Codecs and file formats ..........................................................................................51
5.2 Media Formats..........................................................................................................51
5.2.1 MPEG formats ...................................................................................................... 51
5.2.2 RealPlayer ............................................................................................................ 53
5.2.3 QuickTime ............................................................................................................ 53
5.2.4 Microsoft’s Window media files ............................................................................ 54
5.2.5 DivX...................................................................................................................... 55
5.2.6 Other media formats............................................................................................. 55
5.3 Media content and interface languages ...............................................................56
5.3.1 SGML .................................................................................................................... 56
5.3.2 HTML .................................................................................................................... 56
5.3.3 XML ...................................................................................................................... 56
5.3.4 WML ..................................................................................................................... 56
5.3.5 SMIL ..................................................................................................................... 56
5.4 Multimedia Messaging Service (MMS).................................................................57
x
INDEX
Chapter 6 – Streaming ....................................................................................................58
6.1 Streaming ..................................................................................................................58
6.2 Pseudo-streaming ....................................................................................................59
6.3 Streaming media players ........................................................................................59
6.4 Streaming infrastructure .........................................................................................60
6.5 Streaming software..................................................................................................60
6.6 Buffering ....................................................................................................................60
6.7 Compression.............................................................................................................60
6.8 Quality of Service.....................................................................................................61
6.9 Multiple Bit Rate Encoding .....................................................................................62
Chapter 7 – Market issues .............................................................................................63
7.1 Hardware demands .................................................................................................63
7.2 Network demands ....................................................................................................64
7.3 Market demands ......................................................................................................64
7.4 Video Services Today and Tomorrow ..................................................................65
Chapter 8 – Multimedia scenarios...............................................................................67
8.1 Scenario classes ......................................................................................................67
8.1.1 Video Conferences............................................................................................... 67
8.1.2 Instruction ............................................................................................................. 68
8.1.3 Surveillance.......................................................................................................... 68
8.1.4 Entertainment ....................................................................................................... 69
8.1.5 Advertising ............................................................................................................ 69
8.1.6 Information Services............................................................................................. 69
8.1.7 Location Oriented services................................................................................... 70
8.1.8 Data Transfer........................................................................................................ 70
8.2 Scenario summary...................................................................................................70
Chapter 9 – The state-of-the-art in today’s situation .............................................71
Chapter 10 – Related work ............................................................................................72
10.1 Comparison to this thesis .....................................................................................73
Part III – My contribution........................................................................75
Chapter 11 – Challenges................................................................................................77
11.1 Processing limitations ...........................................................................................77
11.2 Network limits .........................................................................................................77
11.2.1 Example: GPRS limitations ................................................................................ 78
11.2.2 Mobile networks as IP networks ........................................................................ 79
11.2.3 Network availability............................................................................................. 79
11.2.4 Network diversity ................................................................................................ 80
11.2.5 Lack of Quality of Service .................................................................................. 80
11.3 Economic climate ...................................................................................................80
11.4 What comes first, the new technology or the new services?..........................81
11.5 Mobile content – more important than the terms WLAN and UMTS .............81
11.5.1 A possible scenario ............................................................................................ 81
11.5.2 Delivery challenges ............................................................................................ 82
Chapter 12 – Solutions ...................................................................................................83
12.1 “Time and money” ..................................................................................................83
12.2 Improved client devices ........................................................................................83
12.3 More advanced networks .....................................................................................83
12.4 Interworking of networks.......................................................................................84
xi
INDEX
12.5 IPv6 ..........................................................................................................................84
Chapter 13 – Evaluation .................................................................................................85
13.1 Evaluation of device hardware ............................................................................85
13.1.1 Laptops ............................................................................................................... 86
13.1.2 PDAs ................................................................................................................... 87
13.1.3 Mobile phones .................................................................................................... 88
13.1.4 Summary and evaluation of mobile devices ...................................................... 90
13.2 Evaluation of network types .................................................................................91
13.2.1 UMTS.................................................................................................................. 92
13.2.2 EDGE.................................................................................................................. 92
13.2.3 GPRS.................................................................................................................. 93
13.2.4 GSM (with HSCSD)............................................................................................ 93
13.2.5 IEEE 802.11b ..................................................................................................... 94
13.2.6 IEEE 802.11a ..................................................................................................... 94
13.2.7 HiperLAN 2 ......................................................................................................... 94
13.2.8 Bluetooth ............................................................................................................ 95
13.2.9 Network summary and evaluation (WLANs + WPAN) ...................................... 95
13.2.10 Network summary and evaluation (WWANs) .................................................. 96
13.3 Evaluation of media technology ..........................................................................98
13.3.1 Windows media player ....................................................................................... 98
13.3.2 RealOne Player .................................................................................................. 99
13.3.3 PocketTV ............................................................................................................ 99
13.3.4 Pocket DivX...................................................................................................... 100
13.3.5 PVPlayer........................................................................................................... 101
13.3.6 IceStream ......................................................................................................... 101
13.3.7 Conditions for trials........................................................................................... 102
13.3.8 Summary of media playing applications .......................................................... 102
13.3.9 General evaluation of media playing on portable unit ..................................... 103
Chapter 14 – A glance at MMS .................................................................................. 105
Part IV – Future Visions........................................................................109
Chapter 15 - Future....................................................................................................... 111
15.1 How long will today’s technologies last? ......................................................... 111
15.1.1 Mobile networks ............................................................................................... 111
15.1.2 Other wireless networks................................................................................... 111
15.2 Hardware technology under development ...................................................... 112
15.2.1 Smartphones .................................................................................................... 112
15.2.2 Power consumption.......................................................................................... 112
15.2.3 Processing capability ....................................................................................... 112
15.2.4 Unit display....................................................................................................... 112
15.2.5 Miniaturisation .................................................................................................. 112
15.2.6 Technology integration ..................................................................................... 113
15.2.7 Operating systems ........................................................................................... 113
15.3 Network Technology in development .............................................................. 115
15.3.1 EDGE and UMTS ............................................................................................. 115
15.3.2 4G ..................................................................................................................... 115
15.3.3 HiperLAN .......................................................................................................... 116
15.4 Evolution of the service environment .............................................................. 116
15.5 Summary.............................................................................................................. 117
xii
INDEX
Part V – Summary & Conclusions ......................................................119
Chapter 16 – Summary ................................................................................................ 121
16.1 Summary of current situation............................................................................ 121
16.2 Summary of this thesis ...................................................................................... 121
Chapter 17 – Conclusion and further work............................................................ 122
17.1 Conclusion........................................................................................................... 122
17.2 Further work......................................................................................................... 122
Part VI – Appendices ............................................................................123
xiii
LIST OF TABLES
List of tables
Table 1 - Important acronyms .................................................................................................... 8
Table 2 - Hardware equipment backing for the three most important mobile operating
systems ............................................................................................................................. 18
Table 3 - Overview of mobile operating systems..................................................................... 20
Table 4 - Data Rate for GPRS ................................................................................................. 40
Table 5 - Custom bit rate encoding vs. MBR ........................................................................... 62
Table 6 - Data Rate for GPRS ................................................................................................. 78
Table 7 - Hardware evaluation criteria ..................................................................................... 86
Table 8 - Summary of mobile devices...................................................................................... 90
Table 9 - Terms for Table 8...................................................................................................... 90
Table 10 - Evaluation of mobile devices .................................................................................. 91
Table 11 - Network types to be evaluated ............................................................................... 91
Table 12 - Criteria for network evaluation ................................................................................ 92
Table 13 – Summary of WLANs + WPAN ............................................................................... 95
Table 14 - Evaluation of WLANs + WPAN............................................................................... 96
Table 15 - Summary of mobile networks ................................................................................. 96
Table 16 - Evaluation of mobile networks ................................................................................ 97
Table 17 - Properties of Media players.................................................................................. 103
Table 18 - PalmOS 4 vs. PalmOS 5 ...................................................................................... 114
xiv
LIST OF FIGURES
List of figures
Figure 1 - The MOWAHS “mascot"..........................................................................................3
Figure 2 – Laptop computer from Dell ...................................................................................13
Figure 3 - Sony VAIO C1 Picturebook....................................................................................13
Figure 4 - HP Jornada 720......................................................................................................13
Figure 5 - Apple Newton.........................................................................................................14
Figure 6 - Palm pilot 5000.......................................................................................................14
Figure 7 - Handspring Visor Prism..........................................................................................14
Figure 8 - An old Nokia mobile phone....................................................................................15
Figure 9 - Nokia 3210.............................................................................................................15
Figure 10 - Siemens SL45i.....................................................................................................15
Figure 11 - Psion Revo, Ericsson R380, Nokia 9210 and Handspring Visor Phone..............16
Figure 12 - Dell Inspiron 2650.................................................................................................20
Figure 13 - Compaq iPAQ 3850H...........................................................................................23
Figure 14 - Casio E-200 Cassiopeia.......................................................................................23
Figure 15 - Sharp Zaurus 5000D............................................................................................24
Figure 16 - Palm m515...........................................................................................................24
Figure 17 - Sony Clié PEG-T615C..........................................................................................24
Figure 18 - Nokia 7650...........................................................................................................25
Figure 19 - Sony Ericsson T68i...............................................................................................25
Figure 20 - Siemens SL45i.....................................................................................................25
Figure 21 - A spreadsheet and a game implemented for the Siemens SL45i........................25
Figure 22 - Motorola accompli008..........................................................................................26
Figure 23 - Conversion from video picture (left) to IceStream format.....................................29
Figure 24 - WWAN, WLAN and WPAN ranges.......................................................................32
Figure 25 - Mobile network evolution according to Elsen et al. .............................................33
Figure 26 - Mobile network evolution according to De Vriendt et al. .....................................34
Figure 27 - Mobile network evolution according to Myllymäki ...............................................34
Figure 28 - Data rates for 2G, 2,5G and 3G mobile networks ...............................................34
Figure 29 - WAP browsing......................................................................................................37
Figure 30 - i-Mode mobile phone............................................................................................41
Figure 31 - Sony Ericsson P800.............................................................................................63
Figure 32 - Video conferencing on mobile phone...................................................................67
Figure 33 - Surveillance example from Mobile Media's IceStream.........................................68
Figure 34 - Windows Media Player.........................................................................................98
Figure 35 - RealOne Player....................................................................................................99
Figure 36 - PocketTV..............................................................................................................99
Figure 37 - Some screenshots from PocketTV.......................................................................99
Figure 38 - Pocket DivX........................................................................................................100
Figure 39 - Screenshots from Pocket DivX...........................................................................100
Figure 40 - PVPlayer.............................................................................................................101
Figure 41 - Screenshot from PVPlayer.................................................................................101
Figure 42 - IceStream...........................................................................................................101
Figure 43 - The Compaq iPAQ 3850H PDA with D-Link DCF-650W WLAN card................102
Figure 44 - Full screen video on PDA...................................................................................104
Figure 45 - MMS Compuser GUI..........................................................................................105
Figure 46 - MMS Composer GUI..........................................................................................106
Figure 47 - MMS Composer GUI..........................................................................................106
Figure 48 - A sequence of slides and animation...................................................................107
Figure 49 - Exporting MMS message to a mobile phone......................................................108
Figure 50 - Today's service environment..............................................................................116
Figure 51 - Service environment of future 3G network.........................................................117
xv
LIST OF FIGURES
Figure 52 - Screenshots of Monsters Inc. trailer played on RealOne Player........................D-1
Figure 53 - Clip information for two different bit rate versions of the Monsters Inc. trailer....D-1
Figure 54 - Video clip in windowed and full screen mode in RealOne Player.......................D-2
Figure 55 - Pictures from PocketTV, a Star Wars trailer and file information for the trailer..D-2
Figure 56 – Screenshots from PocketTV, video and info about video clip............................D-3
Figure 57 - Windows Media Player playing an MP3 music file and MP3 file info.................D-3
Figure 58 - 56 Kb/s video clip and clip info in Windows Media Player..................................D-4
Figure 59 - 256 Kb/s video clip and clip info in Windows Media Player................................D-4
xvi
PART I - INTRODUCTION
Part I - Introduction
This part contains an introductory chapter, which gives an overview of the issues this thesis
will cover and explains the motivation behind the thesis.
Index
Chapter 1 – Introduction of the thesis .........................................................................3
1.1 Structure of report......................................................................................................3
1.2 Research agenda ......................................................................................................3
1.3 Context for thesis.......................................................................................................3
1.3.1 MOWAHS ............................................................................................................... 3
1.3.2 MOWAHS Background .......................................................................................... 4
1.3.3 Mobility ................................................................................................................... 5
1.3.4 Multimedia .............................................................................................................. 5
1.3.5 Media types ............................................................................................................ 6
1.3.6 Multimedia applications.......................................................................................... 7
1.4 The problem definition ..............................................................................................7
1.5 Motivation....................................................................................................................7
1.6 Goals ...........................................................................................................................7
1.7 Readers Guide ...........................................................................................................7
1
Chapter 1 – Introduction of the thesis
This chapter will give a general presentation and description of this thesis. Firstly the
structure of the thesis is outlined, and then the context around the thesis and the reasons
why this thesis is written is presented. The motivation for investigating this subject is taken
up, and finally there will be a summary of the goals this thesis is trying to accomplish.
This chapter also includes a readers guide with a short explanation of some of the most
important abbreviations and acronyms used in the report.
1.1 Structure of report
This first Part introduces the thesis in general terms, giving the reader a feel of what the
problem domain and technology involved are without going into in-depth specifics.
Part II discusses the technology that dominates this domain, taking into account the history,
the existing and current in-use technology. This thesis concentrates on certain aspects of the
domain, and this will be further explained in Part II.
Part III starts with a discussion of some of the main challenges and restricting factors for
mobile multimedia, and continues with the actual evaluations of technology, which is the
basis for the survey results.
In Part IV, I will try to give an impression of what the future in this area looks like at the
current time. The thesis will be summarized and concluded in Part V.
Part VI contains appendices like references, glossary and technical notes.
1.2 Research agenda
As this thesis is a survey of technologies, the main goal is to give an understanding of the
different technologies, their strong and weak points, and on the basis of this, an evaluation of
these technologies according to some criteria, which will be defined in part IV.
1.3 Context for thesis
This thesis is a part of the MOWAHS [1] project at IDI, NTNU.
1.3.1 MOWAHS
MOWAHS is an acronym that stands for Mobile WOrk Across
Heterogeneous Systems.
MOWAHS is a basic research project at NTNU, supported by the
Norwegian Research Council in its IKT-2010 program. The project is
carried out jointly by the IDI's groups for software engineering (prof.
Reidar Conradi, coordinator) and database technology (prof. Mads
Nygård).
3
Figure 1 - The
MOWAHS “mascot"
The project has two parts:
•
•
Explore process support for mobile users using heterogeneous devices (PC, PDA,
mobile phones)
Explore support for cooperating transactions/workspaces holding work documents.
The project will build upon CAGIS [2] technology and an industrial cooperation is planned.
1.3.2 MOWAHS Background
The Internet is constantly growing, both in the number of users and in the amount of
information available. Nua, an Internet survey company [3], estimates that in August 2001
there were over 500 million users online, and this number will only increase, especially if the
3G mobile technology push where all mobile phones are connected to the Internet is
successful. Sources like IDC [4], another industry surveying company, expect about 3 billion
mobile phones around the world in 2004, with around one tenth of these having access to the
Internet.
The concept of virtual organizations therefore will play a more important role for many people
and companies in the near future. This involves people working distributed across locations
and time zones. Sharing of information will be helped with mobile and both synchronous and
asynchronous technology. At this moment though, there is a lack of tools and infrastructure
for carrying out real projects in virtual organizations efficiently.
In such an environment there will be an extensive heterogeneity in the tools, equipment and
in ways of working.
There is going to be a need to deal with a wide heterogeneity of tools, equipment (laptops,
PDAs, mobile phones) and work models. In addition, mobility of devices and partial lack of
connectivity could require regular synchronization of such devices against stationary servers
and PCs.
A target for the project is to help the research in providing efficient and user-friendly
environments for helping users in virtual organizations and coordinating the work at their
location-mobile, time and device-independent situation.
In support of this research is a big market drive for mobile services, both from user needs
and technology push. The result is a considerable amount of research in this domain. The
research is diversified over a large array of different aspects of the concept of mobile
services.
MOWAHS aims to build on existing local research from the EPOS and CAGIS projects that
have been carried out the last years, using recent middleware technologies like mobile
agents and XML.
The MOWAHS project has stated three goals:
•
•
Helping to understand and to continuously assess and improve workprocesses in
virtual organizations.
Providing a flexible, common work environment to execute and share real
workprocesses and their artifacts, applicable on a variety of electronic devices (from
big servers to small PDAs).
4
•
Disseminating the results to colleagues, students, companies, and the community at
large.
The people involved in the MOWAHS project come from the software engineering and
database research groups at IDI, NTNU. The group consists of teachers, PhD students and
MSc students.
MOWAHS states its approach as a project where:
•
•
•
A flexible work environment for virtual organizations using heterogeneous devices,
with support for processes and their artifacts and transactions is to be defined.
A testbed for process support for virtual organizations, using XML-based and mobile
agents shall be implemented
Real scenarios to evaluate the environment, e.g., for software development and
remote education is to be used.
The desired results from the MOWAHS project covers:
•
•
•
•
•
A formalism to define and execute federated and heterogeneous processes, establish
and control workspaces and cooperating transactions, based on XML.
A simple set of tools to support the above, based on agent technology.
A set of scenarios with defined work models, using the above formalisms.
A body of experiences from empirical studies of such technologies, as articles,
reports etc.
General presentation material and courses/seminars.
1.3.3 Mobility
As Sørensen writes in [5], mobility can distinguished into the terms physical and logical
mobility. Physical mobility then means physical movement of a mobile terminal, and logical
mobility means mobile units of code and state that migrate among hosts. Mobile computing
traditionally means physical mobility, and this is principally the meaning of mobility in this
thesis also, although in some contexts logical mobility may be relevant as well.
1.3.4 Multimedia
This thesis will concentrate on the multimedia possibilities for mobile devices, and as such
will not delve into the specifics of virtual organizations and cooperation across different
systems in the vein of MOWAHS. The point is more to look into what technology the
MOWAHS project will have to deal with when concerned with multimedia issues.
In Webopedia, multimedia is defined as “The use of computers to present text, graphics,
video, animation, and sound in an integrated way.” [6]
The foremost example is perhaps the World Wide Web, which more or less incorporates all
these media types in one application. In this thesis, most of the media involved in the
multimedia term will be graphics, video and sound, but other media types will also be
commented on where appropriate.
5
1.3.5 Media types
The following media types are listed in order of complexity. Note that in the spirit of
multimedia, several of these media types may be combined into a presentation or stream
consisting of several or even all of the following types.
Text
Text is the simplest media type for computers, having the most basic representation of the
different types.
Hypertext (hyperlinking)
The concept of hypertext was introduced with the development of the World Wide Web, and
has in the last ten years become a quite natural media form. In addition to all the properties
of regular text, hypertext has linking capabilities, which makes it a special database system.
The links can also reside in pictures.
Hypertext is stored as text files containing tags that are the linking elements, and also can be
formatting elements for the text. Hypertext makes the reading of text more interactive, as the
user can select topics in the text that he/she wants to explore further.
Graphics (pictures)
Still images have long been the cornerstone in the multimedia concept, as computers were
not always able to display moving pictures as easily as they have been the last years. Still
images are still a very important part of multimedia, as we can easily see on the World Wide
Web.
Sound
In multimedia, visual and aural impressions make out the two main components. The visual
components can have many different manifestations, but the sound component does not
have many different forms other than different qualities. The quality manifests itself in clarity
and number of different channels. Sound media contains a temporal component, in that it
cannot be recognized at a given instant in time, the meaning of audio information is spread
over time.
Animation
Animation is generally seen as being moving images, but on computer displays they are not
recorded in the same way, but is animated using graphic languages, making the computer
draw out the moving imagery on the screen. An example of animation is Flash graphics
animations.
Video
The concept of video in terms of multimedia refers to moving images on a display, and being
of a recorded nature. This is just displayed on the screen as it was recorded with a camera.
The difference between video and animation can be stated as being the same as the
difference between a photo and a drawing. Of course, animation can be transferred and
stored digitally as video data, in a similar fashion that a drawing can be photographed.
6
1.3.6 Multimedia applications
Some examples of current applications of multimedia are e-learning tools on CD-ROM and
the World Wide Web. An up and coming multimedia concept is the Multimedia Messaging
Service (MMS), which is presented in section 5.4. It is generally believed in the
telecommunications industry that multimedia services like MMS will become popular on
portable devices in the near future.
1.4 The problem definition
The following quote is the actual text of the thesis problem:
“The task is to try out different client technologies on mobile equipment, in order to discover
challenges and restrictions with these kinds of technology. Especially the transmission and
presentation aspect of multimedia to and from mobile equipment are in focus. Examples of
this are digital video transmission using mobile phones or streaming of video and sound to
PDAs.”
In order to complete this task, a study of the existing technology has to be made. This is
presented in part II. Furthermore, part III goes specifically into the difficulties that exist in the
field and makes some proposals for solutions to these problems.
An evaluation of technologies is then made, both existing technologies and up and coming
technologies that are to be introduced in the near future.
A large part of the thesis is the study and presentation of relevant technologies. Part II, which
contains this work therefore makes out a considerable share of the total work that has been
put into this report. Even though this should be regarded as a part of the results of this thesis,
it has been placed in the prestudy section of the report, as it makes the basis for the
evaluations that are made later.
1.5 Motivation
The technologic development is very rapid, especially in this area where there is a lot of
consumer interest not only for corporations, but also for private users. The motivation for this
thesis is a need for information about what technology is available, and what will be available
in the future. In addition it tries to evaluate the relevant technologies and to give an outline of
the development in this segment of the computing industry.
1.6 Goals
The intention with this thesis is to collect information and make a qualified evaluation of the
technologies concerning multimedia issues for wireless. This information can be utilised by
the MOWAHS project if and when needed.
1.7 Readers Guide
To be able to get the most out of this thesis, the reader should be familiar with concepts like
networks, multimedia and mobility. Although this thesis explains many of the concepts
involved in mobile multimedia, some prior understanding of the subject is beneficial.
7
This thesis contains two distinct portions. The first is the prestudy in Part II, which contains
information about available and some of the technology in development. This is the basis for
the evaluation that is made later. The evaluation as such, together with opinions on the
current state and future of this domain, are presented in the second portion, consisting of
parts III and IV.
The prestudy could be interesting enough in itself, if the reader would like to get an overview
of the discussed technologies but is not interested in a direct comparison and evaluation. If
the reader is familiar with these technologies already, and would just like to read the
evaluation parts, the second portion would be sufficient.
In appendix B there is a comprehensive glossary that explain all acronyms used in this
thesis, but to ease the reading of this report, the most important and widely used are
explained in short here in Table 1.
EDGE
GSM
GPRS
HSCSD
PDA
UMTS
Enhanced Data Rates for GSM Evolution. An enhancement of the
current GSM technology, enabling greater data transfer rates.
Global System for Mobile Communications. GSM is a popular digital
wireless communications technology.
General Packet Radio Services. Packet Switched data radio
technology for GSM networks.
High Speed Circuit Switched Data. An enhancement to GSM
networks that enables data speeds to be boosted.
Personal Digital Assistant. A small, portable device used for
computing.
Universal Mobile Telecommunication System. A third generation
mobile communication system currently in development.
Table 1 - Important acronyms
8
PART II - PRESTUDY
Part II - Prestudy
This part describes the subjects that were necessary to have as the basis for the survey of
multimedia technology. It contains mostly technology information, but ends with information
about usage of multimedia.
It will firstly give a presentation of the current technology, both in the hardware, software and
network domains. It will then introduce different media types, and discuss certain aspects of
media transfer. A presentation of mobile media related scenarios will be given, and finally,
state-of-the-art and related work is presented.
Index
Chapter 2 – Client technology......................................................................................13
2.1 Portable/mobile devices..........................................................................................13
2.1.1 Laptop computers................................................................................................. 13
2.1.2 Personal Digital Assistants................................................................................... 14
2.1.3 Mobile phones ...................................................................................................... 15
2.1.4 Other types of portable units ................................................................................ 16
2.2 Alternative classification .........................................................................................16
2.2.1 Operating systems for portable devices .............................................................. 17
2.2.2 EPOC (Symbian).................................................................................................. 18
2.2.3 PalmOS (Palm).................................................................................................... 18
2.2.4 Pocket PC (Microsoft) .......................................................................................... 19
2.3 Development and application environment for portable devices .....................21
2.3.1 J2ME ..................................................................................................................... 21
2.3.2 CLDC.................................................................................................................... 21
2.3.3 MIDP..................................................................................................................... 21
2.4 Examples of portable devices ................................................................................22
2.4.1 Laptop: Dell Inspiron 2650 ................................................................................... 22
2.4.2 Pocket PC PDA: Compaq iPAQ 3850H Pocket PC ............................................ 23
2.4.3 Pocket PC PDA: Casio E-200 CASSIOPEIA Pocket PC 2002 ........................... 23
2.4.4 Linux PDA: Sharp Zaurus 5000D......................................................................... 24
2.4.5 Palm PDA: Palm m515 ........................................................................................ 24
2.4.6 Palm PDA: Sony Cliè PEG-T615C ...................................................................... 24
2.4.7 Mobile phone: Nokia 7650 ................................................................................... 25
2.4.8 Mobile phone: Sony Ericsson T68i ...................................................................... 25
2.4.9 Mobile phone: Siemens SL45i ............................................................................. 25
2.4.10 Mobile phone: Motorola accompli008 ................................................................ 26
Chapter 3 – Media player applications.......................................................................27
3.1 Media Players ...........................................................................................................27
3.2 Windows Media Player ...........................................................................................27
3.3 RealOne Player........................................................................................................28
3.4 QuickTime .................................................................................................................28
3.5 PacketVideo PVPlayer ............................................................................................28
3.6 IceStream ..................................................................................................................29
3.7 Pocket DivX ..............................................................................................................30
3.8 PocketTV ...................................................................................................................30
9
PART II - PRESTUDY
3.9 PhotoSuite .................................................................................................................30
3.10 Other Media player applications ..........................................................................31
Chapter 4 – Network technologies..............................................................................32
4.1 WWAN, WLAN, WPAN ...........................................................................................32
4.2 Mobile networks (WWAN) ......................................................................................33
4.3 Second generation mobile networks.....................................................................35
4.3.1 Global System for Mobile Communications (GSM) ............................................. 35
4.3.2 TDMA.................................................................................................................... 36
4.3.3 CDMA ................................................................................................................... 36
4.3.4 PDC ...................................................................................................................... 36
4.3.5 Short Message Service (SMS)............................................................................. 37
4.3.6 WAP...................................................................................................................... 37
4.3.7 High Speed Circuit Switched Data (HSCSD) ...................................................... 38
4.4 2,5G - Evolved second generation mobile networks..........................................38
4.4.1 General Packet Radio Service (GPRS)............................................................... 38
4.4.2 MMS (Multimedia Messaging Service) ................................................................ 41
4.4.3 i-Mode................................................................................................................... 41
4.5 3G – Third generation mobile networks ...............................................................41
4.5.1 EDGE.................................................................................................................... 43
4.5.2 UMTS.................................................................................................................... 43
4.5.3 cdma2000............................................................................................................. 44
4.6 Wireless network technologies (WLAN & WPAN) ..............................................45
4.6.1 The 802.11 series................................................................................................. 45
4.6.2 The HiperLAN technologies ................................................................................. 47
4.6.3 Bluetooth .............................................................................................................. 47
4.6.4 The WLAN standard muddle................................................................................ 48
4.6.5 Interworking WLANs and WWANs ...................................................................... 48
4.7 Network summary....................................................................................................50
Chapter 5 – Media architectures ..................................................................................51
5.1 Codecs and file formats ..........................................................................................51
5.2 Media Formats..........................................................................................................51
5.2.1 MPEG formats ...................................................................................................... 51
5.2.2 RealPlayer ............................................................................................................ 53
5.2.3 QuickTime ............................................................................................................ 53
5.2.4 Microsoft’s Window media files ............................................................................ 54
5.2.5 DivX...................................................................................................................... 55
5.2.6 Other media formats............................................................................................. 55
5.3 Media content and interface languages ...............................................................56
5.3.1 SGML .................................................................................................................... 56
5.3.2 HTML .................................................................................................................... 56
5.3.3 XML ...................................................................................................................... 56
5.3.4 WML ..................................................................................................................... 56
5.3.5 SMIL ..................................................................................................................... 56
5.4 Multimedia Messaging Service (MMS).................................................................57
Chapter 6 – Streaming ....................................................................................................58
6.1 Streaming ..................................................................................................................58
6.2 Pseudo-streaming ....................................................................................................59
6.3 Streaming media players ........................................................................................59
6.4 Streaming infrastructure .........................................................................................60
6.5 Streaming software..................................................................................................60
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PART II - PRESTUDY
6.6 Buffering ....................................................................................................................60
6.7 Compression.............................................................................................................60
6.8 Quality of Service.....................................................................................................61
6.9 Multiple Bit Rate Encoding .....................................................................................62
Chapter 7 – Market issues .............................................................................................63
7.1 Hardware demands .................................................................................................63
7.2 Network demands ....................................................................................................64
7.3 Market demands ......................................................................................................64
7.4 Video Services Today and Tomorrow ..................................................................65
Chapter 8 – Multimedia scenarios...............................................................................67
8.1 Scenario classes ......................................................................................................67
8.1.1 Video Conferences............................................................................................... 67
8.1.2 Instruction ............................................................................................................. 68
8.1.3 Surveillance.......................................................................................................... 68
8.1.4 Entertainment ....................................................................................................... 69
8.1.5 Advertising ............................................................................................................ 69
8.1.6 Information Services............................................................................................. 69
8.1.7 Location Oriented services................................................................................... 70
8.1.8 Data Transfer........................................................................................................ 70
8.2 Scenario summary...................................................................................................70
Chapter 9 – The state-of-the-art in today’s situation .............................................71
Chapter 10 – Related work ............................................................................................72
10.1 Comparison to this thesis .....................................................................................73
11
PART II - PRESTUDY
Chapter 2 – Client technology
This chapter concerns the actual client devices involved in a mobile multimedia scenario. In
that lays both a hardware aspect and also a software aspect through the operating systems
for the devices.
2.1 Portable/mobile devices
In this section the concept of portable or mobile devices will be clarified for the context of this
thesis and a classification and further description of portable devices will be made.
Portable devices are practical in many situations. In some of these situations portability is
essential, whilst in others it may only be a convenience.
The degree of portability depends on the unit’s size and
weight as well as the way the device is connected to a
network, if applicable. In a MOWAHS paper [7], the
authors compares different sized mobile units with
respects to that paper’s subject, which is an evaluation of
a mobile task reporting system for mobile devices.
Other expressions that are used about portable devices
are “mobile” and the term “nomadic” which was more
used before mobile phones became widely used.
Portable devices range from the quite large laptop
computers, through handheld computers, like PDAs, to
even smaller devices, like mobile phones. Even smaller
gadgets like pagers can also be put into the portable
device category, but as the multimedia options on these
kinds of equipment are extremely limited, they will not be
covered in this thesis.
Figure 2 – Laptop computer
from Dell
2.1.1 Laptop computers
Laptop computers are typically very powerful computers,
Figure 3 - Sony VAIO C1
in most respects comparable to desktop computers.
Picturebook
They feature full operating systems and have very good
processing power and multimedia features. Figure 2 shows an example of a typical laptop
computer.
Network connection is often achieved by regular TCP/IP
Internet connection, either through ordinary LAN
connection or by some sort of wireless LAN. More mobile
solutions for laptop computers would be using a mobile
phone as Internet connection, although this severely
affects the network capacity with today’s mobile phone
networks.
In the segment between laptop computers and PDA’s,
are a group of computers that perhaps can be called
handheld computers or small notebook computers.
13
Figure 4 - HP Jornada 720
PART II - PRESTUDY
These are sized between laptops and PDA’s, and features in most cases a keyboard and a
reasonably sized screen. One example of a more powerful version of this is the Sony VAIO
C1 Picturebook which can run standard operating systems like laptop computers do, another
more modest example is the HP Jornada 720 Handheld PC which runs the Microsoft
Handheld PC operating system, a version of WinCE. Figure 3 shows the Sony VAIO
Picturebook, and Figure 4 shows the HP Jornada 720.
2.1.2 Personal Digital Assistants
A category of computers that have had a big increase in
attention and development in the last years are Personal
Digital Assistants, or PDAs as they will be called here. They
are usually seen as keyboardless units with a touch sensitive
screen interface.
The first real PDA was introduced by Apple in 1993, and was
called Newton, shown in figure 5. A few years passed before
the world really got their eyes open to this concept. Palm
launched its PalmPilot series in 1996, and this was probably
when PDAs had their breakthrough in the mass market. One
of the first Palm PDAs, the Palm pilot 5000 is shown in figure
6.
Figure 5 - Apple
Newton
More companies have later joined the PDA craze, and this
competition makes rapid development of more powerful PDAs
possible and necessary. Companies involved with PDA
manufacturing today are among others Palm, Psion/Symbian,
Compaq, Sony, Motorola, HP, Apple, IBM, Toshiba,
Handspring and Sharp. The newest Handspring model, the
Handspring Visor Prism is shown in figure 7.
As for operating systems on PDAs, there are two solutions that
lead the market, Pocket PC (or Windows CE) by Microsoft,
and PalmOS which has been developed by Palm.
The Pocket PC OS is used by many of the companies making
PDAs, Microsoft themselves does not manufacture PDA
hardware. PalmOS is of course used in the Palm PDAs, and
some other companies also make use of this OS in their
products. Sony, Handspring, Symbol, HandEra and IBM are
among these.
Figure 6 - Palm pilot
5000
A simple description of PDAs is as small handheld personal
computers with limited processing and storage capabilities.
This description is typical of the current situation, but is not
definitive. Future models will most probably try to catch up with
regular PC power and functionality, and although PDAs
probably will not catch up to standard PCs completely, they
will not be lagging very far behind.
A few years ago PDAs were not much more than expensive
and complex addressbooks, also called “Personal Organisers”,
but today some of the models are even sufficiently equipped to
play and display audio and video clips.
14
Figure 7 - Handspring
Visor Prism
PART II - PRESTUDY
Network connectivity has until recently been achieved by so-called docking, in which the user
connects the PDA to a PC, where information gets transferred to the PDA. The newest
technology makes this docking procedure obsolete for mobile purposes though, with WLAN
and mobile phone cards being made available for most PDAs. In this way the PDA user can
be online and mobile at the same time.
2.1.3 Mobile phones
Mobile phones are probably the most exciting category of portable equipment development
for several reasons. The fact that the user base for this equipment involves a very wide
demographic group, in addition to the ever decreasing size of complex components mean
that there is an increasing possibility of putting more and more functionality into a small unit.
In the beginning of mobile phone history, the mobile phone was
nothing more than a circuit-switched analogue phone unit that
happened to be mobile. The first multinational mobile phone system
was NMT450, which was introduced in Denmark, Finland, Norway
and Sweden in 1981. Apart from this there were many different and
incompatible analogue systems with each system belonging to one
country and using a certain frequency band. This made it nearly
impossible to move between different systems. Figure 8 shows one
of the early mobile phone models.
A common European digital system for mobile phones was the
solution. It was called GSM, and this was the beginning of secondgeneration mobile networks, which has evolved even further and
now is the basis for the future mobile networks.
Figure 8 - An old
Nokia mobile
phone
In a press release on May 11, 2001, Ericsson stated that the
number of GSM users had reached 500 million [8].
The mobile phone units themselves have been getting smaller and
smaller, but for being useful as a handheld telephonic unit there is a
limit for how small a mobile phone should be. Even so, new
technology will surely be able to put mobile phone connectivity into
even smaller products, but that will probably be as mobile
connection peripherals for computers or PDA’s.
Today’s popular mobile phones all have a screen and a numeric
keyboard with some navigational keys in addition to the obligatory
speaker and microphone for audio. The specifications of the display
vary a bit, but a display resolution of around 90 x 60 pixels is
common. This will probably change though, as new services from
the new generations of mobile networks enable more use of
displayable content to be sent to the phones. The monochrome,
small-resolution screens that are common today do not really
encourage multimedia use. Therefore the new models that mobile
phone vendors are introducing these days have better displays, with
better resolution and colour displays. Figures 9 and 10 show some
typical mobile phones of today.
Figure 9 - Nokia
3210
Figure 10 Siemens SL45i
Most mobile phones available today does not have a “standardized” operating system, but as
the mobile phones are rapidly moving in the direction of becoming small PDA-like units, we
see that some of the more advanced mobile phones are adopting the use of what we can call
15
PART II - PRESTUDY
standard OS’s, like PalmOS from Palm, Windows CE from Microsoft and EPOC 32 from
Symbian.
2.1.4 Other types of portable units
Of course there are units that fall in between of these categories, or rather they can belong to
more than one category. There are PDAs that come with small keyboards on the unit or more
regularly sized external keyboards, and lately quite a few combined PDA/mobile phone
solutions have been presented by different vendors like Nokia, Sony Ericsson and
Handspring. These have been dubbed Smartphones or Communicators, and are still quite
expensive and bulky. However, since components continually become more integrated and
miniaturized, these products will surely become more portable, stylish and reasonably priced
with time. Figure 11 shows a selection of such devices.
Figure 11 - Psion Revo, Ericsson R380, Nokia 9210 and Handspring Visor Phone
2.2 Alternative classification
As well as with differences in the hardware of these laptop/PDA/mobile phone classes they
can also be differentiated into categories of operating systems. The operating system should
not influence the ability of playing multimedia data too much, as this is a softwareprogramming problem that surely can be overcome for most operating systems.
Nevertheless the most available and relevant operating systems will be presented here. First,
operating systems for laptop computers are presented in short as these are rather well
known. Then, the most important operating systems for smaller portable devices are
presented in more depth.
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PART II - PRESTUDY
Microsoft Windows (95,98,Me,NT,2000,XP)
Microsoft Windows in all its incarnations is the most widespread
operating system for full-fledged computers. This is a family of
operating systems for personal computers. Windows dominates the
personal computer world, running, by some estimates, on 90% of all
personal computers. Microsoft Windows is considered as a very good operating system for
multimedia use, as it is very versatile and has a huge amount of available multimedia
applications, in addition to that it is a quite easy to use system for non-professionals.
Windows Media Player is the standard media playing application that is shipped with these
operating systems, but a wide range of other software are available free of cost.
Unix
There is a multitude of different Unix operating systems, each with their
own characteristics. The most well known family is Linux, in which there
also are a number of different distributions. UNIX has historically been
most popular in academic uses, and is considered to be a system
aimed more at expert users. The multimedia capabilities are good, but not as accessible as
on the Windows platforms. Freeware applications like xshow and xine are examples of media
viewing applications for Unix.
MacOS
MacOS is only readily available for Apple Macintosh computers. This is
perhaps most known for being a user-friendly operating system, as well
as “the alternative to Microsoft Windows”. Multimedia options are more
limited than for Windows though, as Apple has a tendency to constrain
the standard releases of their operating systems to their own standards.
An example of a media player/format is QuickTime, which has its origin at Apple and which
will be presented thoroughly in chapter 5.2.4. Of course, third party software is also available
to expand the multimedia capabilities.
2.2.1 Operating systems for portable devices
There are three main contenders in the marketplace for mobile operating systems, namely
Palm with PalmOS, Symbian with EPOC and Microsoft with Windows CE/Pocket PC. There
are also some proprietary operating systems, which are not expected to make significant
impact on the market. In addition there are several stale operating systems that are no longer
being produced or updated. These will not be presented here.
The only alternative contender to the three market leaders may be a mobile version of the
open source Linux operating system, and although there are not many available products at
present, there are significant moves in this area. The Sharp Zaurus is a relatively new PDA
where the operating system is based on Linux and Java. With the advantages that open
source software provides, namely a worldwide, free development community, it is important
to keep track of developments in this area.
17
PART II - PRESTUDY
Each of the three named operating systems is backed by a number of hardware equipment
manufacturers. Table 2 groups the manufacturers according to what operating system they
are supporting. Note that some companies are backing more than one OS, in this overview
Sony and Symbol.
Symbian EPOC
Palm PalmOS
Microsoft Pocket PC
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Sony Ericsson
Motorola
Nokia
Psion
Matsushita
Philips
Sony
Sanyo
Palm
IBM
Sony
Dell
Handspring
Symbol
Qualcomm
TRG
Compaq
HP
Casio
Symbol
Siemens/Fujitsu
Toshiba
Table 2 - Hardware equipment backing for the three most important mobile operating systems
2.2.2 EPOC (Symbian)
Symbian was set up in 1998 by Psion, Motorola, Nokia and Ericsson
and was joined by Matsushita a year later. With a very significant
share of the mobile phone market worldwide (about 60%), Symbian
has a commanding position in this area [9]. The company is also enjoying some momentum
along with companies like Sony and Sanyo, who joined in August 2000.
EPOC is used in a limited number of products on the market available today, including Psion
hand-held PCs, Sony Ericsson’s R380 and recently Nokia’s 9210i Communicator. With the
newest versions of the EPOC operating system incorporating voice, there will be a number of
new products launched from the mobile phone manufacturers. EPOC is being developed in
three different versions: one for Smartphones, the voicecentric devices with data
functionality, one for Communicator-like devices in the Nokia Communicator form factor, and
a third in the tabletstylus form factor like traditional PDAs.
EPOC already includes much of the basic functionality such as PIM (personal information
manager), integrated e-mail, Web browser and synchronisation capabilities. Future versions
will include improved versions of the WAP browser, Bluetooth support, increased security
and improved e-mail and messaging capabilities. Symbian enjoys support from a number of
major partners including NTT DoCoMo, Sun, Oracle and Sybase. It claims to have a
following of over 31,000 software developers worldwide [10].
2.2.3 PalmOS (Palm)
Palm has by far the largest share of market shipments and installed
base. The first Palm products were sold in 1996. Since then it has
openly licensed the operating system and attracted a number of
hardware manufacturers. IBM and Dell also resell original PalmPilot
devices. However, Handspring, a company set up by the original
developers of the PalmPilot, is rapidly increasing its shipments and could become the largest
PalmOS hardware provider as it is offering low cost, expandable devices.
As the most mature platform of the three, it enjoys the largest number of applications and
application developers. The platform includes a lot of the basic PDA functionality such as
18
PART II - PRESTUDY
PIM, e-mail and messaging. One of Palm’s advantages is that the hardware manufacturers
have enabled expandability of the devices through a number of different formats including
CompactFlash, Springboard and Palm clip-on. Future product development is focusing on
wireless connectivity, Bluetooth support and improved language support. PalmOS enjoys
support from the most important software developers including Computer Associates,
IBM, Oracle, Peoplesoft, SAP, AOL, Sun, Siebel and Tivoli. Palm claims to have over 50,000
software developers working on its platform [10].
Functionally, PalmOS seems to be lagging behind Pocket PC in its current version, PalmOS
4. However, there are signs that a new version is on the way in the second half of 2002.
Palm OS 5 will include better screen resolution (320x320), better multimedia options, IEEE
802.11b connectivity and more powerful processors, namely ARM, in the same family as
processors used in Pocket PC devices [11].
2.2.4 Pocket PC (Microsoft)
The first Windows-powered hand-held PCs became available in 1997.
Microsoft’s success has been limited with its Windows CE products and
earlier versions of the operating system were limited in performance and
functionality, with resulting disappointing sales.
A number of hardware manufacturers, such as Philips and Uniden, had to pull out of the
market. However, with the introduction of the Pocket PC brand, which refers to the Windows
CE operating system on mobile devices, Microsoft seems to have got a better scheme on
their hands. With better fundamental aspects such as colour, expandability and user
interface, better connectivity support, well-designed hardware and a variety of software
developers, Pocket PC is expected to take a fair chunk of the marketplace. This can be seen
from the lack of supply of Compaq’s much sought after iPAQ products recently.
Building on the standard Pocket PC 2002 software, the Pocket PC 2002 Phone Edition also
adds support for data and voice communications to enable integrated wireless Pocket PCs.
This offers already existing wireless scenarios such as email, web browsing, and Instant
Messaging, while new features offer mobile phone functionality, including voice
communication and SMS text messaging.
Table 2 compares the three presented operating systems further [12].
19
PART II - PRESTUDY
Operating System Summary
Operating system
Advantages
Disadvantages
Other Comments
•
Microsoft launching
huge speech and
wireless initiative (server
infrastructure)
•
System crashes
•
•
No integrated wireless
connectivity yet
Better audio support
(mp3s), wider range of
multimedia applications
•
Better multimedia
PDAs– richer
applications, broader
sound, and video
support.
Performance lag when
multi-tasking
•
Built-in character
recognizer problematic
•
Lack of supply (i.e.,
iPAQ)
•
Pocket PC
•
PalmOS
EPOC
Continuous PC
synchronisation
•
Stable system (very few
crashes).
•
Limited audio support,
low image quality
•
Current leader in the
PDA race
•
Head start with wireless
connectivity; wireless
Web access for all
models is targeted
•
16-bit, lack 32-bit power
•
•
Less memory than most
Pocket PC devices
Best PDA for power
users focused on
maximizing basic
personal information
manager (PIM),
functionality and mobility
(tend to weigh less)
•
OS more dominant for
smartphones, but there
are two versions of the
OS for palm-sized
devices (Quartz and
Crystal)
•
Many companies
utilizing Symbian
technology in their
equipment, including
Ericsson, Matsushita
Electric, Motorola,
Nokia, Philips
Electronics, Sony and
most recently, Sanyo
•
Better battery life
•
Easy interface
•
Longer battery life due
to less power
consumption
•
Memory efficient
applications
•
More easily integrated
with local networking
standards such as
Bluetooth & IrDA
•
Currently, few
handhelds based on this
OS (Psion Revo is
major)
•
Focus on telecom
integration, technologies
such as WAP
•
Many products still in
development stage
(especially co-branded
products)
•
Very stable, very few
crashes
•
Requires little memory
•
Runs much faster on
comparable speed chip
than competitors
•
32-bit interface
•
More extensible &
flexible
Table 3 - Overview of mobile operating systems
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PART II - PRESTUDY
2.3 Development and application environment for portable devices
Again laptop computers are a special case since they use the same operating systems as
regular PCs, such as C/C++, Delphi and Java. Those kinds of development environments will
not be presented here.
Instead it is the development environments for the smaller portable devices that are the topic.
These environments makes it possible to program new applications for the small devices.
This is quite a step for mobile phones for example, which previously only had the more or
less simple applications that were stored on the phone when purchased. With such
development possibilities new applications can be made that are aimed at specific user
groups, instead of generic applications that can be neither upgraded nor removed, for
instance the obligatory calculator “application”.
2.3.1 J2ME
J2ME is short for Java 2 Platform Micro Edition. J2ME is Sun Microsystems' answer to a
consumer wireless device platform. J2ME allows developers to use the Java programming
language and related tools to develop programs for mobile wireless information devices such
as cellular phones and personal digital assistants (PDAs). J2ME consists of programming
specifications and a special virtual machine, the K Virtual Machine, that allows a J2MEencoded program to run in the mobile device. J2ME consists of two elements, configurations
and profiles [13], [14], [15].
Configurations provide a set of libraries and a virtual machine for a category of wireless
device. There are two configurations for J2ME, one for fixed wireless devices and one for
mobile wireless devices.
Profiles are APIs built on top of configurations to provide a runtime environment for a specific
device, such as a PDA, cellphone, or set-top box. The profile manages the application, user
interface, networking and I/O.
In order to support Java applications, manufacturers need to implement a profile for their
specific devices. Devices with systems that exploit J2ME are already available and are
expected to become even more available in the next few years.
2.3.2 CLDC
There are two programming specifications, the first is Connected, Limited Device
Configuration (CLDC). CLDC lays out the application program interface (API) and virtual
machine features needed to support mobile devices.
2.3.3 MIDP
The second programming specification for J2ME is MIDP. MIDP is short for Mobile
Information Device Profile. MIDP adds to the CLDC the user interface, networking, and
messaging details needed to interface with mobile devices. MIDP is therefore a set of J2ME
APIs that define how software applications interface with cellular phones and two-way
pagers.
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PART II - PRESTUDY
Applications conforming to this standard are called MIDlets. MIDlets are small Java
applications similar to an applet but one that conforms with CLDC and MIDP and is intended
for mobile devices.
Companies that have worked on the MIDP include AOL, Bull, Ericsson, Fujitsu, Matsushita
(Panasonic), Mitsubishi, Motorola, Nokia, NTT DoCoMo, Oracle, Palm Computing, Research
In Motion (RIM), Samsung, Sharp, Siemens, Sony, Sun Microsystems (Specification Lead),
and Symbian.
2.4 Examples of portable devices
Comparisons between mobile devices can be done in two different ways, either as a
comparison between all portable devices, or as a comparison between members within a
class of portable devices. In this thesis, there will in this chapter first be examples of a few
typical portable units where the reader can compare the specs of these units, and in chapter
13 there will be a more critical evaluation of devices where the comparison will be between
the different classes of units. The following few sections present some examples of typical
units for the particular device classes. For more information about the units visit the
respective web pages for that company.
2.4.1 Laptop: Dell Inspiron 2650
This laptop features a Mobile Intel Pentium 4 processor working at 1.4GHz, 1.5Ghz, 1.6GHz
or 1.7Ghz. It comes with 128 MB of memory as standard, upgradeable to 512 MB maximum.
It comes in two sizes according to the screen size, either 14.1 or 15 inches.
With 14.1-inch display it has the following measurements:
Width: 328 mm, depth: 275 mm, height: 36 mm.
It weighs 3.22 kg with CD, floppy and battery.
With 15-inch display it has the following measurements:
Width: 332 mm, depth: 275 mm, height: 38 mm.
It weighs 3.56 kg with CD, floppy and battery.
Figure 12 - Dell Inspiron
Approximate operating time is 2-3 hours, but this of course
2650
depends on usage. The unit has the sound capabilities of a
regular PC, with its built in speakers and soundcard. The
display is capable of multiple resolutions, with 1024 x 768 pixels as maximum. With a
powerful graphics card it is very capable in the graphics department.
Storage properties are dependant on the users wishes, but Hard Drives of 20, 30 or 40 GB is
common. As for removable storage, the Dell Inspiron can use CD-ROM, DVD-ROM, CDRW,
CDRW/DVD and floppy drives.
Networking can be achieved using the built-in modem port, an optional integrated Ethernet
port, or through the use of one of many available general networking options using
expansion cards and other equipment.
With a standard Intel processor this unit can operate using one or more of a multitude of
operating systems like Microsoft Windows, different UNIX versions and others.
The price for this unit is around $2000.
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PART II - PRESTUDY
2.4.2 Pocket PC PDA: Compaq iPAQ 3850H Pocket PC
This is an example of the popular Compaq iPAQ PDA series, and is one of the newest and
most powerful Pocket PC units. Combined with an expansion card jacket, this PDA can be
connected to WLAN and mobile phone networks (GPRS/GSM). The newest model (3870)
also includes embedded Bluetooth capabilities.
This unit features a 3,5” color-reflective TFT liquid crystal
display with 65,536 available colours. It also has the
usual Pocket PC screen resolution of 240 x 320 pixels
with a pixel pitch of 0.24 mm, and the viewable image is
57 mm wide x 77 mm tall
Processing wise it has a 206 MHz Intel® Strong ARM
1110 32-bit RISC Processor, which is common for
Pocket PC’s these days. It has 64 MB RAM for storage
of files and applications, in addition to 32 MB Flash
ROM.
The audio in/out options consist of microphone, speaker
and an audio out jack.
Figure 13 - Compaq iPAQ
3850H
The weight of the unit is 190 grams, and it has
measurements of 130 x 84 x 16 mm. The expansion card
jacket including expansion card about the doubles its weight, and makes it quite a bit larger.
The battery life is about 10 hours, depending on usage and screen lighting setup.
The price for this unit is around $599, with additional cost for network expansion units around
$200.
2.4.3 Pocket PC PDA: Casio E-200 CASSIOPEIA Pocket PC 2002
The Casio E-200 CASSIOPEIA is Casio’s most recent
Pocket PC PDA. This unit is very similar to the Compaq
described earlier, which does not come as a surprise,
since all the newest Pocket PC units both look and work in
very similar ways.
It has a similar 65,536 colour display with 240 x 320 pixel
resolution, but the screen is a little smaller. It uses the
same Intel Strong ARM 1110 206MHz processor also, and
has the same memory set-up as the Compaq model.
This unit can also be expanded using an external unit,
making IEEE 802.11b and Bluetooth networks available.
Casio claims that this PDA has 12 hours of battery time,
and it’s measurements are stated to be 130 x 81 x 18 mm,
weighing 190 grams.
The Casio E-200 CASSIOPEIA costs $599.
23
Figure 14 - Casio E-200
Cassiopeia
PART II - PRESTUDY
2.4.4 Linux PDA: Sharp Zaurus 5000D
The Sharp Zaurus 5000D, is a new, high-end PDA that ships
with Linux and PersonalJava technology preinstalled. This
indicates that the Linux OS is coming to the PDA market as
well.
The Sharp Zaurus SL-5000D Linux/Java PDA runs on the
206MHz Intel SA-1110 StrongARM system-on-chip
processor and has 32MB SDRAM memory. The display is a
3.5-inch 240 x 320 pixel reflective TFT 65,536 colour LCD
with touch panel support.
A feature that is a bit special with this unit is the keyboard, a
front lighted QWERTY keyboard with a slide cover.
Figure 15 - Sharp Zaurus
5000D
The unit measures 137 x 74 x 18 mm and weighs 188 grams. The Sharp Zaurus 5000D
costs $499.
2.4.5 Palm PDA: Palm m515
The Palm m515 is the most advanced device available from the
Palm Company. It features a 33 MHz Motorola Dragonball 32 bit
CISC processor and has 16 MB RAM as standard.
The 2,5 inch screen has a 160 x 160 pixel resolution and can
display 65536 colours. Palm PDAs also feature a “graffiti area”,
which is used for writing. This makes the screen area smaller
than it appears, as the graffiti area looks like a part of the
display, but is not.
The Palm m515 offers embedded Bluetooth connection
capabilities, using a Bluetooth card.
Figure 16 - Palm m515
The size of a Palm m515 is 114 x 79 x 10 mm, it weighs 113 grams and costs $399.
2.4.6 Palm PDA: Sony Cliè PEG-T615C
This PDA using the PalmOS operating system is a special
version of the Palm PDA, as it features double resolution,
320x320 pixels, on the display. This is what the screen
resolution on future Palm models using PalmOS 5 [10, ref
palm OS] is going to be like. On Sony models, this is a nonstandard implementation and applications will have to be
optimized to use this feature.
Other than that it is a reasonably standard Palm PDA, with the
33 MHz Motorola Dragonball processor, and 16 MB RAM
memory.
The Sony Clié PEG-T615C is 12.5 mm thick, and costs $299.
24
Figure 17 - Sony Clié
PEG-T615C
PART II - PRESTUDY
2.4.7 Mobile phone: Nokia 7650
The newest Nokia mobile phone model is not publicly
available at the moment, but its specifications have
been made public. Its main new functions include a
colour display, built-in digital camera, MMS capabilities
and GPRS network.
It will have a graphic display capable of 176 x 208
pixels with 4096 colours, and with the display
measuring 35 x 41 mm.
It is not the smallest Nokia phone measuring 114 x 56
x 26 mm, and weighing 154 grams.
Figure 18 - Nokia 7650
Perhaps the most exiting feature of this model is the possibility of sending one’s own
composed MMS messages composed of pictures taken with the camera and sound recorded
by the microphone.
2.4.8 Mobile phone: Sony Ericsson T68i
This is the most recent Sony Ericsson mobile phone, featuring
a colour display, MMS capabilities and GPRS connectivity.
This mobile phone also has Bluetooth, which means that it can
be connected to another portable unit like a laptop or PDA to
make a GPRS network connection for these kinds of unit.
It weighs 84 grams, and measures 100 x 48 x 20 mm.
The display is 34 x 28 mm, and can display 101 x 80 pixels
with a colour depth of 256 colours. The Sony Ericsson T68i
costs about $599.
Figure 19 - Sony
Ericsson T68i
2.4.9 Mobile phone: Siemens SL45i
This is a Java-enabled mobile phone featuring MIDP (covered in
section 2.3.3), which makes it possible to develop new
applications for it. Some examples are shown in figure 21.
Figure 20 - Siemens
SL45i
Figure 21 - A spreadsheet and a game
implemented for the Siemens SL45i
It has a monochrome display with 101x 80 pixels and also has a built in MP3 player, which
really is separated from the telephone part of the unit. It costs around $300.
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2.4.10 Mobile phone: Motorola accompli008
The Motorola accompli008 was one of the first models that
were named ”smartphone”. It is a combination of a PDA and a
mobile phone, with the design being a cross of the two.
It features a normal GSM 900/1800 dual band connection,
GSM-data (9.6 kb/s) and GPRS data (40.2 kb/s using 3+1
slots). It supports J2ME and has a MIDP 1.0 profile. WAP and
e-mail protocols are also supported.
Its 2.6-inch touch display measures 54 x 40 mm and can
display 320x240 pixels in 4 grey tones. It sports 8MB Flash
memory, and 8MB RAM.
The whole unit is 98 x 60 x 28 mm and weighs 155 g.
In addition to the regular features of a mobile phone, like SMS,
WAP browsing and such, this phone also has many PDA-like
qualities like touch-screen, handwriting recognition, PCsynchronization and the ability to install new applications
through its java environment.
Figure 22 - Motorola
accompli008
The Motorola accompli008 costs around $499.
2.5 Comparison elements
In order to compare the different device types, some comparison properties have to be
defined. To compare across unit types, the following properties can be drawn out as
interesting elements.
•
•
•
•
•
•
•
•
•
Display size, resolution and colour
Sound
Processor capability, memory and storage
Network type and bandwidth
Ease of use
Battery
Application capabilities
Price
Size/Portability
The motivation for choosing exactly these properties are simply put that some of them are
the most relevant characteristics in a multimedia setting like screen and sound, while others
are more related to public interest, for instance price and size.
The comparison elements are formulated into evaluation criteria and the comparison will be
dealt with in chapter 13, where the actual evaluation of devices is made.
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PART II - PRESTUDY
Chapter 3 – Media player applications
This chapter presents some media player applications, predominantly ones that are available
for the Pocket PC operating system. The reason for this is that in the media player evaluation
in section 13.3, a Pocket PC device is used.
3.1 Media Players
Two of the most well-known media players, Windows Media Player and RealPlayer (now
known as RealOne Player) are available for both laptop and PDA platforms.
Naturally the laptop versions are more advanced and include many additional features as
well as being able to play media files. Another well-known media player, QuickTime, is as yet
only available for regular PC operating systems.
For PDAs there are some media player programs available that are specific for the PDA
format. Packetvideo and PocketTV are media player applications only available for the
Pocket PC OS, and Fireviewer and gMovie Player are only available for PalmOS.
As mobile phone units are not especially open systems at the moment, there aren’t really
many applications available for these except java applications for the Java enabled units.
The Nokia 9210i Communicator with its Epoc OS has got the RealOne Player media player
though, and thus there should be possibilities for other smartphones and units with this OS to
use RealOne Player once the developers get around to it.
A feature that separates media player applications into two classes is the ability or non-ability
to play streaming media. More specifically, a player can have no streaming abilities, pseudostreaming abilities or real streaming abilities [16].
Also it has to be stated that the media playing applications for devices like Pocket PC which
are less powerful than regular PCs, although looking much like and seemingly the same
application as for a full PC operating system, are quite downsized in comparison and lacks
many of the features the full versions possesses. For instance, both RealOne Player and
Windows Media Player are unable to accept anything else than media files, media redirection
files or Internet links which lead directly to the media file in question.
3.2 Windows Media Player
Windows Media Player is the standard media playing tool that comes
with the Pocket PC operating system, and is reminiscent of the more
advanced Windows Media Player for the full Windows operating
systems.
Windows Media Player supports the organization and playback of Windows Media content,
MP3 audio files, Windows Media Audio, Windows Media Video and streamed content in
Windows Media format using Windows Media protocols (http:// and mms://). For more details
of media compatibility with Windows Media Player, see appendix C. Note that the mms://
protocol is not related to the MMS messaging service.
This application is then streaming capable, although in a quite restricted manner. Streaming
of MP3 files is not supported, so that the only streamed content playable with Windows
Media Player is the Windows Media formatted content. It allows full screen display of video.
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PART II - PRESTUDY
This application in the portable device format only exists for Pocket PC.
3.3 RealOne Player
RealOne Player from RealNetworks is another popular media player
application, perhaps due to the fact that it was one of the first players
to offer true streaming to the public.
RealNetworks are showing that they are committing themselves to mobile media, with the
incorporation of RealOne Player in the Nokia 9210i (for the EPOC/Symbian OS), and also
after having made an agreement with Compaq that has lead to Compaq shipping all new
iPAQs with RealOne Player installed.
The RealOne Player for Pocket PC devices is a lightweight version optimized for resourceconstrained devices like the ones utilizing the Pocket PC operating system. RealAudio and
RealVideo programs can be streamed in real time over a wireless data connection, and
supports network types like IEEE 802.11b, GPRS, HSCSD, CSD, CDPD and 1XRTT.
RealAudio and RealVideo files can also be downloaded and played back locally. The
RealOne Player for the Pocket PC can be used on most Pocket PC devices [17].
3.4 QuickTime
At present QuickTime has no player application for handheld devices.
Only QuickTime applications for full PC operating systems like
Windows, Linux and MacOS exist. The question is how long
QuickTime can wait before releasing an application for mobile devices
as well.
Apparently, PVPlayer from Packetvideo is able to or will be able to play QuickTime files.
3.5 PacketVideo PVPlayer
PacketVideo has a streaming capable player for Pocket
PC devices that will allow users to watch movies and
listen to audio over a wireless connection, including
QuickTime format video.
According to PacketVideo, watching movie clips, catching the latest news and sports
highlights, checking traffic conditions, seeing your favorite music video, looking in on your
child at daycare, is all going to be possible on a Pocket PC using PVPlayer as wireless
networks continue to evolve [18].
PVPlayer can decode and play MPEG4 video streamed over both wireless or regular
networks for viewing on mobile devices, at data rates from as low as 9.6 kb/s to more than
384 kb/s. It is specially optimized for incorporation into video-enabled phones, PDAs,
Smartphones, laptops and other mobile devices with limited processing power, limited
battery life and varied display sizes.
PVPlayer is compliant with open standards, including MPEG4, IETF, and ITU. PVPlayer will
detect, localize and conceal errors that occur during wireless transmission, while supporting
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PART II - PRESTUDY
true MPEG4 compliant scalability, which is required for bandwidth-efficient wireless
distribution.
3.6 IceStream
I was lucky enough to find a company in the local area that was
involved with multimedia for mobile devices. Mobile Media had
an office in Trondheim, and I got to visit their offices and have a
discussion with one of their project managers, Øystein Vik,
about their products and related matters.
Their main business concept is production, delivery and access of content on the Internet for
use with wireless mobile devices. They are also developing platforms that enable access to
rich and interactive multimedia content. In addition to applications concerning animation, they
had also been involved with SMS services and serving downloads for java-enabled
telephones [19], [20].
The application that caught my attention though, was a visual low bit rate streaming
application for PDA’s that worked on existing GPRS, and even on HSCSD networks. It was
described as streaming motion, rather than streaming video, as the algorithms compressing
the visual images worked in a very different way from the typical MPEG way of doing things.
Unlike other video streaming applications announced to date, this solution does not require
3G networks or considerable processing capability.
This method was based on
capturing contour information
and drawing surfaces and
regions on screen, and the
data transferred was more
vector-based than bitmap
based, as is the case with
regular video media. Figure
23 shows an example of how
a converted video picture
would look in IceStream.
Figure 23 - Conversion from video picture (left) to
IceStream format
As stated on Mobile Media’s web site: “The extremely high video compression ratio is
achieved by combining advanced image analysis techniques, where visually important edge
and region information is detected and enhanced. Important features such as shadow
information are retained and less important information is discarded.”
The IceStream Motion Server runs on standard Intel hardware platforms and converts the
raw video signal from camera or video storage systems into a highly compressed video
stream that can be transmitted to a client over virtually any communication channel, e.g.
GSM, HSCSD, CDMA, GPRS or WLAN.
At the moment the technology is able to send video with the following characteristics:
A monochrome image stream of 80x60 pixels, at 10 frames per second (fps) using 5 kb/s
data rate, or a monochrome image stream of 160x120 pixels, at 10 fps using 10-20 kb/s.
Sound is also possible to send, which means an additional 13 kb/s, using a version of GSM
audio coding.
As is shown here, the picture quality is not up to the standard of some other applications, but
requires far less network and processing resources at the client side.
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Figure 33 in section 8.1.3 shows how this technology works on a PDA.
At the moment this technology works on PDA’s, but a goal for the future is to make
applications for common-use mobile phones using this technology. This of course depends
on the mobile phones getting more powerful processing capabilities. A version of the player
is available for J2ME mobile phones, but due to limitations on the mobile phones and on the
java runtime environment these are not very well suited for this purpose. Vik said that other
challenges Mobile Media is working on are the possibility of adding colour information to the
streamed data, and also to improve the adaptive solutions regarding actual data throughput
on the network.
According to Vik, the Java-enabled phones of today could handle only 1-2 frames per second
of picture and had no sound streaming capabilities. Therefore more powerful handsets have
to become available before this technology can make its mark on the mobile phone class of
devices.
3.7 Pocket DivX
The Pocket DivX Player is a FREE Open Source multifunction video and audio player for the
Pocket PC platform that can play DivX, OpenDivX, MPEG4, MPEG1 videos and MP3 audio
[21].
This application is available in different versions for different Pocket PC devices.
3.8 PocketTV
PocketTV [22] by MpegTV is a media playing application available for Pocket PC and
Handheld PC operating systems. It can play back standard MPEG1 video files, and seems to
be one of few players with this feature among video players for Pocket PC.
PocketTV is capable of both local storage playback and streaming of MPEG video files. The
streaming is done using standard internet protocols such as http, provided that the device
has a wireless network connection that supports the necessary bandwidth i.e. the bitrate of
the MPEG file that is to be streamed.
3.9 PhotoSuite
PhotoSuite for PalmOS is an application that comes bundled with new Palm devices. The
MGI PhotoSuite Mobile Edition allows users to store, view, and share photos and videos on
their Palm OS handheld. Loading of media to a Palm device is done by transferring files from
a PC to the Palm using synchronisation. The pictures and video are then converted to
formats suitable for PalmOS. This application is probably more suitable for pictures than for
video clips, as watching video really pushes the limits of both the OS and the processor on a
PalmOS device.
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3.10 Other Media player applications
There are a number of other media player applications on the market, which will not be
presented thoroughly in this thesis. This is because of lacking features, small amount of
information available, or that content for the media player is scarce.
Emblaze
Emblaze develops commercial mobile media solutions for wireless carriers, content providers
and handset manufacturers. No application is available for download yet [23].
Fireviewer
Fireviewer is a streaming capable media player for PalmOS that claims to be able to play all
types of rich content, from text to technical documentation to live video feeds [24].
Tealmovie
TealMovie is a Palm multimedia system which enables any model Palm handheld to become
a player of video and animation. TealMovie supports smooth playback up to 25 frames per
second, high-quality full screen color or grayscale imagery, WAV file playback, and
synchronized sound playback capability. An included Windows converter program creates
TealMovie-format files from standard AVI and WAV files [25].
ActiveSky
ActiveSky is a media publishing and delivery platform, enabling the deployment of rich
graphical user-interfaces and multimedia applications on wireless devices. The platform
adopts the SMIL 2.0 standard, simplifying the delivery of online services to mobile users.
Apparently, ActiveSky is only capable of picture streams, and not video streams [26].
gMovie
gMovie Player is an application for playback of color video, animation and still image files on
any Palm handheld [27].
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Chapter 4 – Network technologies
The network media and protocols used to carry the data are of great importance. There are
quite a number of existing systems as well as systems that are in development. The
networks that are relevant for this paper are wireless networks, and the networks that exist in
this category are often divided into two main groups: mobile (phone) networks, and other
wireless networks (i.e. IEE 802.11b and Bluetooth). An even more granular division that will
be used in this thesis is into the classes WWAN, WLAN and WPAN.
4.1 WWAN, WLAN, WPAN
There are several fundamental differences between wireless network systems, such as
range, price, abilities, primary role, power consumption etc. One of the most important, if not
the most important, is range. This is one field which is often used (combined with role) to
differentiate between wireless technologies.
A common practice is to import network (fixed connection) definitions like WAN (Wide Area
Network) and LAN (Local Area Network), and to append W (for wireless) to them. Also a less
common term PAN is used, (Personal Area Network), and must also be appended with W.
Figure 24 gives an understanding of how the different network technologies can be grouped
according to range.
WWAN
R
x1
km
WLAN
WPAN
Rx
0
10
m
R x 10m
Bluetooth, IrDA
etc.
IEEE 802.11 etc.
GSM, GPRS, UMTS
Figure 24 - WWAN, WLAN and WPAN ranges
This gives us a segmented view of wireless technologies. WWAN technologies would include
mobile phone networks such as GSM, GPRS, and UMTS. These are characterised by long
range and high power consumption. WLAN technologies would include 802.11b, HiperLAN
etc. These are characterised by medium power and medium range. Finally WPAN
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PART II - PRESTUDY
technologies would include Bluetooth, IrDA, HomeRF, which have limited range and small
power consumption.
4.2 Mobile networks (WWAN)
According to De Vriendt et al. [30], during the first half of 2002, the number of mobile phone
users will reach 1 billion. This technical revolution has been realized through a continuous
evolution of standards and products development trying to keep an optimum level of
performance. This evolution started in the early 90s with the replacement of the analogue
mobile network by the digital one, and is still going on today with the development and
deployment of the third generation (3G) of mobile networks. After leaving the circuit-driven
networks we now start to roll out the packet-driven networks through intermediate overlay
networks like GPRS, followed in the coming years by full-fledged all-IP networks.
Global System for Mobile Communications (GSM) now accounts for 66 percent of the world’s
total market [30]. This market share is only likely to increase as major time-division multiple
access (TDMA) actors have started the move to GSM.
The reason behind the TDMA migration to GSM is not only technical but also financial thanks
to GSM’s huge economy of scale. Another technological consolidation is occurring with 3G
mobile technologies, where Universal Mobile Telecommunications System (UMTS) is the
chosen evolution for all GSM networks, as well as for the Japanese Personal Digital Cellular
(PDC) network. As a result UMTS is chosen as 3G technology by about 85 percent of mobile
operators.
Until now, the increase of mobile phone users has been almost purely driven by the good old
voice services. It is only in recent years that data has started to contribute at a considerable
level to the revenues of mobile operators, reaching about 10 percent in the second quarter of
2001 for advanced operators like NTT DoCoMo (i-Mode) and Orange (Short Message
Service, SMS) [29]. Voice mobility is becoming a commodity for end users, and the market is
demanding new applications. Operators currently face the challenge of performing a cultural
transition from a voice-only service offering toward offering new applications. This transition
is required to keep their revenues growing.
The 2G technology GSM has been around for
a number of years, the 2.5G technology
GPRS was introduced quite recently, while
3G technologies like UMTS are being
developed and prepared for release to the
general public.
TDMA
GSM
Figures 25 to 27 are an indication of where in
the timeline for mobile technology we are right
now. Although most users still use 2G
technologies, the technology is on its way
from 2.5G to 3G very soon. The issue of
technology transition by the user base will be
covered later in chapter 7.
These figures, which are taken from different
sources [28], [30], [31], also point out that
there is not a total agreement in the industry
on the way the evolution has come to pass.
The definition of the different generations and
on the different technologies’ heritage and
EDGE
GPRS
PDC
W-CDMA
CDMA
2000
CDMA
MC1x
2G
Evolved 2G, 2.5G
3G
9.6 - 14.4 kbps
64 - 144 kbps
384 kbps - 2 Mbps
Figure 25 - Mobile network evolution
according to Elsen et al. [31]
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PART II - PRESTUDY
further development is not always in coherence either.
Multiradio 3G Network
TDMA
TDMA
GSM/
GPRS/
EDGE
GSM/
GPRS
GSM
GPRS/
EDGE
PDC
UMTS
GSM
W-CDMA
PDC
W-CDMA
IS95-A
CDMA
IS95-B
CDMA
CDMA
2000
CDMA
CDMA
2000 1x
2G
2.5G
3G
2G
First steps to 3G
according to De Vriendt et al. [30]
CDMA
2000
1xEV-DV
CDMA
2000
1xEV-DO
3G Phase 1
Evolved 3G
according to Myllymäki [28]
An example of incoherence in the industry is whether EDGE is a 3G technology or not. Some
claim it is only a further development of GPRS, and therefore is a 2,5G technology, while
Nokia for instance, put EDGE in the 3G category. The tendency seems to be that commercial
groups that produce equipment like network infrastructure and handsets consider EDGE to
be 3G, while more academic environments mean that EDGE is 2,5G.
2 Mbps
Figure 28 is a diagram that shows
the data rates of the 2G
technologies GSM and HSCSD,
the 2,5G technologies of GPRS
and EDGE and the 3G technology
of UMTS.
400
Theory
EDGE
Practice
300
Kbps
200
GPRS
100
GSM
2G
GPRS
HSCSD
HSCSD
Unfortunately it appears that the
networks do not achieve the
theoretical data rates, as practical
use of the two technologies
HSCSD and GPRS have shown.
UMTS
2,5 G
3G
Generation
Figure 28 - Data rates for 2G, 2,5G and 3G mobile networks
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4.3 Second generation mobile networks
This section will present some of the different second generation networks that exist, and
then some of the services available for these networks. As GSM is the system used here in
Europe, this thesis mainly concentrates on that technology. The sections 4.3.1 to 4.3.4 are
concerning network systems, while sections 4.3.5 to 4.3.7 are about data services for the
GSM network system.
4.3.1 Global System for Mobile Communications (GSM)
Firstly, it should be pointed out that GSM is both used as a term meaning a family of mobile
technologies and as a term involving one specific mobile technology. The GSM family of
wireless communication platforms include today's GSM, GPRS, EDGE and UMTS (3GSM).
Today's second-generation GSM networks deliver high quality and secure mobile voice and
data services (such as SMS Messaging) with full roaming capabilities across the world.
Today's GSM platform is a very successful wireless technology and perhaps a story of global
achievement. In less than ten years after the first GSM network was commercially launched,
it became the world's leading and fastest growing mobile standard, spanning over 174
countries. GSM was first introduced in 1991, and today, GSM technology is in use by more
than one in ten of the world's population and growth continues to soar with the number of
subscribers worldwide expected to surpass one billion by the end of 2003 [32].
To make a pan-European digital cellular system, the Groupe Spécial Mobile (GSM) was
formed in 1982 by the Conférence Européenne des Postes et des Télécommunications
(CEPT). In 1989, the European Telecommunications Standards Institute (ETSI) made the
GSM specifications, and these specifications have recently been transferred to the 3G
Partnership Project (3GPP) [30].
GSM commercial service was started mid-1991, although handsets were not readily
available before 1992. In 1993, there were 36 GSM networks in 22 countries, including nonEuropean countries such as Australia and South Africa. Today, there are more than 470
GSM operators in 174 countries, and by January 2002 there were 646 million users. [30]
GSM allows up to eight users to share a single 200 kHz radio channel by allocating a unique
time slot to each user. This technique is called TDMA, and is explained further in section
4.3.2, called TDMA. GSM is used in the 900 and 1800 MHz bands all over the world except
North America (1900 MHz band). Eventually, new frequencies will be used in the 450 and
850 MHz bands. Since the beginning, GSM has offered SMS, a connectionless packet
service limited to transmitting text messages containing less than 160 characters. Data
transfer is also made possible using a service called circuit-switched data (CSD), which
offers throughput up to 14.4 kb/s. These limitations led to the standardization of the High
Speed Circuit Switched Data (HSCSD) and General Packet Radio Service (GPRS), which
are covered in sections 4.3.7 and 4.4.1.
The GSM EDGE Radio Access Network group of 3GPP now handles further evolution of the
GSM standard. This group covers in particular the connection of GSM/EDGE to future 3G
core networks and support of real-time services.
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4.3.2 TDMA
TDMA is Short for Time Division Multiple Access, a technology for delivering digital wireless
service using time-division multiplexing (TDM). TDMA works by dividing a radio frequency
into time slots and then allocating slots to multiple calls. In this way, a single frequency can
support multiple, simultaneous data channels. The TDMA technique is employed by the GSM
digital mobile system. TDMA can also refer to a particular implementation of TDMA,
specifically, the IS-136 standard commonly used in North and South America.
Recent developments indicate that the TDMA community is moving toward GSM. AT&T
Wireless was the first to announce this decision in November 2000. Since then, Cingular
Wireless in the United States and other major Latin American TDMA operators have
announced their preference for GSM [30].
These new GSM networks will look to integrate GPRS and EDGE. Deployment of UMTS will
require additional spectrum and be limited to 3G operators gaining new frequencies.
4.3.3 CDMA
Short for Code-Division Multiple Access, CDMA is a digital cellular technology that uses
spread-spectrum techniques. Unlike competing systems, such as GSM, which use TDMA,
CDMA does not assign a specific frequency to each user. Instead, every channel uses the
full available spectrum. Individual conversations are encoded with a pseudo-random digital
sequence. Spread spectrum technology has been used in military applications for a very long
time. In the mid-80s, the military in the USA declassified this technology, and it was tested for
cellular telephony applications [30].
The spread-spectrum-based code-division multiple access (CDMA) standard, was approved
in July 1993 by the Telecommunications Industry Association (TIA). In 1995, commercial
CDMA networks opened, but by mid-1998 had attracted only 9 million users. Things have
improved since that time though, with around 100 million users today, mainly in the Americas
(55 million) and Asia (40 million). CDMA is now called cdmaOne to differentiate it from 3G
CDMA systems.
With CDMA, up to 64 users share the same 1.25 MHz channel. Attaching a pseudo-random
code to each user allows decoders to separate traffic at each end. All base stations transmit
the same pseudo-random code with a time offset, and therefore they must remain
synchronized. CDMA is used in the 850 MHz and the 1900 MHz bands.
IS-95A, the first version of CDMA, offers data throughput limited to 14.4 kb/s, just like GSM.
An improvement, IS-95B were specified in June 1997. By assigning up to seven
supplementary codes in addition to the fundamental code, data rates up to 64 kb/s are
possible. Some Asian operators have started to implement IS-95B services.
cdmaOne is the basis for the cdma2000 systems, but the WCDMA system used in UMTS,
although using a similar coding technique, is a quite different standard and is not directly
related to the original CDMA systems.
4.3.4 PDC
PDC is the Japanese TDMA-based standard operating in the 800 and 1500 MHz bands.
PDC hosts the most convincing example of mobile Internet, i-Mode. i-Mode has already
gathered over 30 million subscribers thanks to a large service offering and an excellent
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business model including billing on data volume and a revenue sharing arrangement
between network and content owners [30].
Congestion of the PDC system has urged NTT DoCoMo to replace it rapidly with a 3G
system.
4.3.5 Short Message Service (SMS)
The Short Message Service (SMS) is the ability to send and receive text messages to and
from mobile telephones. The text can comprise of words or numbers or an alphanumeric
combination. SMS was created as part of the GSM Phase 1 standard. The first short
message is believed to have been sent in December 1992 from a personal computer to a
mobile phone on the Vodafone GSM network in the UK. Each short message is up to 160
characters in length (when Latin alphabets are used).
4.3.6 WAP
WAP is short for Wireless Application Protocol, a specification that allows users to access
information instantly via handheld wireless devices such as mobile phones, pagers, two-way
radios, smartphones and communicators. The WAP initiative was started by Unwired Planet,
Motorola, Nokia and Ericsson [13].
WAP supports most wireless networks, including but not limited to CDPD, CDMA, GSM,
GPRS, PDC, TDMA, DECT. WAP is supported by all operating systems. Ones specifically
engineered for handheld devices include PalmOS, EPOC, Windows CE, FLEXOS, OS/9, and
JavaOS.
WAPs that use displays and access the Internet run what
are called microbrowsers, browsers with small file sizes that
can accommodate the low memory constraints of handheld
devices and the low-bandwidth constraints of a wirelesshandheld network. Figure 29 indicates what a WAP browsing
session can look like.
Although WAP supports HTML and XML, the WML language
(an application of XML) is specifically devised for small
screens and one-hand navigation without a keyboard. WML
is scalable from two-line text displays up through graphic
screens found on items such as smart phones and
communicators. WAP also supports WMLScript. It is similar
to JavaScript, but makes minimal demands on memory and
CPU power because it does not contain many of the
unnecessary functions found in other scripting languages.
Figure 29 - WAP browsing
WAP has had a limited commercial success as yet, perhaps
due to expensive and slow connections, in addition to limited available content. However, the
development and market introduction of faster networks may spark new life into the
technology. All new mobile phone handsets released by the major manufacturers feature
WAP browsers.
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4.3.7 High Speed Circuit Switched Data (HSCSD)
High Speed Circuit Switched Data (HSCSD) is an enhancement of data services (Circuit
Switched Data - CSD) of all current GSM networks. It allows you to access non-voice
services at 3 times faster, which means subscribers are able to send and receive data from
their portable computers at a speed of up to 28.8 kb/s; this is currently being upgraded in
many networks to rates of and up to 43.2 kb/s. The theoretical maximal data transfer speed
is 57.6 kb/s, but in use this transfer rate does not occur.
The HSCSD solution enables higher rates by using up to four communication channels,
allowing subscribers to enjoy faster rates for their Internet, e-mail, calendar and file transfer
services. HSCSD allows users to access their company LAN, send and receive e-mails and
access the Internet whilst on the move. HSCSD is currently available to 90 millions
subscribers across 25 countries around the world.
HSCSD is offered to subscribers using either voice terminals that support the feature, or a
PCMCIA portable computer card, with a built in GSM phone. This means that connection of a
HSCSD mobile phone or a PCMCIA card with a computer can turn notebook computers and
other portable devices into a mobile networking device with the ability to transfer data at
HSCSD speeds, as well as make voice calls on the computer/portable device.
The HSCSD service is particularly valuable for users who wish to access the Internet, or their
office Intranet, access their mail, or access files stored elsewhere. The service allows a
subscriber who is out of office, or who travels abroad in one of the countries in which HSCSD
roaming is available, to connect to a local ISP, or directly to one's office, using the cellular
device rather than a fixed line.
As mentioned, HSCSD enables higher rates, but like CSD it is circuit-based. Therefore, it is
inherently not efficient for bursty traffic. This weakness of HSCSD has contributed to only
around 30 operators having introduced it so far. Most operators use or will introduce GPRS
instead. A positive effect of the circuit-based technique though, is that once a connection is
established, the data capacity will be constant through the whole duration of the connection,
as channels that are allocated are not lost until disconnection.
4.4 2,5G - Evolved second generation mobile networks
A further development of mobile networks from the basis that is the second generation
mobile networks has lead to a group of network standards that has gotten the name 2,5G.
This indicates that they are positioned between the 2G and the 3G systems in capabilities.
4.4.1 General Packet Radio Service (GPRS)
The General Packet Radio Service (GPRS) is a non-voice service that allows information to
be sent and received across a mobile telephone network. It supplements today's circuit
switched data services (CSD and HSCSD) and Short Message Service (SMS).
General Packet Radio Services (GPRS) is a packet-based wireless communication service
that have promised data rates from 56 up to 171 kb/s and continuous connection to the
Internet for mobile phone and computer users. These higher data rates could allow users to
take part in video conferences and interact with multimedia Web sites and similar
applications using mobile GPRS handheld devices as well as notebook computers
connected to a GPRS unit.
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In theory, packet-based service should cost users less than circuit-switched services since
communication channels are being used on a shared-use, as-packets-are-needed basis
rather than dedicated only to one user at a time. It should also be easier to make applications
available to mobile users because the faster data rate means that middleware currently
needed to adapt applications to the slower speed of wireless systems will no longer be
needed. Mobile users of a virtual private network (VPN) will be able to access the private
network continuously rather than through a dial-up connection.
GPRS will also complement Bluetooth, a standard for replacing wired connections between
devices with wireless radio connections, which is presented later in section 4.6.3. In addition
to the Internet Protocol (IP), GPRS supports X.25, a packet-based protocol that is used
mainly in Europe. GPRS is an evolutionary step toward Enhanced Data GSM Environment
(EDGE) and Universal Mobile Telephone Service (UMTS).
Because GPRS is an overlay technology on GSM, the investments necessary to upgrade the
networks are not very high. The drawback of this semi-step towards 3G is that the data
transfer speeds will not be as high as many would have hoped.
What does the introduction of GPRS mean?
As a convergence of mobile telecommunications and data networking, GPRS brings Internet
Protocol (IP)-based services to the mobile mass market, as GPRS handsets are given an IP
address when connecting to their mobile service provider. For instance, GPRS is a good
bearer of services based on Wireless Application Protocol (WAP).
General Packet Radio Service is a milestone on the road to 3G and All-IP providing packetswitched data, primarily for GSM and 2G networks. The information is transmitted in short
bursts of data over an IP-based network. With a GPRS-enabled mobile phone, a user can be
continuously connected to data networks and access information and entertainment services.
Services are received faster than with GSM phones and GPRS makes WAP services faster
and more enjoyable to use.
Key features of GPRS
Speed: Theoretical maximum speeds of up to 171.2 kb/s are achievable with GPRS using all
eight timeslots at the same time. This is almost three times as fast as the data transmission
speeds possible over today's fixed telecommunications networks (if compared to single line
ISDN) and ten times as fast as standard Circuit Switched Data (CSD) services on GSM
networks. By allowing information to be transmitted more quickly, immediately and efficiently
across the mobile network, GPRS may well be a relatively less costly mobile data service
compared to SMS and Circuit Switched Data.
Immediacy: GPRS facilitates instant connections whereby information can be sent or
received immediately as the need arises, subject to radio coverage. No dial-up modem
connection is necessary. This is why GPRS users are sometimes referred to be as being
"always connected". Immediacy is one of the advantages of GPRS when compared to Circuit
Switched Data. High immediacy is a very important feature for time critical applications such
as remote credit card authorization where it would be unacceptable to keep the customer
waiting for a dial-up connection.
New and better applications: GPRS facilitates several new applications that have not
previously been available over GSM networks due to the limitations in speed of Circuit
Switched Data (9.6 kb/s) and message length of the Short Message Service (160
characters). GPRS will fully enable the Internet applications we are used to on our desktops
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from web browsing to chat over the mobile network. Other new applications for GPRS could
include file transfer and home automation - the ability to remotely access and control inhouse appliances and machines [33].
To use GPRS, users specifically need:
•
•
•
•
A mobile phone or terminal that supports GPRS
A subscription to a mobile telephone network that supports GPRS
Use of GPRS must be enabled for that user. Automatic access to the GPRS may be
allowed by some mobile network operators, others will require a specific opt-in
A destination to send or receive information through GPRS. Whereas with SMS this
was often another mobile phone, in the case of GPRS, it is likely to be an Internet
address, since GPRS is designed to make the Internet fully available to mobile users
for the first time. From day one, GPRS users should be able to access any web page
or other Internet applications- providing an immediate critical mass of uses.
According to VOCAL there are four coding schemes for GPRS, CS1 to CS4 [34]. CS1 offer
the lowest throughput but the best error detection, while CS4 provide the highest throughput
but have little or no error correction features. Table 3 shows the different data rates that the
coding techniques offer.
Data Rate
1 Timeslot
8 Timeslots
CS1
CS2
CS3
CS4
9.05 kb/s
13.4 kb/s
15.6 kb/s
21.4 kb/s
72.4 kb/s
107.2 kb/s
124.8 kb/s
171.2 kb/s
Table 4 - Data Rate for GPRS
Summary of GPRS
To sum up; GPRS, which keeps the GSM radio modulation, frequency bands, and frame
structure, is designed around a number of guiding principles [30]:
• Always on: Allows sending or receiving data at any time
• High bit rates: An actual bandwidth roughly equivalent to a wireline modem
• Separate allocation of uplink and downlink channels
• Simultaneous voice call and data transfer
• Billing based on volume of data transferred
In September 2001 around 100 operators, including several American operators, deployed
GPRS.
The emerging technology of Enhanced Data Rate for Global Evolution (EDGE) improves
GPRS by introducing a new radio modulation scheme that triples the bandwidth offered by
GPRS.
The fact that newer network types are being developed may mean that GPRS will have a
relatively short lifespan. If network providers are successful in promoting and recruiting users
to more advanced networks, there may not even be a second generation of GPRS handsets.
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4.4.2 MMS (Multimedia Messaging Service)
MMS is a relatively new standard that has been defined for use in advanced mobile
terminals. This service concept has been derived from SMS, and gives the possibilities for
non-realtime transmission of different types of multimedia content.
With MMS, it is possible to combine conventional text messages with richer content types
such as photographs, images, animation, voice messaging and, eventually, video clips.
An example of MMS messages content and composing will be made in chapter 14, using the
Sony Ericsson MMS Composer tool.
4.4.3 i-Mode
i-Mode is NTT DoCoMo's packet-based mobile
Internet access system. NTT DoCoMo is a leading
mobile phone service provider in Japan. This network
standard has become very popular in Japan. i-Mode
offers near always-on connectivity, limited www-access
through cHTML (compact HTML), email, and access to
other services suited to this client technology. This
system was introduced about at the same time as WAP
in Europe and has similar functionality. The mobile
phone handsets are more advanced than regular GSM
phones, as with WAP handsets compared to standard
GSM handsets. But in contrast to WAP, i-Mode has
definitely catched on and has become a huge success
for the mobile service providers. Figure 30 shows an
example of a i-Mode capable mobile phone.
Figure 30 - i-Mode mobile phone
First introduced in 1999, i-Mode was the world's first smart phone for Web browsing. The iMode wireless data service offers colour and video over many phones. Its mobile computing
service enables users to do telephone banking, make airline reservations, conduct stock
transactions, send and receive e-mail, and have access to the Internet. As of early 2000, iMode had an estimated 5.6 million users. By January 2002, this figure had risen to 30 million.
Recently, i-Mode services have been introduced in the Netherlands and Germany as well.
4.5 3G – Third generation mobile networks
3G - or 3rd generation - technology is a general term for the next generation of mobile
communications, which promises to greatly enhance user services. 3G mobile devices and
new types of services will bring high-speed, real-time connectivity to wireless
communications, regardless of time and place.
The notion of 3G became evident with the need for greater capacities, more frequencies and
higher data transfer rates. The target was initially to agree upon a truly international
standard, although this has not been completely successful.
3G is an International Telecommunication Union (ITU) specification for the third generation of
mobile communications technology. 3G promises increased bandwidth, up to 384 kb/s when
a device is stationary or moving at pedestrian speed, 128 kb/s in a car, and 2 Mb/s in fixed
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applications. 3G will work over wireless air interfaces such as GSM, TDMA, and CDMA. The
new EDGE air interface has been developed specifically to meet the bandwidth needs of 3G.
3G builds on the already available GPRS system in that it seeks to further implement the use
of IP-traffic for mobile wireless devices. One could also claim that 3G really is the standard
that GPRS tries to emulate, only that GPRS will be less capable yet quicker to implement
given the existing GSM systems.
In many ways 3G systems will share the characteristics of GPRS, in that both systems are
packet based and always online. Therefore much of what has been said about the basic
concept of GPRS also goes for 3G technology.
Services
It is expected that no single 3G application will dominate the market. High-speed content like
video on demand, multimedia and always-on Internet access are just a few of the
possibilities. According to Nokia it is anticipated that MMS (Multimedia Messaging Service)
will be one of the first successful services on the market.
Technologies
GPRS is an important step towards 3G as it introduces and provides always-on services to
users. According to Nokia, 3G users will be best served by EDGE, the technology for existing
frequencies, together with WCDMA, the technology for new UMTS frequencies. It is
expected that practically all GSM and TDMA operators will implement EDGE when data and
multimedia services become more popular and more capacity is required in the network.
EDGE and WCDMA will then be used in parallel in mobile networks for a number of years to
come.
Availability
3G network solutions are beginning to be rolled out in Europe, although the pace of the
implementation has apparently slowed quite a bit the last year. The first WCDMA and EDGE
networks are expected to be launched commercially during the second half of 2002, with
EDGE being introduced before WCDMA in the Americas, and WCDMA being introduced
before EDGE in Europe [35].
3GPP
3GPP (Third Generation Partnership Project) is a collaboration agreement that brings
together standards bodies for developing the standards for WCDMA as well as GSM/EDGE
technologies. It started developing the WCDMA standards in early 1999 and the 3GPP
Release 1999 standard was the first release introducing the WCDMA air interface and radio
access network, with more releases following. GSM/EDGE standards have been developed
as part of the project since 2001.
3G network standards
As mentioned earlier, the original intention was to define an international standard that would
be interoperable across the world. But this has not been entirely successful, and there are
now two main proposed systems for 3G, in addition to EDGE, which despite being approved
as a 3G system, could be considered a simpler evolution of existing GSM/GPRS systems
described earlier. The two proposed systems are UMTS and cdma2000, which are presented
after EDGE.
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3G units
The first 3G WCDMA/GSM mobile phones, by some named imaging phones, are expected to
be available during the second half of 2002. Nokia also plans to introduce EDGE handsets
before the end of 2002. This company also expects all GSM/GPRS and WCDMA terminals to
include EDGE functionality by the end of 2004. Additionally, PCMCIA and CompactFlash
computer network cards will also appear for direct computer connection.
Why would people use a 3G phone?
The concept of mobile voice calls will radically change as multimedia capabilities are added.
For example, it will be possible to share data and images simultaneously with users who are
connected with a voice or video connection, leading to richer and hopefully more effective
communications.
4.5.1 EDGE
EDGE (Enhanced Data rates for GSM/Global Evolution) is a standardised set of
improvements to the GSM radio interface. It defines new modulation and radio protocols that
bring higher maximum data rates (384 kb/s) than the GSM wireless service and increased
spectral efficiency. EDGE is applicable to both GPRS traffic and circuit-switched data traffic
(CSD and HSCSD). EDGE can be implemented on the existing GSM frequency bands.
The EDGE upgrade will start in 2002, mostly in the United States during the first phase.
4.5.2 UMTS
UMTS (Universal Mobile Telecommunications Service) is a so-called third-generation (3G),
broadband, packet-based transmission of text, digitized voice, video, and multimedia at data
rates up to 2 Mb/s that will offer a consistent set of services to mobile computers, wireless
devices and phone users no matter where they are located in the world.
Based on the Global System for Mobile (GSM) communication standard, UMTS, endorsed by
major standards bodies and manufacturers, is the planned standard for mobile users around
the world by 2002. Once UMTS is fully implemented, computer and phone users can be
constantly attached to the Internet as they travel and, as they are using a roaming service,
have the same set of capabilities no matter where they travel. Users will have access
through a combination of terrestrial wireless and satellite transmissions. Until UMTS is fully
implemented, users can have multi-mode devices that switch to the currently available
technology (such as GSM 900 and 1800) where UMTS is not yet available.
Today's cellular telephone systems are mainly circuit-switched, with connections always
dependent on circuit availability. The introduction of GPRS have given mobile networks
packet-switched connection, using the Internet Protocol (Internet Protocol), something that
UMTS will build upon in the future. This packet-switched connection means that a virtual
connection is always available to any other end point in the network. It will also make it
possible to provide new services, such as alternative billing methods (pay-per-bit, pay-persession, flat rate, asymmetric bandwidth, and others). The higher bandwidth of UMTS also
promises new services, such as high quality video conferencing.
It should be noted that as Wideband CDMA (WCDMA) will be the dominant technology used
in UMTS, the terms UMTS and WCDMA is often used about one another.
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UMTS licences
By the end of 2001 there were approximately 100 UMTS licenses worldwide. All the global
operators have selected WCDMA as their choice for 3G technology and Nokia expects that
by 2006, over 85% of mobile subscribers will be GSM/EDGE/WCDMA users [28].
UMTS Modes
UMTS is composed of two different but related modes [30],[36]:
•
•
CDMA-direct spread: Wideband CDMA (WCDMA), also called frequency division
duplex (FDD)
CDMA-TDD (time-division duplex)
Technical specification work on FDD and TDD standardization is being done within the
3GPP. The edition of specifications is phased in different releases:
•
3GPP release 3 specifications, formerly called release ’99, define FDD and TDD
modes, and are based on asynchronous transfer mode (ATM) in the radio access
network. Release 3 was actually issued in March 2000 and became stable in June
2001.
•
3GPP release 4 specifications define a new version of TDD and FDD mode
improvements. Release 4 was frozen in March 2001.
•
3GPP release 5 specifications shall include IP-based transport within the radio
access network. Release 5 was scheduled for March 2002.
FDD mode is considered the main technology for UMTS. FDD mode is derived from CDMA
and also uses pseudo-random codes. Separate 5 MHz carrier frequencies are used for the
uplink and downlink, respectively, allowing an end user data rate per channel of up to 384
kb/s (2 Mb/s per carrier). Later on, high-speed downlink packet access (HSDPA) will allow
downlink data rate transmission to increase. FDD allows the operation of asynchronous base
stations.
The TDD mode likely to be deployed is called timedivision-synchronous code-division
multiple access (TD-SCDMA). TD-SCDMA operates with 1.6 MHz carrier spacing instead of
5 MHz for the other wideband standards. It allows end-user data rates up to 2 Mb/s in
optimal conditions.
NTT DoCoMo commercialized a 3G service, called FOMA, in October 2001. Elsewhere, the
installation of the first UMTS system (FDD mode only) will start in 2002, and marketing of
services during 2003.
4.5.3 cdma2000
Technical specification work for cdma2000 standardization is being done within 3GPP2 in the
following steps [30]:
1. cdma2000 1x, which is an evolution of cdmaOne, supports packet data service up to
144 kb/s.
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2. cdma2000 1xEV-DO introduces a new air interface and supports high-data-rate
service on downlink. It is also known as high rate packet data (HRPD). The
specifications were completed in 2001. It requires a separate 1.25 MHz carrier for
data only. 1xEV-DO provides up to 2.4 Mb/s on the downlink (from base station to
terminal), but only 153 kb/s on the uplink. Simultaneous voice over 1x and data over
1xEV-DO is difficult due to separate carriers.
3. cdma2000 1xEV-DV, which will introduce new radio techniques and an all-IP
architecture for radio access and core network. The completion of specifications is
expected in 2003. It promises data rates up to 3 Mb/s.
SK Telecom from Korea was the first operator to launch cdma2000 1x in October 2000.
Since that time, only a few operators have announced cdma2000 1x service launches. Some
operators recently announced setting up cdma2000 1xEV-DO trials.
4.6 Wireless network technologies (WLAN & WPAN)
Other wireless network technologies will be discussed in the following sections, both WLANs
and WPANs are presented.
4.6.1 The 802.11 series
802.11 refers to a family of specifications developed by the IEEE for wireless LAN
technology. 802.11 specifies an over-the-air interface between a wireless client and a base
station or between two wireless clients. The IEEE accepted the specification in 1997.
This technology for WLAN use is based on installing access points for wireless devices
around a building or area so that users has access to the network there.
Each radio may act, depending on software, as a hub or for computer-to-computer
transmission, but it's much more common that a WLAN installation uses one or more access
points, which are dedicated stand-alone hardware with typically more powerful antennae.
The access point often includes routing, DHCP server, Network Address Translation (NAT)
and other features necessary for small to large site operation. Similar to access points are
residential gateways, a new class of device, which offers similar features but without the
advanced management required for corporate networks or high-traffic installations.
The IEEE 802.11 specifications are wireless standards that specify an "over-the-air" interface
between a wireless client and a base station or access point, as well as among wireless
clients. The 802.11 standards can be compared to the IEEE 802.3 standard for Ethernet for
wired LANs. The IEEE 802.11 specifications address both the physical and Media Access
Control layers and are tailored to resolve compatibility issues between manufacturers of
Wireless LAN equipment.
There are several specifications in the 802.11 family:
•
802.11 - applies to wireless LANs and provides 1 or 2 Mb/s transmission in the 2.4 GHz
band using either frequency hopping spread spectrum (FHSS) or direct sequence spread
spectrum (DSSS).
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•
802.11a - an extension to 802.11 that applies to wireless LANs and provides up to 54
Mb/s in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing
encoding scheme rather than FHSS or DSSS.
•
802.11b - an extension to 802.11 that applies to wireless LANS and provides 11 Mb/s
transmission (with a fallback to 5.5, 2 and 1 Mb/s) in the 2.4 GHz band. 802.11b uses
only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing
wireless functionality comparable to Ethernet.
•
802.11g - applies to wireless LANs and provides 20+ Mb/s in the 2.4 GHz band.
The technology that is being adopted most widely today is 802.11b, and this will be further
explored below.
IEEE 802.11b (Wi-Fi)
The IEEE 802.11b specification allows for the wireless transmission of approximately 11
Mb/s of raw data at distances from several dozen to several hundred feet over the 2.4 GHz
unlicensed band. The distance depends on impediments, materials, and line of sight.
802.11b is an extension of Ethernet to wireless communication, and as such is quite liberal
about the kinds of data that pass over it. It's primarily used for TCP/IP, but can also handle
other forms of networking traffic, such as AppleTalk or PC filesharing standards.
Wi-Fi stands for wireless fidelity and is just another name for IEEE 802.11b. This is a term
used and advertised by the Wireless Ethernet Compatibility Alliance (WECA). "Wi-Fi" is used
in place of IEEE 802.11b in the same way that the term "Ethernet" is used in place of IEEE
802.3.
The industry group known as WECA certifies its members equipment as conforming to the
802.11b standard, and allows compliant hardware to be stamped Wi-Fi compatible, short for
Wireless Fidelity. The Wi-Fi seal of approval is an attempt at a guarantee of intercompatibility
between hundreds of vendors and thousands of devices. The reason IEEE does not have
such a mechanism, is that it only promulgates standards.
WECA’s mission is to certify interoperability of Wi-Fi products and to promote Wi-Fi as the
global wireless LAN standard across all market segments.
802.11b has become the only standard deployed to a great extent for public short-range
networks, such as those found at airports, hotels, conference centres, cafés and restaurants.
Several companies currently offer paid hourly, session-based, or unlimited monthly access
via their deployed networks around the USA and internationally.
IEEE 802.11b is an improvement of IEEE 802.11, as it can transmit data at speeds of up to
11 Mb/s as opposed to 2 Mb/s for IEEE 802.11. Yet this speed is only theoretical, as part of
the signal only gets transmitted at 1 Mb/s anyway. According to Network Computing [37],
because a 192-bit header payload is transmitted at 1 Mb/s, 802.11b is at best only 85
percent efficient at the physical layer.
The standard is backwards compatible with the earlier specification 802.11, allowing speeds
of 1, 2, 5.5 and 11 Mb/s on the same transmitters. If an 802.11b device is moving, the device
and access point adapts and uses a less complex and slower encoding mechanism to send
data.
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Several new, incompatible protocols are in the process of being released, including 802.11a
(54 Mb/s over the 5 GHz band) and 802.11g (22 Mb/s over 2.4 GHz). IEEE 802.11a is also
called Wi-Fi5, as it also is approved by WECA and operates in the 5GHz band.
4.6.2 The HiperLAN technologies
HiperLAN is a set of WLAN communication standards primarily used in European countries.
There are two specifications: HiperLAN 1 and HiperLAN 2. These are both developed by the
European Telecommunications Standards Institute (ETSI).
The HiperLAN standards provide features and capabilities similar to those of the IEEE
802.11 wireless local area network standards [14].
HiperLAN1 provides communications at up to 20 Mb/s in the 5-GHz range of the radio
frequency spectrum. HiperLAN 2 operates at up to 54 Mb/s in the same RF band. HiperLAN
2 is supposed to be compatible with 3G WWAN systems for sending and receiving data,
images, and voice communications. HiperLAN 2 has the potential, and is intended, for
implementation worldwide in conjunction with similar systems in the 5-GHz RF band.
4.6.3 Bluetooth
Bluetooth is the name of a short-range radio technology aimed at simplifying communications
among networking devices and between devices and the Internet. It also aims to simplify
data transfer between peripheral devices and computers. Bluetooth's founding members
include Ericsson, IBM, Intel, Nokia and Toshiba.
Bluetooth is a standard developed to allow any sort of electronic equipment, from computers
and cell phones to keyboards and headphones, to make its own connections, without wires,
cables or any direct action from a user. Bluetooth is intended to be a standard that works at
two levels, both at the physical level as a radio communication standard, and at higher
network layer levels as the protocol for connection setup and communication control.
From a user's point of view, there are three important features to Bluetooth:
•
•
•
It's wireless. There is no need to worry about keeping track of all the cables to attach
the various components, and you can design your office without wondering where all
the wires will go.
It's inexpensive. The technology is designed with manufacturing expenses in mind,
which should make it possible to make networking products, which use Bluetooth
cheaper than other wireless systems.
You don't have to think about it. Bluetooth doesn't require you to do anything special
to make it work. The devices find one another and strike up a conversation without
any user input at all.
The most serious drawback to the Bluetooth technology is that the low power limits the range
of two Bluetooth devices communicating with each other to about 10 meters.
Bluetooth is capable of both synchronous and asynchronous data transfer. If a particular use
calls for an asynchronous, Bluetooth can transmit up to 721 kb/s in one direction, with 57.6
kb/s in the other. If the use calls for the same speed in both directions, a link with 432.6-kb/s
capacity in each direction can be made. The channel actually has a capacity of 1Mb/s, but
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headers and handshaking information take up about 20 percent of the capacity. If several
devices (more than two) are interconnected, they set up a piconet, where the total transfer
capacity still is 1 Mb/s. Several piconets can coexist without interfering with each other
though, making it possible to have more than one Bluetooth connection in an area.
[38]
4.6.4 The WLAN standard muddle
The fact that WLAN technologies employ frequency bands that are not licensed, mean that
there are many of these technologies that use the same frequencies. This means that one
can in practice only use one technology at a time, introducing another could mean
considerable interference and therefore less effective networks.
In the 2.4 GHz band IEEE 802.11b leads current deployment, but the emerging technology of
Bluetooth will also be using this frequency. It is expected that when the amount of Bluetooth
equipment becomes significant, WLAN products will migrate to the 5 GHz band to avoid
interference created by Bluetooth. This could mean that current IEEE 802.11b networks will
be phased out, and that the 5 GHz technologies will take over as leading WLAN
technologies.
The 5 GHz band will be the frequencies used by IEEE 802.11a and the ETSI HiperLAN2.
There are discussions of a convergence of 802.11a and HiperLAN2 technologies, which
would be beneficial by providing a clear market focus in the 5 GHz band similar to what has
been accomplished in the 2.4 GHz band. This initiative was launched recently between IEEE
and ETSI, and thanks to the harmonization effort already made, this can be envisaged in
reasonable time.
4.6.5 Interworking WLANs and WWANs
Parallel to the expansion and upgrading of mobile phone networks and services, we see that
in the public environment operators are starting to offer wireless services in the form of
WLANs in selected hot spots, airports, hotels, and cafés. These services are data only and
oriented to nomadic use.
For both WLANs and WWANs, a constant objective is to evolve into higher throughput in a
mobile environment, similar to the performance users experience in the wirelined business
and home environments.
To reach such performance, new radio interfaces have to be envisaged, similar to current
WLAN technologies. WLAN does not belong to the evolution path of mobile phone networks
presented before, but started as a wireless extension to enterprise LAN networks. Confined
to a second tier role for a long time, it has recently affected a breakthrough from its original
application toward home and public space, appearing as a disruptive technology due to its
undisputed cost to performance ratio. Some are even seeing WLAN as a replacement for
mobile networks whereas it should be seen from its strong points more as a complement to
the widearea 3G networks, offering close interworking to ensure proper delivery of services
according to the most appropriate available access network.
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A future seamless network architecture
Three different network layers can be defined [30]:
•
•
•
A mobile cellular layer for full coverage, multimedia, medium-bit-rate applications.
This is the area of GSM, EDGE, or UMTS mobile networks.
A hot spot layer for high bit rates in a short-range local mobility environment. This is
the area of WLAN networks.
A personal network layer to provide a short range of interconnectivity between
different equipment like printers, PDAs, mobile phones or even home appliances.
Interconnection of this equipment to the other layers of communications via
multimode terminals is the area of Bluetooth.
The transparent delivery of services across these network layers in an optimum way will
require a dynamic bandwidth management function operating on diverse wireless
technologies while maintaining a continuous session. This new media access layer will
connect the access networks to the core network while ensuring mobility management,
security, and Quality of Service (QoS).
The ETSI Broadband Radio Access Network standardization body investigates two
approaches for interconnection of WLAN and UMTS networks in connection with HiperLAN 2
standardisation:
•
A tight coupling scheme, offering seamless handover and the same level of security
in WLAN and UMTS networks. This approach would require a simplified WWAN
interface to renter interconnection of WLAN network to UMTS core network possible.
•
A loose coupling scheme, which would rely on IP protocols to organize mobility and
roaming between access networks. Interworking between WLAN and the core
network is performed between the authentication, authorization, and accounting
server and the home location register on the mobile network. Mobile IP and the home
agent/foreign agent concept will extend mobility to any network while preserving
seamless operation.
In the longer term, another approach is considered with the application making its own
choices based on application and user requirements together with the capability of the
different networks [30]. This would require higher intelligence in the terminals to make best
use of the different applications available locally. At the price of this complexity, this vision
brought out by the Wireless Strategic Initiative (WSI) may become real, bridging all access
technologies from fixed to satellite and from person to person to customized broadcast.
Roaming
In a typical environment, two or more access points will provide signals to a single client. The
client is responsible for choosing the most appropriate access point based on the signal
strength, network utilization and other factors. When a station determines the existing signal
is poor, it begins scanning for another access point. This can be done by passively listening
or by actively probing each channel and waiting for a response.
Once information has been received, the station selects the most appropriate signal and
sends an association request to the new access point. If the new access point sends an
association response, the client has successfully roamed to a new access point (make, then
break behaviour).
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This kind of network behaviour is common within all widely used networks, and a big
challenge for the telecommunications industry is to provide opportunities for users to
experience the same behaviour across network systems, making roaming possible not only
within one network, but across all networks.
4.7 Network summary
2G mobile communications has brought about a revolution in ways of living. In Western
Europe the penetration rate has reached more than 70 percent in less than 10 years since
the commercial launch of GSM. The uptake of 2G technologies has been tremendous, even
though several systems exist that are not interoperable. And the revolution is not over, with
mobile Internet and 3G services being offered in coming years. 3G will bring some
convergence, but will not achieve the goal of a single global technology.
Through an evolution of technology, new services have been or will be offered to
subscribers. Data services have really taken off in the last couple of years with SMS and iMode. GPRS packet data services have recently been launched, providing higher data rates
and the always-on capability, and at the network level, IP is becoming more important. UMTS
and its evolutions will provide even higher data rates, and a more comfortable offering of
more demanding services. The evolution from 2G toward 3G will also lead to more
convergence through a reduction of the number of main 3G cellular technologies. In hot spot
environments, WLAN is bringing a complementary technology toward cellular. In the longer
term, possibilities of interworking WWAN with WLAN technology are envisioned.
Even all this will not be the end of the evolution of mobile communications as activities are
ongoing within the research community on topics beyond 3G, for instance a satellite
component of UMTS and a Mobile Broadband System (MBS) at 60 GHz.
4.8 Comparison elements
In order to have some criteria for comparison of the different network types, some properties
must be chosen for comparison. The ones chosen here are the ones seen as relevant both
for users and network providers.
•
•
•
•
•
Data throughput
Mobility characteristics
Equipment cost for end-users
Installation cost for network provider
Data transfer costs for end-user
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Chapter 5 – Media architectures
This section will present some media types, mainly video formats, as this is perhaps the most
challenging aspect of multimedia transfer.
5.1 Codecs and file formats
The term codec is an acronym that stands for compression/decompression. A codec is an
algorithm, or specialized computer program, that reduces the number of bytes consumed by
large media files and programs.
In order to minimize the amount of storage space required for a complicated file, such as a
video, compression is used. Compression works by eliminating redundancies in data.
Compression can be done for any kind of file, including text, programs, images, audio, video,
and virtual reality (VR). Compression can reduce the size of a file by a factor of 100 or more
in some cases. For example, a 15-megabyte video might be reduced to 150 kilobytes. The
uncompressed file would be far too large to download from the Web in a reasonable length of
time, but the compressed file could usually be downloaded in a few seconds. For viewing, a
decompression algorithm, which "undoes" the compression, would have to be used.
There are numerous standard codec schemes. Some are used mainly to minimize file
transfer time, and are employed on the Internet. Others are intended to maximize the data
that can be stored in a given amount of disk space, or on a CD-ROM.
Codecs can be implemented in software, hardware, or a combination of both. They are used
in many popular Internet products, including QuickTime, Windows Media Player and
Netmeeting.
A file format may also be called a file architecture, and defines how data is stored. Two
examples of this is Microsofts ASF-file format, and the more open AVI-file format. Both file
formats can act as containers for video coded with specific codecs, for instance MPEG4.
5.2 Media Formats
Media formats are the form and technology used to communicate information. Multimedia
presentations, for example, combine sound, pictures, and videos, all of which are different
types of media. In section 1.3.5, a simple introduction to the different classes of media was
presented, and the following sections dwell further on the more complex media types of
sound and video as certain media formats of these types are presented.
5.2.1 MPEG formats
The MPEG family of file formats includes some well-known file types with the following file
name extensions: .mpg, .mpeg, .mp3, .mpa and .mpe.
The Moving Picture Experts Group (MPEG) standards are an ever-evolving set of standards
for video and audio coding and compression, which are developed by the Moving Picture
Experts Group. The best known standards are MPEG1, MPEG2, MPEG Audio Layer 3
(MP3) and the new MPEG4. The following is a short description of each of these formats.
MPEG1: This standard was designed to allow coding of progressive video at a transmission
rate of about 1.5 Mb/s. This file format was originally designed specifically for Video-CD
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(VCD) and CD-i media. The most common implementations of the MPEG1 standard provide
a video resolution of 352x240 (NTSC) / 352x288 (PAL) at 30 (NTSC) / 25 (PAL) frames per
second (fps), although other resolutions and frame rates are possible. When using this
standard, the result is a video quality slightly below the quality of conventional VHS VCR
videos.
MPEG2: MPEG2 is an enhanced form of MPEG1; it even includes MPEG1 headers in the
data stream. Major improvements include prediction modes and increased precision. The
result is a higher quality video, though at the expense of additional encoding/decoding
power. Video encoded with MPEG2 commonly uses a higher resolution than MPEG1, but
this is not an absolute rule. DVD video, as well as Super Video-CD (SVCD) is coded with
MPEG2. The screen resolution of DVD is 720x480 (NTSC) / 720x576 (PAL), while SVCD
uses 480x480 (NTSC) / 480x576 (PAL) [39].
MPEG Audio Layer-3 (MP3): This standard has also evolved from early MPEG work. It is an
audio compression technology that is part of the MPEG1 and MPEG2 specifications. MP3
was developed in 1991 by the Fraunhofer Institute in Germany, and it uses perceptual audio
coding to compress near-CD-quality sound by a factor of 12, while providing almost the same
fidelity. Perceptual audio coding eliminates audio frequencies which is inaudible to the
human ear.
It is noteworthy that there exist quite a few audio coding schemes that are more efficient and
produces the same or better quality sound than MP3, but because of it’s great success in the
PC user base, it has become a de facto standard for storing music on computers.
MPEG4: MPEG4 is the result of another international effort involving hundreds of
researchers and engineers from all over the world in the Motion Picture Experts Group.
MPEG4, whose formal ISO/IEC designation is ISO/IEC 14496 was finalized in October 1998
and became an International Standard in the first months of 1999. The backward compatible
extensions under the title of MPEG4 Version 2 were frozen at the end of 1999, to acquire the
formal International Standard Status early in 2000. Some work, on extensions in specific
domains, is still in progress.
MPEG4 builds on the proven success of three fields:
•
•
•
Digital television;
Interactive graphics applications (synthetic content);
Interactive multimedia (World Wide Web, distribution of and access to content)
MPEG4 provides the standardized technological elements enabling the integration of the
production, distribution and content access paradigms of the three fields.
Microsoft created the first implementation of this standard in the United States in Windows
Media Technologies with the release of the Microsoft MPEG4 version 3 video codec. This
standard was developed for encoding multimedia content efficiently in a variety of bit rates,
including low Internet rates to rates that reproduce a full-frame, television-quality
presentation. The Microsoft MPEG4 video codec intrinsically supports streaming multimedia
by allowing multiple streams to exist in one encoded data stream. This standard also has an
advanced motion estimation algorithm, which allows for greater compression.
Other versions of MPEG4 has since been developed by other authors. Both QuickTime and
DivX support their own versions of MPEG4. The goal over time will be to make the different
MPEG4 versions interoperable so that any player can play clips authored by any other
vendor.
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5.2.2 RealPlayer
Media files with the file extensions .ra, .rm and .ram are known as RealPlayer files.
Realplayer content is media that has been created by the software that is developed by
RealNetworks. This software can stream live or pre-recorded audio or video to a client
computer, either to a RealPlayer client program or a Web browser with the RealPlayer plugin, by decompressing it dynamically so that it can be played back in real time.
Real Networks is one of the industry leaders in Internet audio and video streaming
technologies. Their competitors include primarily Apple Computer's QuickTime and
Microsoft's Windows Media formats.
Their core technologies Real Video and Real Audio form the basis of many content
distribution systems for the Internet. Unlike many other solutions, their streaming
technologies use UDP and RTP, and require a special streaming server. Their main
consumer end software product is RealPlayer (now known as RealOne Player), the front-end
to the aforementioned technologies.
Real Audio and Real Video download a .ram file to your computer, which gives directions on
how to retrieve the audio stream. RealPlayer then connects and retrieves the .rm (Real
media/video) or .ra (Real audio) file.
RealPlayer supports Synchronized Multimedia Integration Language (SMIL), which is a
language for delivery of multimedia presentations.
5.2.3 QuickTime
QuickTime is more than it is often believed to be. In addition to the common understanding
that it is a video file format using the file extensions .mov and .qt, it is also a programming
library and API in C and Java made by Apple. The QuickTime concept includes a browser
plug-in and file format for the display, playback, editing and creation of all kinds of
multimedia, e.g. audio, video, animation, graphics, 3D graphics and VR. It is probably Apple's
most important technology after the Mac OS.
Official versions are available for Mac and Windows only, but there are several free software
projects to offer support on Linux as well.
In May 1991, Apple announced the first version of QuickTime, available on Macintosh only. It
was not until the World Wide Web became more widely used, and particularly when in 1994,
Apple released a version for Windows, that QuickTime came into its own. The QuickTime
plug-in enabled web users to view content such as movies and sound that were starting to
become available. Despite heavy competition from RealOne Player and Windows Media
Player, QuickTime is very popular. Over 100 million copies of QuickTime 4 were
downloaded, and QuickTime 5 is on track to exceed that within its first year of release. A
large proportion of this popularity is attributable to the fact that QuickTime is by far the most
popular format for the delivery of movie trailers on the web. Trailers such as those for Star
Wars: Episode I and Lord of The Rings were primarily available in QuickTime .mov format,
and millions of people installed it in order to able to view these.
It should be pointed out that QuickTime File Format (.mov) is not a codec itself, but a format
for delivering a large number of other codecs. The format is based on the Macintosh
resource fork, and is represented by a tree-like structure. Data and metadata is stored
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atoms, which are just containers. Branch atoms contain several related leaf atoms, which
hold the data itself. The actual media data is stored in tracks, so, for example, a movie clip
may contain a video track, an audio track and perhaps several text tracks for subtitles/closed
captions.
This format is very flexible, and openly documented, meaning third parties such as the
QuickTime for Linux project can create software that reads and writes .mov files without the
need for QuickTime to be installed. The format also actually forms the basis for the MPEG 4
standard.
QuickTime supports a large number of video compressors or codecs, but the most important
codec for QuickTime is probably the Sorenson codecs. These are licensed exclusively to
Apple and is a large factor in many decisions to choose QuickTime over other platforms for
video. The Sorenson codec gives very good quality and relatively small file sizes, and is
probably the thing that Linux and other non- Windows or Mac users miss most through not
having official QuickTime. It is supposedly a great codec, and Apple guards it jealously, with
good reason. The full list of codecs supported for input and output in QuickTime, can be
found in appendix C. Developers can also create plug-ins to enable further formats, which
can be automatically loaded when a file requiring them is encountered.
This media format also supports SMIL, and Apple has announced that support for official
MPEG4 will come in the next version.
QuickTime is also scriptable, with its own language, QScript. This can be embedded with
QuickTime movies, enabling developers to create mini applications that run through the
QuickTime player. A movie can also hold an embedded skin track that can turn the
QuickTime player into an easily customisable GUI for an application.
5.2.4 Microsoft’s Window media files
The following file formats are standards for the Microsoft Windows operating sytems, but are
also possible to use with Windows Media Player for other operating systems, like Linux and
MacOS [40].
Audio Visual Interleave (.avi): Audio Video Interleave (AVI) is a special case of Resource
Interchange File Format (RIFF). AVI is also a format that has been defined by Microsoft. The
.avi file format is perhaps the most common format for audio and video data on computers,
and this file format is a good example of a de facto standard. Many different codecs can be
used to form an .avi-file.
Advanced Streaming Format (.asf): This file format stores both audio and video
information, and it is specifically designed to run on networks like the Internet. This file format
is a flexible and compressed format that can contain streaming audio and/or video, slide
shows, and synchronized events. When .asf files are used, content is delivered to the
application as streamed data, whether it is streamed from the Internet or not.
An Audio Video Interleave (.avi) file can be compressed and converted to an .asf file, the
result being that the file can begin playing over networks after only a few seconds. Files can
be unlimited in length and can run over Internet bandwidths.
Windows Media Audio (.wma): This file type uses the Windows Media Audio codec created
by Microsoft. The codec is designed to handle all types of audio content. Such files are very
resistant to signal degradation that is caused by loss of data. This loss-tolerance makes this
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file type useful with streaming content. In addition, when an improved encoding algorithm is
used, this codec processes audio quickly. According to Microsoft, this improved compression
algorithm also creates smaller audio files than those that are created with most other codecs
that compress the same content. The smaller file size means that content that is created by
using the Windows Media Audio codec can be downloaded faster. The quality may suffer as
a consequence of fast and efficient compression though. According to Microsoft “Windows
Media Audio sounds better, delivering the same quality as MP3 at half the size“. [40]
Windows Media file with Audio and/or Video (.wmv): You can use a .wmv file either to
download and play files or to stream content. The .wmv file format is similar to the Advanced
Streaming Format file format. See above in the section on the .asf file type for more
information about the properties of these files.
Audio for Windows (.wav): Microsoft Windows uses the Wave Form Audio (WAV) file
format to store sounds as waveforms.
5.2.5 DivX
DivX is a video codec, and originally started as an alternate version of the Microsoft MPEG4
version 3 video codec, but DivX has gradually evolved into its own format. It is not a
particularly standardised format, as it has origins from the Open Source environment, and is
regurlarly updated. Currently, DivX version 5 is the latest, with more versions are sure to
follow.
DivX movie files often employ an MP3 audio codec for sound, but other sound codecs can
also be used.
This video file format has become very popular over the last couple of years as it makes it
possible to compress the video data from a DVD disc holding up to 8 GB of data to the size
of a CD disc, which holds around 700 MB. Of course this means sacrificing picture and
sound quality, but the result is more than acceptable in many cases.
5.2.6 Other media formats
It is worth mentioning a few other examples of media formats.
One example of a more effective audio compression scheme for network delivery purposes
than the popular MP3 format is ZeroChain [41], which uses an algorithm to combine sound
source coding with network channel coding. This means that not only the sound data is taken
into consideration when encoding the media file, but also the network channel properties
influence the encoding. This makes the media format more robust, for instance by providing
packet loss recoverability and continuous bit rate scalability.
Mpeg.org claims that Advanced Audio Coding (AAC) is more efficient than MP3 and is the
state of the art in audio compression technology [42], [43]. AAC is one of the audio
compression formats defined by the MPEG2 standard. Ac cording to Nokia [44], tests have
shown that AAC produces the same audio quality as MP3 using only 70% of the data rate.
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5.3 Media content and interface languages
To describe the content and presentation of multimedia, a few languages exist that cater for
different segments of media presentation.
5.3.1 SGML
SGML is an abbreviation of Standard Generalized Markup Language, a system for
organizing and tagging elements of a document. SGML was developed and standardized by
the International Organization for Standards (ISO) in 1986. SGML itself does not specify any
particular formatting; rather, it specifies the rules for tagging elements. These tags can then
be interpreted to format elements in different ways.
SGML is used widely to manage large documents that are subject to frequent revisions and
need to be printed in different formats. Because it is a large and complex system, it is not yet
widely used on personal computers. However, the growth of Internet, and especially the
World Wide Web, is creating renewed interest in SGML because the World Wide Web uses
HTML, which is one way of defining and interpreting tags according to SGML rules. SGML
itself is not used for multimedia presentation purposes.
5.3.2 HTML
Short for HyperText Markup Language, the authoring language defined by the World Wide
Web Consortium (W3C) and used to create documents on the World Wide Web. HTML is
similar to SGML, although it is not a strict subset.
HTML defines the structure and layout of a Web document by using a variety of tags and
attributes. There are hundreds of tags used to format and layout the information in a Web
page. Tags are also used to specify hypertext links. These allow Web developers to direct
users to other Web pages with only a click of the mouse on either an image or word(s).
5.3.3 XML
Short for eXtensible Markup Language, a specification also developed by the W3C. XML is a
pared-down version of SGML, designed especially for Web documents. It allows designers to
create their own customized tags, enabling the definition, transmission, validation, and
interpretation of data between applications and between organizations.
5.3.4 WML
Short for Wireless Markup Language, an XML language used to specify content and user
interface for WAP devices; the WAP forum provides a DTD for WML. Almost every mobile
phone browser around the world supports WML. WML pages are requested and served in
the same way as HTML pages.
5.3.5 SMIL
Short for Synchronized Multimedia Integration Language, a new markup language being
developed by the W3C that would enable Web developers to divide multimedia content into
separate files and streams (audio, video, text, and images), send them to a user's computer
individually, and then have them displayed together as if they were a single multimedia
stream. The ability to separate out the static text and images should make the multimedia
content much smaller so that it doesn't take as long to travel over the Internet.
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SMIL is based on the eXtensible Markup Language (XML). Rather than defining the actual
formats used to represent multimedia data, it defines the commands that specify whether the
various multimedia components should be played together or in sequence.
5.4 Multimedia Messaging Service (MMS)
MMS is a new globally accepted standard that lets users of MMS supportive mobile phones
send and receive messages with formatted text, graphics, photo-graphic imagery and audio
and video clips. Video sequences, audio clips and high-quality images can be downloaded to
the phone from WAP sites, transferred to the phone via an attached accessory, such as a
digital camera, or received in an MMS message. MMS messages can be sent either to
another MMS-enabled mobile phone or to an e-mail address. Photos, sound and video clips
can also be stored in the phone for later use.
MMS supports standard image formats such as GIF and JPEG, video formats such as
MPEG4 and audio formats such as MP3 and MIDI. Multimedia messaging is dependent on
high transmission speeds, something GPRS and certainly the new high-speed 3G
technologies should provide. To support the MMS technology, existing GSM networks need
to be upgraded with an MMS-C (Multimedia Messaging Service Centre).
In chapter 14 an application for composing MMS messages is demonstrated.
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Chapter 6 – Streaming
The following section will try to explain and discuss the concept of streaming media and
some of the issues related to streaming technology, like buffering, compression and Quality
of Service.
6.1 Streaming
It is important to be able to separate what is considered real streaming from what can be
called near streaming or pseudo-streaming. In addition, media that has to be completely
downloaded before viewing is another category.
To view a video or listen to audio via the Internet, you can either download it, or stream
it. The difference is that streamed media will begin playing as soon as a small portion of the
entire file has been buffered to the player. A downloaded video must be downloaded in
entirety, and then played. Examples of streaming formats are Windows Media, and Real
Media. An example of download formats is AVI.
Streaming media can be produced either live, or be previously edited. If it is produced in a
streaming format, you will be able to view it streaming - whether its live or previously edited.
Streaming media enables real-time or on-demand access to audio, video, and multimedia
content via the Internet or an intranet. Streaming media is transmitted by a specialized and
dedicated media server application, and is processed and played back by a client player
application, as it is received, leaving behind no residual copy of the content on the receiving
device.
When media is being streamed, be it true streaming or pseudo-streaming, it is the use of
buffering that cause a little wait time before playback begins. With this technique there is no
need to wait for the audio and video files to fully download before starting to view them.
Some defining characteristics of “streaming media”
Streaming is an emerging technology. There are many diverse, and often quite confusing,
definitions floating around. This section deals with streaming media only, i.e., audio, fullmotion video, and multimedia content, as opposed to other applications of streaming
technology, such as the streaming of real-time stock quotes. For this purpose, three primary
characteristics combine to define streaming media, as explained below:
1. Streaming media technology enables real-time or on-demand access to audio, video, and
multimedia content via the Internet or an intranet. Streaming technology enables the near
real-time transmission of events recorded in video and/or audio, as they happen, sometimes
called “Live-Live,” and commonly known as “webcasting”.
Streaming technology also makes it possible to conveniently distribute pre-recorded/preedited media on-demand. In other words, media that is stored and published on the Web in
streaming formats can be made available for access at any time.
2. Streaming media is transmitted by a media server application, and is processed and
played back by a client player application, as it is received. A client application, known as
player, can start playing back streaming media as soon as enough data has been received,
without having to wait for the entire file to have arrived. As data is transferred, it is
temporarily stored in a buffer until enough data has accumulated to be properly assembled
into the next sequence of the media stream. When streaming technology was first available,
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the ability to begin playback before the entire file had been transferred was a distinct
advantage. Now, however, pseudo-streaming techniques, such as progressive download,
allow some other formats to begin to play before file download is completed. So, while the
ability to begin playback prior to completing file transfer is a characteristic of streaming, it is
not, in and of itself, a differentiating factor.
3. A streamed file is received, processed, and played simultaneously and immediately,
leaving behind no residual copy of the content on the receiving device. An important
advantage of streaming media (unlike either traditional or progressive download) technology
is the copyright protection it provides. No copy of the content is left on the receiving device.
Therefore, the recipient can neither alter nor redistribute the content in an unauthorized
manner. In addition, there is far less need for substantial storage and memory capabilities on
the client device, as data that has been played is thrown away instantly.
6.2 Pseudo-streaming
For many purposes, streaming as strictly defined as above is not necessary. Pseudostreaming is another way of fetching media in a way that can be compared to real streaming
in many senses. One benefit of this setup is that it is very easy to set up pseudo-streaming
servers; usually they are just ordinary HyperText Transfer Protocol (HTTP)-servers that are
capable of transmitting a steady flow of data using the HTTP-protocol. To the user who is
receiving the media, it is hard to tell the difference. If the player is enabled for this kind of
transmission, it can start playing the media after a short while of buffering, still downloading
the rest of the media file while playing back the media. Ideally, the transmission speed will be
higher that the bandwidth of the media file, or else the playback will catch up with the
download process, and the playback will suffer from pauses.
There are of course drawbacks with this simpler form of media transmission. As it uses the
HTTP-protocol, there is no way of negotiating quality versus network bandwidth. The user
should therefore be able to choose a media bandwidth that is lower than the network
capacity for the network type they will be using. Since it uses a reliable TCP-connection, no
lost packets are skipped, so the player will have to wait for delayed packets to arrive before
going on if there is a delay in packets received. This will have the positive effect of quality in
picture and sound being just as good as when it was encoded, but the quality of continuity
could suffer. To prevent interruptions, the video being streamed should be received at least
as fast as the video is being decoded and displayed.
6.3 Streaming media players
Streaming audio is likely one of the most widely known applications of streaming media
across the Web. In 1995, RealNetworks Inc. released their RealPlayer plug-in to facilitate
real-time or streaming audio via Web browsers. The company expanded to address real
video with their streaming media plug-ins. As of 2000, there were three leading streaming
media players: RealPlayer, from RealNetworks, had over 130 million users; Windows Media,
from Microsoft, over 100 million users; QuickTime, from Apple Computer, 50 million users.
For strictly streaming audio purposes, MP3 had 50 million users.
Nokia, the mobile handset supplier, will offer RealNetworks’ RealOne Player tool on its
EPOC-based communicators and smart phones. RealNetworks and Sony recently signed an
agreement whereby RealOne Player will be embedded on Sony’s Playstation2 game
consoles. Microsoft’s Windows Media Player is available for the Pocket PC and is expected
to be available on Microsoft’s X-Box gaming console. This and other similar announcements
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provide opportunities for rich streaming media content delivery to mobile phone and wireless
computing devices. The mobile Internet computing market allegedly has the potential to grow
to 1 billion users by 2005.
The media players are presented in more detail in chapter 3.
6.4 Streaming infrastructure
The Synchronized Multimedia Integration Language (SMIL) presented in section 5.3.5,
assists with assembling an integrated multimedia streaming presentation. SMIL is a markup
language for describing the temporal behavior, screen layout and associated hyperlinks of a
streaming media presentation.
The SMIL specification was fostered by the World Wide Web Consortium (W3C) and is
emerging as a technology for next-generation Web development. Streaming media servers
need to be configured to support SMIL. Currently, RealSystem Server and QuickTime
Streaming Server products support SMIL. In addition, a number of software tools that
facilitate creating layout templates to easily build customized SMIL presentations are starting
to emerge. These tools are similar in functionality to HTML editors and include the GriNS
authoring tools from Oratrix Development [45] and Fluition from Confluent Technologies [46].
6.5 Streaming software
Tools for authoring, editing and encoding streaming media are also available from
RealNetworks, Apple, Microsoft and other companies. RealNetworks’ RealSystem Server
software supports serving and delivering streaming content across the Web. Apple’s
QuickTime Streaming Server and Microsoft’s Windows Media Server are other alternatives
for delivering streaming audio and video across the Internet.
6.6 Buffering
Buffering is also known as caching, and in this context it is a technique used in streaming,
both in real streaming and in pseudo-streaming. In order to smooth out the fluctuations in the
rate the media data arrives in, a chunk of the media data is stored before playback begins.
When enough data has been received, playback starts form the stored chunk, while data
coming in is again stored. This means that the media is not played back instantly as it comes
in, resulting in a little delay. When playing pre-recorded media, this is not something that
matters for the user, but when playing live media, buffering means a little delay for the
streamed media.
The reason for using buffering is the unreliable nature of the Internet, where data may arrive
out of order, too late or not at all. With a reserve of data, the problems are lessened when
applications can dip into the buffer and use that until the data stream is running as it should
again. If the data stream stop too long though, the buffer will be used up, and the media
stream will pause, or at least glitch.
6.7 Compression
Data compression means storing data in a format that requires less space than usual. There
are two ways of doing this, non-lossy compression and lossy compression.
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The non-lossy compression method means that one can transform the compressed data
back into the non-compressed form and it will be exactly the same as before. Examples of
this method are ZIP and ARJ. Lossy compression technologies on the other hand attempt to
eliminate redundant or unnecessary information, which means that the original data cannot
be regained. Most video and audio compression technologies, such as MPEG, use a lossy
technique. Lossy techniques are much more efficient than non-lossy techniques.
6.8 Quality of Service
Often shortened to QoS, Quality of Service is a concept that is highly relevant to multimedia
delivered on networks.
This is a networking term that specifies a guaranteed throughput level. When a client sets up
a connection with a server, some kind of QoS parameters could be agreed, and the user
would have a guarantee that the connection would be at least as good as the agreed
parameters.
In the current Internet there really is no QoS levels, as it works on a best-effort basis.
Nevertheless, the have been developed QoS protocols that are being used in some
networks. The most common QoS protocols are ATM, DiffServ, IntServ/RSVP, and MPLS.
Many groups are researching QoS for Internet; one of them is the Internet2 consortium [47],
more specifically the “Internet2 QoS Working Group”, whose mission is “to support the
development and deployment of advanced network applications through the use of IP traffic
differentiation. Their main project is the Qbone, an effort to specify, deploy, and evaluate new
IP services in an interdomain testbed. [48]
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6.9 Multiple Bit Rate Encoding
Multiple Bit Rate Encoding (MBR) is a technique where several versions of a media file is
stored in the same file on a media server, each version with a different bit rate. This means
that clients only download a part of the media file, namely the version that suits the
connection speed. The alternative to MBR is custom bit rate encoded files, which really is the
simplest and most common way of doing things. Table 4 compares some aspects of MBR
files and custom bit rate files [49], [16].
Optimizes Frame Size
Single File for Multiple
Connection Speeds
Adjusts Stream for
Network Congestions
Advantages
Custom Bit rate Files
Multiple Bit Rate Files
YES
NO
NO
YES
NO
YES
Size of the window varies
according to connection speed
so that viewers with faster
connections can view the video
in a larger window, making the
experience more enjoyable.
Viewer receives the stream
appropriate for their connection
speed. Requires only one link on
the site.
The sound can also be encoded
with different qualities.
Disadvantages
There must be placed multiple
links on the site (one for each
file). Viewer must know and
select their connection speed.
Viewers with high connection
speeds will have to view video in
smaller frame size to
accommodate viewers watching
lower bit rate files.
The sound settings must be the
same for all bandwidth streams
to avoid soundtrack disruptions
as the stream is adapted to
variable conditions.
Table 5 - Custom bit rate encoding vs. MBR
RealOne Player and Windows Media support MBR files.
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Chapter 7 – Market issues
Despite decreasing profits for the major mobile phone manufacturers the last year, it must be
said that there should be a very good market for mobile devices and multimedia services for
these units.
The amount of research and development that is being done in this area points to a
substantial optimism about the possibilities, both in income and services, for the new mobile
devices. As ITU Secretary General Yoshio Utsumi optimistically says in [50]: “The huge sums
of money that operators were prepared to invest in obtaining licences show the degree of
confidence in the technology and the potential market demand. Now that the first systems
are being deployed and 3G services and applications are being offered to the public, demand
for wireless multimedia development is likely to be on a growth curve for the next 10 years.”
Yet there has been a slowdown in development in this market segment as in many other ITrelated segments, due to cash dry out after a bad time for the IT stock markets. In addition
there have been some standardisation delays concerning both network standards and
content standards.
This chapter will take up some of the issues related with the mobile multimedia market.
7.1 Hardware demands
Mobile devices are fast becoming common property. This means that for the device
manufacturers to continue their earnings, they have to constantly design new devices with
more and better features. Recently, more devices have appeared that are fusions of mobile
phones and PDAs, which are called Smartphones. In the future, these will no doubt become
more popular, and will probably get smaller and lighter, although they will have to
accommodate the unit size to the unit’s display size. The screen display of future handheld
devices will become more important as the services and content evolve from speech to
picture and video. Devices could end up as no more than touch sensitive displays with all
input done by touch-screen or speech commands. Integration will become important, to fit
networking, processing and multimedia capabilities into one single unit is no doubt the goal
for many device manufacturers.
Figure 31 shows the soon to be released Sony Ericsson P800, which looks to be an exciting
new addition to the handheld market. Featuring a mobile phone, PDA-like functions and a
digital camera, it will be interesting to see how it catches on.
Figure 31 - Sony Ericsson P800
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7.2 Network demands
The promise of new wireless services technologies has spread around a large array of
numbers concerning network data throughput. The numbers that count is from 9.6 kb/s to as
much as 2 Mb/s and beyond. The question still remains: “How much capacity is really
needed?”
The answer may not be as high as one might think. If the capabilities of new wireless
technologies such as GPRS and EDGE are compared to the capabilities of a typical 56K
dial-up modem, we find that most applications can be done with much less bandwidth than
the new technology hype indicates.
Most of us have used the Internet for some form of multimedia transfer, be it audio or video
streaming applications. Non-real-time streaming works well on modem connections. The
limiting factor is often how long people are willing to wait for that first chunk of the file to
come in.
Full streaming video is the big bit stealer of applications. Video on demand still proves to be
a challenge for most fixed/landline networks. True real-time video conferencing requires not
only bandwidth but also QoS, which is required to reserve the resources to make it all work.
QoS improvements are being implemented in packet networks; an example is IPv6.
Initial applications has been limited to non-real time, which means that with the first offerings,
wireless networks included such favorites as e-mail, messaging, file transfer and Web
surfing, along with features dependant on these such as e-commerce and chat. Some of
these applications were offered using simple SMS. The difference between this and the
newer services is that the new networks promise reduced latency and a more robust
connection. “Always on” connections and the ability to connect securely to private networks
make these new connections the first real glimpse at true mobile Internet.
Now, the question is, if users can do all of this in the existing, lower bandwidth, why would a
carrier want to implement new technology such as EDGE or UMTS? According to Mike
Walters [51] the answer is capacity. EDGE and UMTS will bring improvements in overall
capacity to the wireless networks.
We already know that multimedia applications for wireless devices are possible. Now the
service providers need to make these applications more robust and capable of supporting
more subscribers using new applications.
Simply put, as the market grows for data in the wireless networks, we have to squeeze more
out of the available spectrum.
7.3 Market demands
The same thing that has been the case of the computer revolution that has happened the last
20-30 years is also in a large degree happening in the field of wireless systems today. Many
different vendors, in the hope that consumers want to use it, are developing new
technologies. The technology itself has been the main market driving force. The reason for
this is that these are totally new markets that consumers have no real experience with.
Twenty years ago, one could not really see the need for home consumers to have as
powerful personal computers at home as was used in work places. Yet it seems, that
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because the products were made available and affordable to the public, they wanted to buy
them.
This is perhaps also the case with mobile computing. Some years ago, there was not much
talk about mobile computing; even the use of ordinary mobile phones was not common. But
as new technology made units smaller and more affordable, everyone seemed to want, and
even need a mobile phone. Now that mobile phones are commonplace and the sales of PDA
and similar products are rising, the industry is looking at making earnings not just from the
technology, but also on content for use on the technology. One of the main challenges for
providers and manufacturers of mobile devices and services will be to create the market for
these services.
A relevant question is “How important is the multimedia market for the mobile networks?“
The answer is simple, very important. It is not only the consumers who wish to be able to
view video and other media using their mobile handsets, in fact the wish for multimedia on
handsets may be even more expressed from service providers and equipment
manufacturers. “Mobile video services provide operators with opportunities to generate
airtime traffic, revenue and customer loyalty that they cannot afford to overlook”, says a
report by analysts Northstream [52].
Main challenges for mobile operators will be to define a suitable service roadmap and
evolution; to come up with acceptable pricing models both for the providers and consumers
and to focus on content and digital rights management. In addition terminal adaptation and
traffic dimensioning will be key issues for supporting applications with higher bandwidth
requirements.
The Northstream report says that there are currently at least three types of mobile video
services that are identified as important in the 2.5-3G systems arena: mobile video
messaging, video telephony and mobile video distribution. It also claims that users will react
differently to each type.
•
•
•
Mobile video messaging will catch on quickly because market studies show a strong
demand for multimedia messaging services (MMS), including video.
Mobile video telephony services will also increase speedily as they significantly
enhance personal communications. Once consumers experience rich telephony, they
will quickly become accustomed to it and their expectations will rise accordingly.
The future of mobile video distribution services is unclear. Although Internet
streaming companies can use mobile networks to provide mobility, localization and
personalization and charge end users for accessing video content, it is uncertain
whether people will accept pay-per-view schemes, because video files can be freely
downloaded from the Internet.
7.4 Video Services Today and Tomorrow
With the widespread introduction of GPRS, mobile video messaging services and
downloading small video files into mobile devices will be possible due to the increased data
rates and the non-real-time characteristics of these services. The more demanding mobile
video services will only be a reality with the introduction of UMTS or other true 3G
technologies.
Mobile-equipment vendors, such as Ericsson, Nokia, Siemens etc, are developing solutions
that will enable the delivery of rich content to mobile devices, including video. Both
messaging and telephony are also a high priority, as this is what the public expects as a
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minimum. The migration path comprises enhancements to the SMS and MMS systems,
which will enable mobile video messaging applications. Video telephony services need 3G
because it offers data rates equal of circuit-switched networks, and a data rate of 64 kb/s
both to and from the terminal, which is a minimum for acceptable video telephony quality,
according to Ericsson. Streaming video distribution services are best supported with 3G
although sending full-length films to a phone or handheld appliance will be a niche
application for a long time.
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Chapter 8 – Multimedia scenarios
To illustrate some benefits and usage areas for multimedia services and applications on
mobile clients, some possible scenarios for the use of this kind of technology will be
presented.
In addition to mobile units being used as multimedia clients, some of the scenarios could also
be thought of in the context of the mobile unit being able to send multimedia over the network
as well as receiving it. This will be further explained in the scenario examples.
The set of future applications for 3G mobile systems are far from completely defined. This is
partly because of a lack of accurate marketing input on the development of applications [53],
and also from uncertainty about the portable devices’ design and specifications. Both are
important aspects in determining customer acceptance and the level of subscriber base for
the new systems.
8.1 Scenario classes
Scenarios can be grouped to make classes of scenarios that fundamentally do the same
thing, although in different contexts.
The classes defined here are the following:
•
•
•
•
•
•
•
•
Video Conferences
Instruction
Surveillance
Entertainment
Advertising
Information services
Location oriented services
Data transfer
8.1.1 Video Conferences
A very much publicized scenario for wireless multimedia is the
ability to carry out video conferences. This would mean that the
wireless device in question would have to have a camera and good
video processing abilities, as well as a good network connection in
order to get the quality that is needed. Figure 32 shows a prototype
mobile phone from Alcatel/Mitsubishi where video conferencing is
tried out. The following paragraphs describe possible scenarios
using video conferencing.
Remote surveying
An example of this is that an employee at the road administration
near to a site of interest, for instance a bridge or tunnel, can travel a
short distance to examine something, while a more experienced
expert can be of assistance or recieve needed information, both
video of the site and speech input from the actual surveyor through
the video conference.
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Figure 32 - Video
conferencing on
mobile phone
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Business and pleasure
Video conferencing is a well-known scenario, which is not really more than a complicated
phone call, where a video picture of the parties in question is also transferred. There seems
to be a wish for this kind of technology both in business life and also in social life, although in
social terms the technology would be called video telephoning rather than video
conferencing.
8.1.2 Instruction
Tele-education
Due to the lack of specialists and professionals in certain professions and areas, it could be
very useful to have the possibility of transmitting a lecture via the Internet or some other
network to interested parties. Normally this would probably be transmitted in a broadcasting
form to a larger audience, perhaps on stationary computers. But one could also imagine
users getting the transmission on a portable computer or on a PDA.
Remote instruction
In certain cases it could be useful to have a database of video clips or other media with
instructions on how to perform a certain task. This could be relevant in emergency situations,
or in other busy situations where the top expertise cannot be called upon very easily or if this
expertise would be too costly.
8.1.3 Surveillance
Alarm central / Mobile video surveillance
There are two main points to this scenario class.
One is that a person on a guard duty can have
control of several cameras with a portable device
as he is walking his watch round. Another is the
possibility for the guard to have a camera on his
device so that he can transmit what he sees to a
central.
Figure 33 shows an example of a surveillance
camera concept from Mobile Media, using their
image streaming technique over a low bit rate
network. A user having a PDA with a GPRS or
HSCSD network connection to a camera or
server controlling multiple cameras can follow
what is happening while in a mobile situation.
Figure 33 - Surveillance example from
Mobile Media's IceStream
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8.1.4 Entertainment
Broadcasting of entertainment
This scenario is highly relevant and will probably appear on mobile terminals as soon as the
providers can manage.
It most probably will not feature length movies, because as Robert Tercek, president of
PacketVideo’s applications and services unit, says in [54] “You should not expect multimedia
on mobile phones to be like TV – you won’t see half-hour TV programs on the phone. It’ll be
very much about quick hits, with video running 15-30 seconds, a minute tops.” But devices
like PDAs are more likely to be used for prolonged viewing, as the screen is quite large.
Games
The game industry will undoubtedly also welcome the new mobile multimedia options with
open arms. There is a big market potential in mobile gaming, as is shown by the big sales of
portable gaming devices, added to the fact that when new technologies in this industry is
presented, there has always been a game used on the technology to show the capabilities.
As was shown with the Siemens SL45i mobile phone in section 2.4.9, it is possible to
download games to some mobile phones today, but this market will grow as more phones
takes up this kind of technology.
8.1.5 Advertising
This concept is already beginning to become more and more a part of the day-to-day use of
the Internet as well as in use of mobile phones.
In the same way as television advertisements appear between television programs, video
advertisements have started to appear before and after video clips available on the internet.
This is especially the case when the sources of the video clips are web sites run by television
stations and newspapers. When media is sent to mobile device, some advertising could be
piggy-backed with the wanted media, perhaps to lower the cost for the end users.
Mobile users can experience this phenomenon particularly by SMS messages containing
advertisements or publicity information. Often these messages will be sent to the user by a
mobile service provider or other sources, to which a user has stated his or her phone
number. With the introduction of MMS and similar multimedia options, more advanced
advertising schemes are sure to follow.
8.1.6 Information Services
A multimedia terminal can be a good bearer of information, and a wireless multimedia
terminal can be a good bearer of information that one can carry around. Here there are
several scenarios that spring to mind.
Multimedia library
A library of multimedia clips or otherwise that can be accessed at will. This would be
something like browsing the Internet perhaps, only that the content would be centered on a
certain target group.
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Map services
There are already map services that exist for mobile devices, examples are map services for
WAP phones and map devices for cars. There could be a market for making these more
general and more informative, and this would probably be very suitable for use with PDAs.
E-news
This is also a well known application, with several possible ways of actually implementing it.
It could be a newscast, with users getting news on topics they have notified their interest for,
or the users could browse for news, a common practice on WWW and WAP. Finally one
could imagine news broadcasts like on TV sent to mobile devices if the networks could
handle it.
8.1.7 Location Oriented services
If the networks are able to work out the position of the mobile devices, some application
opportunities arise from this.
E-commerce
Shops could transmit an advertisement showing a sale to the user as he/she passes the
shop, a restaurant could send the menu, or a cinema could send an overview of current
films, with the possibility of buying tickets.
Travelling assistance and Tourist information
At airports, train stations and similar facilities it could be useful to get information about
locations and schedules directly to your mobile device. Also, users could be notified when
passing geographical places worth seeing. For instance, a user could be informed as he/she
is walking by a museum, and upon entering, a map of the building and information about the
displays could be downloaded to the user’s unit.
8.1.8 Data Transfer
With network speeds increasing, there will probably be a better market for data transfer
services on mobile clients.
8.2 Scenario summary
Most of the scenarios mentioned are available in some form on the Internet today, so there
are no revolutions in that sense. What these scenarios add to the existing services is the
ability to get these services or perform certain tasks whilst on the move.
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Chapter 9 – The state-of-the-art in today’s situation
In this chapter, an outline the technologies on the market that are most advanced and the
ones that are making the basis for the next generation of available technology will be made.
Wireless networks
The two network technologies that are most popular at the moment are GSM and IEEE
802.11b. One can clearly see that these are not the best technologies available, as markets
do not always go for the best technology, but perhaps for the one that is most available, most
affordable or most advertised.
IEEE 802.11a cards and access points are readily available, and not much more expensive
than the slower IEEE 802.11b technology, and with the possible frequency clash between
IEEE 802.11b and Bluetooth, there could be reason to think that the popularity of IEEE
802.11a could rise. At the moment IEEE 802.11a is the fastest standardised WLAN
technology available.
In the WWAN segment, the fastest and most advanced network currently available is GPRS,
but since this technology really does not outpace GSM with its HSCSD technology by much,
it is probably only the packet-based always-on part of this technology that makes it
something special. This feature is very important though, and really makes GPRS a breakthrough technology despite its limited transfer rate.
Mobile phones
For mobile phones, it is perhaps the forthcoming smartphones and communicators that can
be said to be the outstanding devices, especially ones with Java support. They offer far
better displays than “regular” mobile phones and in most cases have the possibility of
expanding their application range with downloadable applications.
PDAs
In the PDA class, Pocket PC PDAs are certainly leading the pack, both in processing power
and multimedia capabilities. Although Palm is working to close the gap, the Pocket PCs will
undoubtedly evolve as well.
Media technology
It is highly debatable which media format is “the best”. The answer is perhaps “some of
them”. As it stands, there are three main Internet media formats, Windows media, Real
media and QuickTime media. To say that one of these three is better than the others would
not be right, as they all have aspects that stand out to the alternatives.
MPEG4 has been introduced to the public in the last years, and work is still in progress on its
standardisation. This media format is certainly marked as the format for mobile multimedia
purposes.
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Chapter 10 – Related work
This chapter presents a few related surveys, to show some of the other work that has been
done in the field of mobile multimedia.
•
Multimedia standardization for 3G systems [55] by P. Haavisto, R. Castagno, and
H. Honko.
This article concentrates on the standards being made by ITU, 3GPP and others, and
discusses both the standards and the bodies that make these standards.
•
Processors for mobile applications [56] by F. Koushanfar, V. Prabhu, M. Potkonjak
and J.M. Rabaey.
This is an article that surveys embedded mobile processors, in the context of mobile devices
like laptops, PDAs and mobile phones.
•
Recent advances in cellular wireless communications [57] by M. Zeng, A.
Annamalai, and V.K. Bhargava.
This is a survey of mobile network standards, both 2G and 3G and goes into quite specific
details about the different networks.
•
A survey on the diffusion of existing media and the attitude towards new
multimedia services in Belgium [58] by A. Belpaire, T. Duhamel, H. Commandeur,
W. Verrycken, and N. Schillewaert.
This article is concerned with a survey on consumer’s views and wishes for new multimedia
service.
•
Standards for Multimedia Streaming and Communication over Wireless
Networks [59] by Dror Gill.
This is a document that describes possible standards for use in wireless media streaming
and communication applications.
•
Mobile Broadband Services: Classification, Characterization and Deployment
Scenarios [53] by Fernando J. Velez and Luis M. Correia.
This article is a classification for mobile broadband services, and goes into detail about
characteristics of different service classes
•
Mobile Multimedia – Challenges and opportunities by Stephan Hartwig [60] by
Matthias Lück, Janne Aaltonen, Reza Serafat and Wolfgang Theimer.
This article talks about different factors concerned with mobile multimedia, but also about
other media distribution types.
72
•
PART II - PRESTUDY
Mobile Network Evolution: A Revolution on the Move [30] by Johan De Vriendt,
Philippe Lainé, Christophe Lerouge, and Xiaofeng Xu.
This is an article that discusses the development of the mobile network architecture from 2G
to 3G.
10.1 Comparison to this thesis
Compared to this thesis, it can be said that the mentioned works are much more narrow in
their focusing points, some going into very specific details on the covered subjects, others
more general but still within a certain area of mobile multimedia.
This thesis on the other hand takes a much wider view, trying to grasp as many aspect of the
mobile multimedia situation as possible. It is therefore more of a wide overview over the
whole domain than a narrower survey into a part of the domain.
73
PART III – MY CONTRIBUTION
Part III – My contribution
Part three starts with a presentation and discussion of the difficulties that wireless multimedia
are facing, and proposes some solutions to these problems.
Then follows the evaluation of multimedia technology, in the forms of mobile devices,
network systems and video player applications.
Finally in this part there is a short presentation of a MMS composing tool, used to better
explain the concept of MMS messages.
Index
Chapter 11 – Challenges................................................................................................77
11.1 Processing limitations ...........................................................................................77
11.2 Network limits .........................................................................................................77
11.2.1 Example: GPRS limitations ................................................................................ 78
11.2.2 Mobile networks as IP networks ........................................................................ 79
11.2.3 Network availability............................................................................................. 79
11.2.4 Network diversity ................................................................................................ 80
11.2.5 Lack of Quality of Service .................................................................................. 80
11.3 Economic climate ...................................................................................................80
11.4 What comes first, the new technology or the new services?..........................81
11.5 Mobile content – more important than the terms WLAN and UMTS .............81
11.5.1 A possible scenario ............................................................................................ 81
11.5.2 Delivery challenges ............................................................................................ 82
Chapter 12 – Solutions ...................................................................................................83
12.1 “Time and money” ..................................................................................................83
12.2 Improved client devices ........................................................................................83
12.3 More advanced networks .....................................................................................83
12.4 Interworking of networks.......................................................................................84
12.5 IPv6 ..........................................................................................................................84
Chapter 13 – Evaluation .................................................................................................85
13.1 Evaluation of device hardware ............................................................................85
13.1.1 Laptops ............................................................................................................... 86
13.1.2 PDAs ................................................................................................................... 87
13.1.3 Mobile phones .................................................................................................... 88
13.1.4 Summary and evaluation of mobile devices ...................................................... 90
13.2 Evaluation of network types .................................................................................91
13.2.1 UMTS.................................................................................................................. 92
13.2.2 EDGE.................................................................................................................. 92
13.2.3 GPRS.................................................................................................................. 93
13.2.4 GSM (with HSCSD)............................................................................................ 93
13.2.5 IEEE 802.11b ..................................................................................................... 94
13.2.6 IEEE 802.11a ..................................................................................................... 94
13.2.7 HiperLAN 2 ......................................................................................................... 94
13.2.8 Bluetooth ............................................................................................................ 95
13.2.9 Network summary and evaluation (WLANs + WPAN) ...................................... 95
13.2.10 Network summary and evaluation (WWANs) .................................................. 96
75
13.3 Evaluation of media technology ..........................................................................98
13.3.1 Windows media player ....................................................................................... 98
13.3.2 RealOne Player .................................................................................................. 99
13.3.3 PocketTV ............................................................................................................ 99
13.3.4 Pocket DivX...................................................................................................... 100
13.3.5 PVPlayer........................................................................................................... 101
13.3.6 IceStream ......................................................................................................... 101
13.3.7 Conditions for trials........................................................................................... 102
13.3.8 Summary of media playing applications .......................................................... 102
13.3.9 General evaluation of media playing on portable unit ..................................... 103
Chapter 14 – A glance at MMS .................................................................................. 105
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Chapter 11 – Challenges
This chapter addresses the challenges connected with multimedia transfer to mobile devices.
Both the transfer and the presentation aspects have their difficulties, as well as other
important factors that come into the equation, namely users and providers.
Firstly some of the more obvious technical difficulties will be presented, and then more
commercial and social challenges are discussed.
11.1 Processing limitations
Looking at contemporary technology, the common impression is that the smaller a computer
unit is, the less processing power it possesses. As mobile devices are getting smaller and
smaller, it is hard to imagine them getting more powerful processors. But of course there is a
limit for how small a hand held device can be if it is to be of any use, and when the average
unit comes down to this size, the power of the processors will begin to increase more than
they are now. This is in line with the evolution of for instance laptop computers.
The amount of processing power needed for the display of fluent video of a reasonable size
is not insignificant. And the more compressed the video, the more power it takes to
decompress and display it. Therefore it is important that units with modest network
bandwidth have powerful processors, as the video transferred over low and medium rate
networks (such as GPRS and EDGE) will have to be considerably compressed.
Today, only Pocket PC devices using a 206 MHz processor can claim to have enough
processing power to handle most of the video formats available. As pointed out earlier in
chapter 2, the lesser handhelds like Palm devices and mobile phones have quite limited
processing capabilities, and acceptable quality video decoding will certainly be to difficult a
task for these devices.
Another issue here is the encoding of video, which would be relevant in scenarios with the
mobile device having a built-in camera, like the scenarios in sections 8.1.1 and 8.1.3. If the
processor were too weak, the device would only be able to send a small resolution and/or
slide show reminiscent video stream. This also clearly points to a need for more powerful
processors in such devices.
11.2 Network limits
A very important part of the notion of delivering multimedia services to wireless units is the
network capacity. As Tim Kridel says in [61]; “The first law of wireless data is that no
technology can ever hope to live up to its hype”. A good example of this is GPRS. It
promised so much when it was introduced with its theoretical data rate of 172 kb/s. When
users now experience real data transfer rates of about 30 kb/s with their new GPRS mobile
phones it must be said to be a bit of a disappointment.
Future networks will undoubtedly also suffer from practical limitations, bringing the actual
bandwidth down a bit from the theoretical maximum. There are always the problems of
possible weak signals and interference when using radio communication. When transferring
data, this leads to capacity-sapping overhead from resending lost or corrupted packets.
Another result is that data rate drops when changing from one coding method to another to
compensate for deteriorating conditions, in which more robust error detection and correction
77
algorithms come into play. An example of the limitations with a network system follows next,
and it is the newest commercially available network standard GPRS that gets criticised.
11.2.1 Example: GPRS limitations
It is clear that GPRS is a welcome addition to the existing mobile data services, as it offers
an improvement in spectrum efficiency, capability and functionality compared to earlier nonvoice mobile services. However, it must be stated that there are some limitations with GPRS.
Limited cell capacity for all users
GPRS does impact a network's existing cell capacity. There are limited radio resources that
can be deployed for different uses - use for one purpose precludes simultaneous use for
another. For example, voice and GPRS calls both use the same network resources. The
extent of the impact depends upon the number of timeslots, if any, that are reserved for
exclusive use of GPRS. However, GPRS does dynamically manage channel allocation and
allow a reduction in peak time signalling channel loading by sending short messages over
GPRS channels instead. Unlike HSCSD, the number of communication channels that have
been allocated for data transfer can and will change in the duration of the transfer, causing
network capacity to vary. The effect of this is that GPRS data throughput is quite variable,
and users can experience much lower data rates than expected.
Speeds much lower in reality
Achieving the theoretical maximum GPRS data transmission speed of 172.2 kb/s would
require a single user taking over all eight timeslots of a channel without any error protection.
Clearly, it is unlikely that a network operator will allow all timeslots to be used by a single
GPRS user. Additionally, the first GPRS terminals that have been released are somewhat
limited, supporting a maximum of four timeslots. According to Nokia, their GPRS mobiles will
support a 3+1 or 2+2 timeslot configuration [62], which corresponds to 3 slots for incoming
data and 1 slot for outgoing data, and 2 outgoing and 2 ingoing timeslots respectively.
The bandwidth available to a GPRS user will therefore be severely limited if compared to the
theoretical maximum bandwidth. As such, the theoretical maximum GPRS speeds should be
checked against the reality of constraints in the networks and terminals. The reality is that
mobile networks are always likely to have lower data transmission speeds than fixed
networks.
Data Rate
1 Timeslot
8 Timeslots
CS1
CS2
CS3
CS4
9.05 kb/s
13.4 kb/s
15.6 kb/s
21.4 kb/s
72.4 kb/s
107.2 kb/s
124.8 kb/s
171.2 kb/s
Table 6 - Data Rate for GPRS
Table 6 is the same table as Table 4, repeated here for the ease of the reader. If we assume
that CS2 with good error correction capabilities will be the most common coding of GPRS
data, we can see that 3 timeslots gives 3 x 13.4 kb/s = 40.2 kb/s, which is under a quarter of
the theoretical maximum transfer speed of GPRS.
The result is that relatively high mobile data speeds are not available to individual mobile
users until Enhanced Data rates for GSM Evolution (EDGE) or Universal Mobile Telephone
System (UMTS) are introduced.
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Suboptimal modulation
GPRS is based on a modulation technique known as Gaussian minimum-shift keying
(GMSK). EDGE is based on a new modulation scheme that allows a much higher bit rate
across the air interface- this is called eight-phase-shift keying (8 PSK) modulation. Since 8
PSK will also be used for 3G, network operators will need to incorporate it anyway at some
stage to make the transition to third generation mobile phone systems.
This means that GPRS certainly will be edged out by EDGE (or equivalent) in the future.
Transit delays
GPRS packets are sent in all different directions to reach the same destination. This opens
up the potential for one or some of those packets to be lost or corrupted during the data
transmission over the radio link. The GPRS standards recognize this inherent feature of
wireless packet technologies and incorporate data integrity and retransmission strategies.
However, the result is that potential transit delays can occur.
A negative characteristic of data transfer on mobile networks is the fact that roundtrip time for
a data packet is quite long. Roundtrip propagation delays have been reported to be up to
several hundred milliseconds, and according to Øystein Vik at Mobile Media they experience
delays in practice up to one second.
This means that when packets are lost and have to be retransmitted, there could be a long
pause in the data stream. The result is significant quality loss or even pause in the media
playback. Transfer protocols like HTTP use ordinary TCP/IP connections, and media
transferred with this protocol would suffer from this problem.
Because of this, applications requiring broadcast quality video may well instead be
implemented using High Speed Circuit Switched Data (HSCSD). HSCSD is as mentioned
earlier simply a Circuit Switched Data call in which a single user can take over up to four
separate channels at the same time. Because of its characteristic of end-to-end connection
between sender and recipient, transmission delays are less likely.
The result is that HSCSD could still be a needed technology, at least until networks with
much greater capacities are publicly available.
11.2.2 Mobile networks as IP networks
The transmission of IP packets on the mobile networks is not an ideal way of doing things.
When the mobile networks of today like GSM was designed, the intention was to carry voice
data and little else to end-users. Even with the introduction of GPRS the transmission of IP
packets does not go entirely smoothly.
11.2.3 Network availability
Getting the most out of the network when it is available is one thing, getting hold of the
network at all is another thing. When it comes to the new mobile phone networks, there are
constantly reports of delays on rollout for public use. The current status in Norway and much
of Europe, is that 3G network availability will come in the later stages of 2002.
Another angle on the availability issue is that of new network coverage. It is not certain that
all areas currently covered by GSM will get more advanced network coverage.
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Wireless networks specifically for data traffic in the form of WLANs are being installed in a
number of hotels, airports and other hot spots. As these kinds of networks only cost a few
thousand dollars to install even in large premises, for areas where it is natural for people to
use computers, 3G phone networks like UMTS will not be competitive in price.
11.2.4 Network diversity
Today there are many different standards available. Harmonization and convergence of
these standards means compromising, and compromising usually means a loss of
performance.
11.2.5 Lack of Quality of Service
The pure simplicity of the best-effort service model is one of the most important reasons for
the success of the Internet. It has allowed the IP protocol to be implemented over all kinds of
link-layer and has rendered extremely simple network management and inter-provider
peering possible. Together with the natural strengths of connectionless networking and the
end-to-end design principle, the best-effort service model has enabled a fast, dumb, cheap,
and hugely scalable Internet.
Quality of Service is a term used to described mechanisms that try to optimize the usage of a
network. They might include traffic shaping, priorities, services classes and such. In short,
network throughput is distributed and regulated using a given set of rules to guarantee a
higher quality of service.
In today’s Internet environment there really is no way of ensuring any Quality of Service. This
means that transfer of data could be slowed or even stopped if there is too much network
congestion.
In order for content providers of mobile multimedia to justify charging users for the services, it
is imperative that the services keep up a quality that is in line with the price of the service. If
QoS is not implemented properly, the services will seem flawed to the users, and this would
mean that it would be hard to justify billing of such services.
11.3 Economic climate
The last few years have not been as booming for the IT and telecom industry as was
expected in the mid-90s. This has meant that development of new technologies have slowed
down somewhat, a fact that also has been noticed in the mobile computing industry.
Both the development of new technology and services have been slower than previously
anticipated, because of more careful actors within the domain. One example of problems
related to the economy of mobile computing is the huge amount of money that was spent on
UMTS licences. For instance, British Telecom (BT) paid around £4 billion for a 20-year
UMTS license in the UK, and subsequently ended up in serious financial troubles. One of the
chief executives at BT at the time, Peter Bonfield, later said that they had probably paid twice
the amount they should have done. This is certainly not the only example of this sort, and it
goes to show that too optimistic visions a year or two ago, have now forced the business into
absolute wariness.
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11.4 What comes first, the new technology or the new services?
The answer to this question is of course the technology. But many equipment manufacturers
are reluctant to produce devices, having no available services. So even if the technology
exists, no product actually using the technology is made. And conversely, no services will be
made and provided if there are no devices that can make use of these services.
Since mobile multimedia is rather unknown territory commercially, no company wants to be
the first to place their bet, as the outcome is quite ambiguous. The massive commitment to
WAP on mobile phones cannot be said to have been anywhere near as successful as was
hoped, and now the new GPRS technology may suffer the same way.
If the usage of GPRS where it is available is anything to go by, new mobile technologies are
in for a hard time. In a report from Gartner Group, it is said that GPRS is not going to fulfil the
telecom business’ expectations for profits [63]. The reports claim that despite plenty of GPRS
phones being sold and the GPRS service being readily available, it is not being used. The
reason for this, they claim, is that neither the phones nor the service fulfils the customer’s
expectations of the new technology.
In contrast to this, in Japan, the i-Mode technology has been a tremendous success, and the
new 3G networks are tipped to improve this service further, increasing both the number of
users and the amount of profits being made.
The problem is that without proper content, the new technology and services will be
meaningless. No one needs a faster connection if there is nothing reasonable to connect to.
11.5 Mobile content – more important than the terms WLAN and
UMTS
Today’s debate about mobile content mainly focuses on which technologies that should be
delivering the content and how the income is to be divided between the content deliverer and
the network operator. This perspective only covers some of the future challenges.
One can visualize a future where most content can be delivered to a personalized mobile
service, where it will be natural to utilize different access technology and act with several
different specifications, according to what equipment is connected. Imagine a “connection
unit” that has a range of application that traditionally is covered by telephone, PDA, PC and
TV.
With such a service, perhaps manifested in some sort of connection card, one can imagine
delivery of mobile content where the quality varies according to the changes in the networks
and client technology. This kind of unit merges the terms of physical and logical mobility.
11.5.1 A possible scenario
The user is in the office with “the unit” connected to a LAN, and a large computer screen
available. His/her favourite team is about to play a World Cup football match, which is
starting before the user can go home from work. He/she starts to watch the game in a
window on the computer screen, delivered with TV quality on the LAN. Then, when it’s time
to go home, the user takes the connection unit and connects it to a PDA, where the game is
transferred to via a WLAN. On the way through the building, he/she gets good quality for the
PDA screen. As the user steps out to take the bus home, the network connection is handed
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over to a WWAN network, be it UMTS, EDGE, GPRS or GSM. Depending on what network is
available and what quality the user is willing to pay for, he/she can get either the best UMTS
rate, delivering both good quality picture and sound, a low EDGE rate, delivering reasonable
quality pictures or perhaps only a GSM rate, with just the sound commentary delivered to his
device. When the user finally comes home, he/she connects the unit to the home
entertainment system and can enjoy the game with full digital TV quality.
In this scenario it becomes obvious that the delivery of mobile content is something
completely different than content delivered on a mobile network. For the user that receives
the content, it is irrelevant if the delivery is made by wire or radio signals. It is also irrelevant
for the consumer if there is more than one network provider involved in the delivery. What is
not irrelevant, though, is what this kind of delivery would cost.
11.5.2 Delivery challenges
The consumer expects seamless delivery of content over heterogeneous networks. To
manage such a sequence of handovers, the industry will have to work with challenges on
technical, commercial and regulatory levels.
The technical challenges are quite obvious. A seamless integration of networks demands
that:
•
•
•
•
The units get unique addresses that are valid across all networks
Information about the connected unit and the networks’ capacity are mediated
between units, networks and content provider.
Security issues like authentication, encryption and handling of a single sign on must
be handled equally in the different wired and wireless networks.
Information that makes out the billing information for the service must be distributed to
the different actors of the content delivery.
In short, this scenario requires a considerable effort on standardisation issues for all actors
involved.
The commercial challenges are also very comprehensive. If a seamless integration like this
is realised, it demands that the following issues are resolved:
•
•
•
•
Agreements between the different parties that renders the content roaming possible,
perhaps even across national borders.
Mechanisms that ensure a correct account settlement for the end-user even with the
use of heterogeneous network during the delivery.
Price and contract structures that ensures that the income distribution between
content owner and content distributor is fair.
Assurance of content copyrights for the content owners.
Finally the question about regulatory issues comes up. If it looks like that the industry is
unable to ensure fair conditions for content providers, this may lead to regulation on content
provision. Regulations on resale of content, between content provider and network provider
and other such matters would have to be prepared and enforced, something that could lead
to long delays because of the bureaucracy involved.
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Chapter 12 – Solutions
In Chapter 11, a number of problems with today’s mobile computing situation were raised. In
this chapter, most of these problems will be addressed and some suggestions of solutions
will be discussed.
12.1 “Time and money”
Two key words are time and money, as is often the case with problems in the computing
field. Because the different factors are dependent on each other, technology development
and market needs are going to evolve in small steps. The network infrastructure will not be
expanded and upgraded as quickly as one could hope, as this costs a lot of money. As long
as there is a lack of both handsets and content for 3G mobile networks, the networks will not
be built quickly as there is not a large market for it. Conversely, consumers don’t want to buy
expensive new devices if the infrastructure does not allow optimal use of the devices.
An answer to this dilemma could be for the device manufacturers and content providers and
deliverers to create a market for these kinds of devices and services. Preparing a wide range
of services and quality content before offering the technology to the public could do this.
The experience with SMS messages was that even though it was available right from the
start of GSM in 1991, it was not until 2001 that this service got popular worldwide. In
Scandinavia users took an interest to SMS earlier, but it was not before 1998 the operators
felt there was a market for billing these messages. This goes to show that a big success like
SMS was not an instant success; it took a lot of time for it to become popular.
12.2 Improved client devices
As section 11.1 says, if there are to be introduced more complex services, the handsets for
mobile computing must generally become more powerful. Fortunately, there are no
indications that this is not going to happen. There are continually new devices being
presented with more powerful processors and more power efficient components, which show
that the development in this area by no means has stopped. Some examples follow: The
next generation of Pocket PCs will have processors running at double the speed of todays
models. The next generation of PalmOS devices will employ 32-bit processors instead of the
16-bit ones they have today. And finally mobile phones are likely to be given cut-down
versions of PDA processors, which really are much more powerful than those they have
today.
12.3 More advanced networks
The solution to the problems with network bandwidths from section 11.2 are really easily
solved, as there are new and more capable networks on the way already. EDGE and UMTS
promises to give data speeds of 384 kb/s to 2 Mb/s, and although neither are likely to fulfil
those promises completely, it is clear that data bit rates on mobile WWANs will increase.
Besides, the evolution of mobile networks does not end with 3G.
Section 11.2.2 also mentioned a problem of using IP on mobile networks. This may be a
problem on the 2,5G technologies like GPRS, as this is really just an overlay technology on
83
2G. But with true 3G mobile networks, where IP is an integral part of the architecture, even
mobile networks should finally become a quality media for IP transmission of data.
The problem raised in section 11.2.3, with possible lack of coverage by networks is not that
easy to solve, since the network providers will want to install their networks so as to make
the most profit. This means that some areas may never get UMTS for example. But then,
one may not need UMTS everywhere. Since areas without coverage of the most advanced
network system are most likely to be less populated, there will be much less demand on total
available bandwidth. So these areas may get the same bit rates from EDGE as more densely
populated areas would get from UMTS.
In section 11.2.4 the wide variety of networks is mentioned, and that harmonisation is
needed for interworking of these networks. There is no other solution for this than to do
exactly that, harmonise and converge. This means that networks will be more complex, but
hopefully also more flexible for new solutions.
12.4 Interworking of networks
By making different networks able to communicate better with one another, network
integration could be possible. This means that a user can continue a network session going
on one network type when he enters an area with another network type. This kind of
seamless handovers would mean that users could focus less on the technology and more on
the actual content or service delivered. That would in turn mean easier access to services,
something that most certainly would improve use and therefore profit for content providers
and deliverers.
12.5 IPv6
The new IP protocol, IPv6 will enhance mobility and QoS issues greatly as this new protocol
inherently contains parameters that are related to these issues.
The greatest challenge for Internet QoS is to implement lightweight traffic differentiation
schemes that improve use without adding considerable additional operational complexity or
endangering the principles that have made the Internet so successful.
In the context of multimedia delivery, QoS has a significant role. As audio and video data has
a temporal component, the data has to be delivered on time in order for the audio/video to be
played correctly. A QoS-quality in the network would be of great help when delivering such
media, as this could help to ensure that users got what they expected/paid for.
QoS for the Internet is a complicated work in progress designed to increase the ability of
real-time applications on the Internet. The Internet was designed as a "best-effort" network
that does not differentiate its service response between different traffic streams. The idea
behind QoS is to allow for different levels of bandwidth, delay variance (jitter) and so on.
These service levels will in effect augment the Internet to allow superior service levels, or
predictable service responses independent of network conditions. A widespread and end-toend QoS deployment would allow for applications to provide services such as video
conferencing, Internet phones, streaming media, multicasting and conferencing at different
rates for different service qualities.
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Chapter 13 – Evaluation
This part will describe how I evaluated mobile devices, media technology and network
systems, followed by the results of these evaluations. As in [7], we need some terms that can
be used to compare the different technologies. These terms will be the sets of evaluation
criteria that form the basis of comparison, firstly between the mobile devices and later
between the network types and media technologies.
First, there will be a presentation of the evaluation criteria used to evaluate mobile devices
with respect to several matters that are relevant to multimedia use. Thereafter, the actual
evaluation is done, with explanations and reasoning behind the evaluations.
The evaluations will consist of scores for each evaluation criteria on the following scale:
•
•
•
•
•
Very Good
Good
Fair
Poor
Very Poor
Similar sections concerning networks and media player technology are then presented. After
some criteria for evaluation is explained, the actual evaluation follows.
13.1 Evaluation of device hardware
Table 7 contains the criteria used to evaluate the device classes.
The reasoning behind the choice of criteria is that I have tried to pick out the elements that
have the most impact on multimedia capabilities, along with more general elements that have
to do with the public’s demands for handheld devices.
The importance of the criteria are not equal, and must be related to the setting in which the
portable device is going to be used. For instance, price (H5) and portability (H3) may be very
important to young users, while device capability (H9) and application capabilities (H2) may
be more important to corporate users. For the multimedia aspects, display (H1), device
capability (H9) and sound (H10) will be significant factors, while for mobility purposes,
portability (H3) and network connectivity (H4) are the most important criteria to consider.
In this evaluation some of the devices have not actually been tried out first hand,
nevertheless an evaluation is made as most criteria are sufficiently “measured” by reading
about them.
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H1
Display – Describes how good the display capabilities of the device are
in terms of display size, resolution, colour depth and general viewing
quality.
H2
Application capabilities – This criterion is meant to describe the variety
of multimedia application options available for a device.
H3
Portability – This describes how suited the device is for mobility in
terms of size, weight and mobile convenience.
H4
Network connectivity – Describes how the device is connected to a
network and tells something about the speed, ease of connectivity, how
accessible this network is and how versatile that network is.
H5
Price – This describes the cost of the device.
H6
Usage costs – This is meant to describe the cost of device usage in
terms of network use.
H7
Ease of use – This criterion describes how intuitive and user friendly a
device is in terms of multimedia use, for instance the user interface.
H8
Battery capability – This describes the longevity of the battery of the
device, which shows how long one can “stay mobile” in one go.
H9
Device capability – Describes some other capabilities of the device like
processing power (CPU), memory and storage.
H10
Sound capabilities – This is a criterion that describes the sound
capabilities of the device
Table 7 - Hardware evaluation criteria
13.1.1 Laptops
The display capabilities (H1) on laptop computers are excellent. One can have as large
screens as 15 inches, and resolutions up to at least 1600x1200 are getting common.
Application capabilities (H2) are also excellent, as virtually all applications can be run on this
kind of device. Portability (H3) is not very good compared to other mobile devices, even if
units are getting lighter and thinner, they still need to be of a certain size to contain a full
keyboard and a good display. In addition, accessories like extra batteries and battery
charging equipment also take up space.
As for network connectivity (H4), laptops are able to cope with all kinds of networks, from
WLANs down to GSM connections using a mobile phone or a GSM card. The connection will
nearly always be a TCP/IP connection to the Internet.
Laptop computers are clearly the most expensive units (H5) among the portable devices. A
run-of-the-mill laptop computer will cost about $1000 and upwards.
The usage costs (H6) for mobile computing depends on the type of network used and on
who provides the network connection. WLAN use can be free e.g. on school areas and in
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business buildings, or there can be a fee for connecting, e.g. in hotels and on airports. Mobile
connection using the mobile phone networks will have the same rate as other mobile phone
connections of this type.
The use (H7) of a laptop in multimedia terms is very easy. As the operating systems are fully
capable of showing most any content the media is “only a click away” and perhaps even not
that.
The battery (H8) is often one of the problems with laptops when mobility is an issue. This is
because of the rather great power consumption a laptop computer will have. A powerful
processor, a large screen and devices hard disks and CD-ROMs all add up to a considerable
power use. Therefore the battery on a laptop computer normally do not last more than 2-4
hours when in full use.
The general capabilities (H9) of the device are as one can read between the lines above very
good indeed. In fact many users have laptops as their main personal computer. It has good
display capabilities, can have powerful processors and large storage options, and can also
be expanded to some extent.
A laptop has the potential for very good sound (H10) options. State-of-the-art soundcards
and large speakers mean that laptops are able to produce as good sounds as any other PCs.
13.1.2 PDAs
The evaluation of PDA capabilities is going to be general, but there will be comments on
issues that divide the two main PDA classes, the Pocket PC units and the PalmOS units.
The display (H1) on a PDA takes up most of its front, which makes it a fairly good-sized
screen compared to the size of the whole unit. The resolution on Pocket PC units is 240x320
pixels, and on Palm devices it is 160x160. Virtually all Pocket PCs have colour displays, with
up to 65000 colours available. Palm devices are traditionally not as colourful, the older and
more reasonably priced models do not have colour screens at all using monochrome
displays, and even some of the newer models have only 4096 colours available.
In terms of multimedia applications (H2), Pocket PC units fare better than Palm units. Pocket
PC has the processing capability to display video clips as well as play audio, and even to
play some quite processor intensive games. Palm units have a far inferior processor, and
multimedia applications are therefore not as abundant, nor as advanced.
Portability (H3) of PDAs must be said to be very good. The average size of a PDA is about
the size of a hand, with Palm PDAs generally being a little smaller than their Pocket PC
counterparts. Adding network connectivity can pull down the portability impression, though.
The addition of a expansion jacket with network card to a Compaq iPAQ, about doubles its
weight, and also adds somewhat to its size. Bluetooth connectivity using Palm does on the
other hand not have to mean lessened portability, as its new Bluetooth connection card is
very small and inserted directly into the PDA.
The network connectivity (H4) features of PDAs very much depend on the infrastructure the
user has around him- or herself. Connection is possible with different types of network cards
or connection with mobile phones, resulting in networks ranging from GSM to IEEE 802.11b.
The price (H5) of a PDA also varies greatly, not at least between Palm and Pocket PC units.
Currently a Palm m515 (PalmOS) costs $399, and both the HP Journada 568 and the
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Compaq IPAQ H3835 (Pocket PCs) costs $599. The usage cost (H6) of wireless networks
for PDAs will be the same as for laptops.
For multimedia use (H7), the PDAs fare reasonably well comparable to laptops, but are
definitely in a class beneath them. Since both the input features are limited and screen space
for control interface for applications is sparse, it is less comfortable controlling the device. In
addition, the multimedia applications themselves are often poorer in many respects because
of memory and processing limits.
Battery capability (H8) of course varies between different models, but depending on how
much severe processing is done, the battery capacity on PowerPC devices can last up to 8
hours (HP Journada 690) before needing recharging. Palm devices on the other hand have
much longer battery life before recharging is needed, up to several weeks.
The processing power (H9) of PDAs have greatly increased with the emergence of the
Pocket PC family, but certain PDAs, especially the PalmOS PDAs are lacking in this
department. With current Pocket PC employing a 206 MHz processor, they can actually be
compared to desktop computers of 3-4 years back.
The sound (H10) options on PDAs vary a bit, with some of the Pocket PCs having good
sound processing capabilities and a reasonable speaker, while Palm units have until recently
not had proper sound output, just a speaker which could make beeping sounds and the like.
Pocket PC vs PalmOS
As one can see, there are quite some differences between devices using the two main
competitors of PDA operating systems. The display on current Pocket PC devices sport
better resolution than their Palm counterparts, although this may change with the next
version of PalmOS. Furthermore, the processing power of Pocket PC is quite a big way
ahead of Palm devices. This may mean that Pocket PCs are more power demanding, but as
they recharge quickly and most have enough battery to last a workday, this is in most cases
not really a very serious problem. The sound capabilities of a Palm device has until now not
been very impressive, but again, this is a area that may be evened out between the two OS’
in time.
13.1.3 Mobile phones
What is most striking are the limited display capabilities (H1) of mobile phones. Until recently
most models featured only a monochrome display, and screen resolutions were just around
90x60 pixels. The newer models have colour screens, but resolution is still very low. And as
the screens are bound to be small, mobile phones will probably never become popular as
units used for prolonged viewing.
A very limiting fact is that few mobile phones allow new applications (H2) to be installed on
the handsets. A new class of mobile phones are emerging, Java-enabled phones where new
applications are downloadable from the Internet or other sources. But the applications
themselves are not very advanced yet. One advanced application is WAP-browsers, and iMode phones are even more advanced, where display of moving video is possible. Some
handsets allow playback of MP3 music files stored on the unit.
Mobile phones are becoming very small and light, and their portability (H3) must be said to
be excellent. The networking options (H4) are limited to the mobile networks like GSM and
GPRS, which severely limit the available network bandwidth.
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The cost (H5) of purchasing a mobile phone varies a lot, a high-end mobile phone can cost
up to $500 depending on the network subscription offers, while a more commonly purchased
model but still with many of the important features like GPRS and Java-support may cost
around $300.
Network use (H6) with mobile phones can be costly, as the mobile networks charge users for
the usage. GPRS and other packet-based networks are probably less costly, as users are
only charged for the data actually transmitted.
The ease of multimedia use (H7) is not easy to evaluate for mobile phones, as there are few
phones that actually have any capabilities of this sort. User interfaces on mobile phones are
not very advanced, usually limited to a text menu system.
Battery capacities (H8) on mobile phones are generally very good, lasting perhaps a week
without recharging. But as with any portable unit, the more powerful the device, the more
power it drains from the battery.
Processing power (H9) on mobile phones has to be said is very poor. There is generally not
enough processing capability to decode neither video nor audio media.
As for sound (H10), mobile phones have not proved to have any good qualities in this area,
with an exception for a few select models with built-in MP3 players. It should be pointed out
though, that the MP3 playing part of such mobile phones is not strongly connected to the rest
of the phone, in terms of software and memory.
The newer Smart Phones and Communicators that are becoming available do feature other
and more advanced characteristics, and would come out better in evaluation like this.
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13.1.4 Summary and evaluation of mobile devices
Table 8 compares examples of actual values for the evaluation criteria. Table 9 explains the
terms used.
The division of the PDA class into a Pocket PC class and a PalmOS class is due to the
obvious capability differences in several of the properties.
Laptops
PDA
(Pocket PC)
PDA
(Palm OS)
Mobile Phones
R: 1024x728
C: 16 million
S: 15”
R: 240x320
C: 65000
S: 3.5”
R: 160x160
C: 65000
S: 3”
R: ~100x60
C: 2-256
S: 1.5”
Application
Numerous
Good range
Limited
Very limited
Portability
W: ~4000 grams
W: ~190 grams
W: ~140 grams
W: ~100 grams
WWANs
WLANs
WPANs
WWANs
WLANs
WPANs
WWANs
WLANs
WPANs
WWANs
WPANs
Price
~$2000
~$600
~$400
~$300
Usage cost
None – High
None – High
None – High
High
Ease of use
Excellent
Good
Good
Fair
Battery
2-3 hours
8-10 hours
1 week
1 week
P: 1800 MHz
M: 256 MB
S: 40 GB
P: 206 Mhz
M: 64 MB
S: <64 MB
P: 33 Mhz
M: 16 MB
S: <16 MB
P: Slow
M: Little
S: <Little
Full PC quality sound
Stereo sound
Very limited
Very Limited
Display
Network
Device
capabilities
Sound
Table 8 - Summary of mobile devices
Display
Portability
Device capabilities
R = resolution, C = colour depth, S = size in inches
W = weight
P = processor speed, M = memory, S = storage
Table 9 - Terms for Table 8
Note that memory and storage uses the same memory/storage space in PDAs and mobile
phones.
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Table 10 evaluates the different device classes according to the evaluation criteria.
Laptops
PDA
(Pocket PC)
PDA
(PalmOS)
Mobile Phones
Very Good
Good
Fair
Poor
Application
Very good
Fair
Good
Poor
Portability
Poor
Good
Good
Very Good
Network
Very Good
Good
Good
Poor
Price
Poor
Fair
Good
Very Good
Usage cost
Good
Good
Good
Fair
Ease of use
Very Good
Good
Good
Poor
Battery
Poor
Fair
Very Good
Very Good
Very Good
Good
Poor
Very Poor
Very Good
Good
Poor
Poor
Display
Device
capabilities
Sound
Table 10 - Evaluation of mobile devices
We see that laptops generally get high scores, and this reflects the versatility and power of
laptop computers. It scores low in two important mobile characteristics though, namely
Portability and Battery.
Pocket PC and PalmOS devices naturally, score quite similarly, but Pocket PC is better in
key areas for multimedia like Device capabilities, Display and Sound.
Mobile phones generally get low scores, this is because of less developed multimedia
characteristics. It does score very well in mobility areas though.
13.2 Evaluation of network types
To evaluate the different network types in terms of being suitable for multimedia, one could
be excused for thinking that capacity would be the only criteria worth investigating. But other
factors come into play as well, for this purpose mobility is very important, and cost is always
a relevant issue.
In this evaluation the network types in Table 11 will be evaluated:
WWANs:
• UMTS
• EDGE
• GPRS
• GSM
WLANs
• IEEE 802.11a
• IEEE 802.11b
• HiperLAN 2
WPAN
• Bluetooth
Table 11 - Network types to be evaluated
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As we can see, not all of these network types, like UMTS and HiperLAN 2, are available to
the public, and may even not be properly specified as yet, but they are taken into
consideration in the evaluation since they are highly relevant and the information available
about them is abundant.
Table 12 contains the criteria used to evaluate network types:
H1
Throughput – Describes the data rate available
H2
Mobility – Describes network range and network
coverage
H3
Unit price – Equipment cost for end-user
H4
Investment cost – Installation cost for network provider
H5
Usage cost – Usage cost of data transfer for end-user
Table 12 - Criteria for network evaluation
13.2.1 UMTS
The data rates of 3G networks are still very much discussed, and everything from 384 kb/s to
2 Mb/s is being touted as the maximum transfer speed (N1), depending on location and
device. The truth is probably somewhere in between. When fully operational, the theoretical
speed of UMTS will be 2 Mb/s, but this will be lower in practise because of limited total
capacity meaning that the more users, the lower the transfer rate for each user.
Mobility (N2) for UMTS users will be very good as it is a WWAN technology. And the ability to
roam over country borders and still have the same connection is very good. One problem
might be that UMTS may not be installed everywhere in the beginning, if at all. Urban areas
will be first, and it is unlikely that areas with low population will get UMTS, but insuch
locations a network type with a lesser capacity will probably do.
Prices (N3) for UMTS enabled handsets/cards are not available at the moment, but it is clear
that they will cost more than similar equipment of GSM/GPRS and EDGE type. This is
because they will probably include all these network systems, and be GSM/EDGE/UMTS
handsets.
The investment (N4) needed to cover the existing mobile-networked areas with UMTS are
enormous, and that probably the main reason for things taking time. Usage costs (N5) for the
UMTS network is also an unknown quantity, as the market does not know how to value the
services yet.
13.2.2 EDGE
EDGE is another technology that has not become available commercially, and therefore
some criteria will be difficult to evaluate. The maximum transfer speed (N1) is said to be 384
kb/s, but in practice this will probably be somewhat lower.
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Mobility (N2) of EDGE will be very good, as with other WWAN technologies. A point that
detracts from this is that EDGE may not be implemented in some areas if the network
evolution goes directly from GPRS to UMTS and there is not seen a need for EDGE.
EDGE clients will probably be more expensive (N3) than GPRS units, since they will
probably have both technologies available.
The cost (N4) for network providers to roll out EDGE networks is considerable, although
much of the technology upgrades needed for EDGE is also needed for UMTS, so since
EDGE is “on the way to UTMS” it is not likely that this would be the biggest problem. Pricing
of EDGE use (N5) is not as yet known.
13.2.3 GPRS
GPRS has not really lived up to its expectations on data throughput (N1), as there was talk of
150 kb/s ++ data rates a few years ago. The reality is that average speed on handsets will be
about 40 Kb/s, with bursts of up to 70 kb/s at occasions.
The mobility (N2) of a GPRS terminal/card is very good. They are small, so the personal
mobility is very good and because upgrading network stations from GSM to GPRS enabled is
not very expensive, location mobility is very good as well. Most areas with GSM will have
GPRS coverage in the near future.
At the moment GPRS units are priced (N3) about $100 above their GSM-only counterparts,
but this may not be only because of the GPRS feature. As the GPRS models also are the
newest models it is natural that the prices are somewhat higher. The Ericsson T65 is
probably one of the cheaper GPRS phones, costing about $250.
GPRS is favourable in the network investment department (N4), since the upgrading of the
GSM stations to GPRS stations are not very expensive. Since GPRS services are quite new,
the pricing of services (N5) are not settled yet and is quite diverse from service provider to
service provider and even from country to country. In Norway the price of 1 MB downloaded
data is about $3.
13.2.4 GSM (with HSCSD)
GSM is very limited in data throughput (N1) with only 9.6 kb/s as standard, but the GSM
HSCSD is clearly better with a theoretical top speed of 57.6 kb/s. The experienced
throughput will be more in the region of 40 kb/s though.
Coverage of GSM is excellent; it is the most used mobile network system in the world.
Mobility (N2) is therefore also excellent, although there are certain restrictions on roaming
across national borders.
GSM units are not expensive (N3) at all, with prices varying from $10 to $500. A reasonable
handset with most options should not cost more than $100.
As GSM already has been implemented practically all over the world, there will not be much
more network investment (N4) done with this technology. Usage costs (N5) are measured in
time spent connected and not in data volume transferred, which means that the cost
depends on the transfer speed as well as the volume. Cost for HSCSD use is commonly
twice as expensive as normal GSM data use. If we assume a constant transfer speed of 30
kb/s, 1 MB would take 267 seconds to download, which in Norway would cost about $3.
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13.2.5 IEEE 802.11b
The data throughput (N1) of this wireless network technology is stated as being 11 Mb/s at
maximum, with slower rates when conditions deteriorate. In reality the data rates usually are
more like 5.5 Mb/s.
Mobility (N2) is not IEEE 802.11b’s best quality. Although one can move around freely, its
range is quite limited. Officially it has a range of 100 meters, but under tests the signal quality
quickly deteriorates when moving away from the well-covered area, and 20 meters from the
building the signal was gone. In addition, there had been need to install many access points
in the building, a lot more than what the 100 meter range would suggest. Network coverage
is far from the levels of WWANs, but as the technology is popular there are many places with
IEEE 802.11b network access possibilities,
An IEEE 802.11b network card is not very expensive (N3), a D-Link DCF-650W card costs
$99, and installation of a WLAN (N4) in a site/building using this technology is regarded as
being good value for money. Companies and institutions can fairly simply install their own
WLAN using this technology.
As for usage costs for users (N5), there really is not any when the network is up and running,
except for the possibility of the network providers charging users for access to their network.
This could be the case in hotels and conference areas etc.
13.2.6 IEEE 802.11a
IEEE 802.11a has a maximum data rate (N1) of 54 Mb/s, but in practice the rate is around 30
Mb/s.
The mobility characteristic (N2) of range is the same as for IEEE 802.11b, but network
coverage is more limited as this technology is newer and less used.
Unit prices (N3) are about the same as for IEEE 802.11b. Network cards cost a little more
than IEEE 802.11b, but as sale volumes increase, the difference will probably disappear.
Investment costs (N4) are not higher than for 802.11b.
Usage cost (N5) is basically free.
13.2.7 HiperLAN 2
HiperLAN 2 is not a fully specified network technology, as it is still under development.
HiperLAN 2 promises maximum data rates (N1) of 54 Mb/s. Typical rate will be around 40
Mb/s.
As a WLAN, its range (N2) is limited. Sources claim the range will be 50 meters indoors and
300 meters outdoors. As a totally new technology it will initially have no network coverage
when released to the market.
Unit prices (N3) and investment costs (N4) are unknown, but will probably be somewhat
higher than other WLAN technologies.
Usage costs (N5) will be non-existent for corporate users, although hot-spot areas could offer
access services for temporary users for a small fee.
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13.2.8 Bluetooth
Bluetooth offers a data rate (N1) of around 1Mb/s theoretically, although real transfer rates
will be somewhat lower.
The mobility (N2) of Bluetooth technology is really not very good. The range is only five to ten
meters, which really makes the Bluetooth connected equipment stationary, although
wireless. The size and weight of Bluetooth connection cards are on the other hand very
portable, as they are very small and light.
Bluetooth cards for computer connectivity are allegedly going to become quite cheap (N3)
when the technology catches on commercially. At present, a Bluetooth from 3com costs
$104.
As Bluetooth is not a WLAN as such, there are very few cases where Bluetooth would be
used as a networking technology in the common sense. Therefore, the price (N4) for a
Bluetooth installation is not relevant in that respect. Bluetooth use does not cost (N5)
anything, and it is very doubtful that it ever will.
13.2.9 Network summary and evaluation (WLANs + WPAN)
The technologies are split into two groups, WLANs (including the WPAN) and WWANs. This
is because of rather big differences in usage and application at the moment.
Table 13 sums up some defining characteristics for the selected WLANs and WPAN.
Frequency band
Maximum data
rate
Typical carrier
rate
Typical range
(m)
Unit Price
Availability
Handover
support
Radio link
quality control
Bluetooth
IEEE 802.11b
IEEE 802.11a
ETSI HiperLAN 2
2.4 GHz
2.4 GHz
5 GHz
5GHz
1.5 Mb/s
11 Mb/s
54 Mb/s
54 Mb/s
< 1Mb/s
5.5 Mb/s
30 Mb/s
40 Mb/s
5-10
50-100
50-100
50 (indoor)/ 300
(outdoor)
~$100
~$100
~$150
?
Now
Now
Now
Late 2002
No
No
No
Yes
No
Yes
Yes
Yes
Table 13 – Summary of WLANs + WPAN
Table 14 shows the evaluation of WLANs and WPAN according to the chosen criteria. The
evaluation scale is the same as for hardware devices.
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Bluetooth
IEEE 802.11b
IEEE 802.11a
HiperLAN 2
Fair
Good
Very Good
Very Good
Mobility
Poor
Fair
Fair
Fair
Unit Price
Good
Good
Good
?
Investment cost
Very Good
Good
Fair
?
Usage cost
Very Good
Very Good
Very Good
Very Good
Data rate
Table 14 - Evaluation of WLANs + WPAN
Bluetooth is not suited for very mobile applications, but scores well otherwise. It really has its
own application area as a WPAN technology, and would work well in cooperation with a
WWAN or a WLAN.
IEEE 802.b and IEEE 802.a scores well and quite similarly, although IEEE 802.a has quite
an advantage with many times faster bit rate.
For HiperLAN 2 price issues are unknown, but otherwise the technology is promising.
13.2.10 Network summary and evaluation (WWANs)
Table 15 sums up characteristics of mobile networks.
Frequency band
Maximum data
rate
Typical rate
Availability
Network
availability
Unit Price
Investment
costs
Usage costs
GSM/HSCSD
GPRS
EDGE
UMTS
900/1800 MHz
900/1800 MHz
900/1800 Mhz
2000 MHz
9.6 – 57.6 kb/s
171.2 kb/s
384 kb/s
2 Mb/s
9.6~37 kb/s
40 kb/s
N/A
N/A
Now
Now
2003?
Late 2002 (?)
“Everywhere”
Dependant on
providers
Dependant on
providers
Urban only(?)
~$100
~$250
? (>GPRS)
? (>EDGE)
Low
Medium
High
Very High
High
High
?
?
Table 15 - Summary of mobile networks
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Table 16 evaluates the mobile networks (WWANs) according to the evaluation criteria.
GSM
GPRS
EDGE
UMTS
Poor
Poor
Fair
Good
Mobility
Very Good
Good
Fair
Fair
Unit Price
Very Good
Good
? (Poor)
? (Poor)
Investment cost
Very Good
Fair
Poor
Very Poor
Usage cost
Poor
Poor
? (Fair)
? (Fair)
Data rate
Table 16 - Evaluation of mobile networks
This evaluation also has some unknown factors. Cost of units and usage are completely
unknown as yet, and coverage of all networks except GSM is also quite uncertain. The most
uncertain elements are marked with question marks, but with tentative evaluations based on
expectations.
GSM as a technology is well rated, except for data rate. This is certainly an important criteria,
and the development of new technologies are because of GSMs shortcomings here.
GPRS really is not much of an improvement on GSM, when compared to other technologies.
EDGE will be an improvement bit rate-wise, but there still remains a question about how
widespread this technology will be.
UMTS is what everyone is looking forward to, and it certainly has promise, but investment
costs may lead to delays and poor network coverage initially.
As Table 16 shows, none of the mobile networks are rated as having good usage prices.
Certainly GSM and GPRS usage prices today are too high for those networks to be used
extensively, and although usage cost for EDGE and UMTS is as yet unknown, prices will
certainly be much higher than with WLAN use.
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13.3 Evaluation of media technology
This evaluation is somewhat limited, as it only applies for some selected applications in a
certain group of multimedia, namely video streaming/playback. The trials were done
somewhat informally, on a Compaq iPAQ 3850H PDA device with a D-Link DCF-650W IEEE
802.11b network card. The following applications was tried and tested under various
conditions:
•
•
•
•
•
•
Windows Media Player 8.0
RealOne Player (version 2.0.0.24)
PocketTV (version 0.6.8)
PVPlayer (version 2.0)
Pocket DivX (version 0.8)
IceStream
The media player applications tested to a serious extent were Windows Media Player 8,
RealOne Player, PocketTV and Pocket DivX. In addition, PVPlayer and a special version of
the IceStream player were tried.
The goals for the testing of these applications were to investigate what kind of quality one
can expect from a device like this and with different types of network environments. Playback
of media was done both with downloaded media resident in the device’s memory, and with
streaming media on the Internet.
There were not directly chosen any evaluation criteria for this evaluation, as this evaluation is
less dependent on numbers and known values.
13.3.1 Windows media player
This is the standard media playing application for the Pocket PC
2002 OS. It can only play back the Microsoft windows media file
formats wma, wmv and asf, in addition to MP3 files. Although
Microsoft claims that both the mms:// and http:// protocols can be
used to view the Microsoft media formats, I only managed to
view these files after downloading them locally, in other words it
did not accept pseudo-streaming of these files. Either the files
must be downloaded locally, or true streaming must occur. MP3
files must always be downloaded before playback.
Playback of video worked very well when playing locally, except
for playing files with too high bit rates. Probably because of
Figure 34 - Windows
processing capabilities limitations on the iPAQ, the video picture
Media Player
got glitchy when too demanding video files were played. When
playing files with bit rates up to about 200 kb/s everything looked and sounded good, but
when playing files of 256 kb/s and above the quality was less than impressive. Streaming
media files to Windows Media Player did not work in these tests either.
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13.3.2 RealOne Player
The RealOne Player application was special in the sense that
there is an option of setting the network type and bandwidth
the device is using. As I had the best network type available,
IEEE 802.11b with a bandwidth of 11 Mb/s, I could use the
other settings to “slow down” the network to see how
streaming would be using other network connectivity set-ups.
The available network types are 802.11b, HSCSD, GPRS,
CDPD, CSD (GSM) and CDMA. The bandwidth options were
in the range from 9.6 kb/s to 11 Mb/s, depending on the
selected network type. Of course, only the 802.11b network
type could offer network rates over 200 kb/s.
The playback of both local and streamed files worked very
well, although video files with high data rates became glitchy.
Again, This is probably an indication that the iPAQ was unable
Figure 35 - RealOne
to decode the high bit rate video data fast enough. There were
Player
signs of this at 256 kb/s, and at 512 kb/s it was very evident
that the application did not handle the data. At 200 kb/s the playback was fine.
This application featured many available options for network use and video presentation, and
had a very good full screen display, even at low bit rates. The use of the options to reduce
the network capacity made it possible to examine the streaming of media files on low
bandwidths. The result was quite good, as most of the real media files were encoded with
MBR. This lead to the player getting a media stream that was adapted for the available
network bandwidth.
13.3.3 PocketTV
This application was quite impressive. It can play back MPEG1
files very well both locally and from the net using pseudostreaming. It seemed to play high data rate files better than the
other MPEG1 capable player, but even so, at high bit rates the
video quality was reduced quite a bit. This is because of the
processing limitations on a handheld device. Nevertheless, the
application was very well made, and had a good full screen
mode.
Figure 36 - PocketTV
Figure 37 - Some screenshots from PocketTV
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13.3.4 Pocket DivX
Pocket DivX was stated to be able to play DivX video files,
MPEG1 files and MP3 audio both locally and pseudostreaming from the Internet. During my test I was unable to
stream any DivX files properly, only some still images was
displayed, even with a low bit rate DivX file. Streaming of
MPEG1 worked fine, though. When playing local files, the
DivX and MP3 files played very well, and high bit rate MPEG1
files was a bit glitchy. This application’s strongest points are
the capability of viewing several formats as well as good
quality playback. The weak points are that the player crashes
somewhat often, and that it can only play back DivX files
encoded with the oldest DivX codec, namely DivX 3.11. In
addition, the full screen mode seemed to be a bit flawed.
Figure 38 - Pocket DivX
Figure 39 - Screenshots from Pocket DivX
100
13.3.5 PVPlayer
Unfortunately I was unable to find very little media for the
PVPlayer application that would play. After many attempts on
the Packetvideo website, I finally managed to download one
MP4-file. This would more often than not only play the sound,
with no picture. As I have read favourable reviews of this
application my guess is that there are some software conflicts on
the iPAQ device I was using that lead to my failure. Yet, when it
worked it played the file rather smoothly, and the full screen
mode worked very well. Another disappointing fact is that it is
only willing to load files with an .MP4 file-extension, and thus will
not load any QuickTime files, contrary to what is claimed from
certain sources [54].
Figure 40 - PVPlayer
Figure 41 - Screenshot from
PVPlayer
13.3.6 IceStream
The version I tried was very special in that it only had one kind of
content, namely streaming of the Internet coverage of Big
Brother Norway. Nonetheless, it is the same technology that will
be used in a regular version of the application. Even though this
is a technology aimed at very low bit rate conditions, the image
quality is questionable, and has to be improved if it is to be
made commercially viable. As the transmissions were supposed
to be with bit rates of about 30 kb/s, which could be compared to
some of the media files played on RealOne Player and Windows
Media Player, they were quite disappointing in comparison to
these formats.
Figure 42 - IceStream
101
13.3.7 Conditions for trials
The network I had available for the tests was an
IEEE 802.11b WLAN installed on campus. This of
course offers much better data transfer rate than
would be experienced with mobile networks, but as
the RealOne Player had an option of limiting the
transfer speed and thereby emulate other network
types, I could use that application to get an
impression of how networks with lesser capacity
would function with video transmission. For
instance I could emulate GPRS with 1 to 8 slots, or
HSCSD with different speeds.
This emulation of lower bit rate networks was not
overly realistic, though, since there really was an
IEEE 802.11b connection behind the
GPRS/HSCSD connection. This meant that there
would be no lost packets, no packet roundtrip delay
and no sudden drop in connection data rate, which
are problems that are experienced with regular
mobile networks when used for real.
Except for Windows Media Player, which is bundled
with the Pocket PC OS as standard, all applications
were downloaded for free on the Internet. Content
used was also found on the internet, or provided to
me by a group of students writing a thesis on
“Storing, searching and delivering temporal data”.
The content for IceStream was really part of a pay
service, but as an academic user, Mobile Media
allowed me use of this application for free.
Figure 43 - The Compaq iPAQ
3850H PDA with D-Link DCF-650W
WLAN card
The equipment I had available for execution of any first hand testing was a Compaq iPAQ
3850H and an IEEE 802.11b network card, shown in figure 43. As this is a very versatile
device I felt that I could present a meaningful media player “test” after doing some trials with
some different applications.
13.3.8 Summary of media playing applications
The range of applications reflects the many media formats available. Although desktop and
laptop applications in many cases are able to play a wide array of formats, the cut down
handheld versions of the applications concentrate on one or a few formats. This is done so
as to keep down the size of the application and perhaps also to concentrate on doing as
good a job as possible on the media formats it supports.
RealOne Player is the only player capable of playing Realmedia, and it does so very well.
Windows Media Player also keeps largely to playing it’s own formats (plus MP3) and works
fine when playing local files, but streaming was unsuccessful in my attempts. If it in fact does
work, it is not an easy task to accomplish.
PocketTV was only capable of playing MPEG1 format files, and did so very well, both with
local and streamed files. Pocket DivX Player had an advantage in being able to play several
102
file formats, although PocketTV did the playback of MPEG1 files better. The ability to play
DivX files was unique though, and this worked very well.
Since PVPlayer did not work very well in my tests, and since IceStream both is based on a
totally different method of display and is in early stages of development, I feel that it is unfair
to compare them directly with the other players. PVPlayer uses a seemingly proprietary MP4
format, and content for this application was hard to find. IceStream seems to be more suited
to smaller displays like mobile phones than on PDA devices since PDAs have display
capabilities way beyond what IceStream is capable of showing.
To sum up, RealOne Player and Windows Media Player seems to be “must have”applications because of their ability to play the proprietary, but hugely popular formats for the
Internet, and PocketTV and Pocket DivX works well with MPEG1 and DivX, which can
become more popular as network bandwidths increase with new technology. Table 17 sums
up some important properties of the media player applications and the total impression given
by the applications.
Supported
formats
Streaming
capable
Full
Screen
mode
Framerate Proneness Impression
to glitch
of
and jitter
application
quality
Windows Media,
MP3
Yes(?)
Yes
Good
Minor
Good
Real media
Yes
Yes
Very Good
Minor
Very Good
PocketTV
MPEG1
Pseudostreaming
Yes
Good
Minor
Good
Pocket
DivX
MPEG1, DivX,
MP3
Pseudostreaming
Yes
Good
Some
Good
Proprietary
MP4,
QuickTime?
?
Yes
Fair
Some
Poor
Proprietary
streaming
format
Yes
No
Fair
None
Poor
Windows
Media
Player
RealOne
Player
PVPlayer
IceStream
Table 17 - Properties of Media players
13.3.9 General evaluation of media playing on portable unit
The impression given by the tests performed, strongly indicated that a device of the type
used, the Compaq iPAQ, is more than powerful enough for playback of good quality video
streams. Most media files that were played back were smooth and of good quality, except
those of bit rates higher than 250 kb/s. The trouble that was experienced with these video
streams is really not relevant, as that kind of high quality content is aimed at a larger display
than handheld devices are able to provide.
When playing video files of small bit rates, the quality suffered of course, but even with bit
rates as low as 27.0 kb/s, the picture was acceptably crisp and generally not too jittery to
watch. The sound was good even at this low rate, and high bit rate sound files like MP3
music files sounded as good as from any desktop PC.
103
Connection speed certainly did have an effect, as video played at 100 kb/s and above both
had fluent and well defined picture as well as good sound. With EDGE and UMTS this kind of
bit rate should be possible to achieve. But even GPRS/HSCSD bit rates were good enough
for enjoyable viewing of short video clips. For prolonged viewing, though, a better connection
and quality should be used.
The fact that several different media technologies worked so well also indicates a strong
device capability that also has a very general operation capability.
The display of a device like this is
quite suitable for mobile viewing of
video, an example of full screen
video is shown in Figure 44. The
display is large enough for enjoyable
viewing at 3,5 inches, whilst the
device in it self still manages to be
quite small and light. The quality of
the Compaq iPAQ display was also
good, although some darker media
clips were a bit hard to make out
under certain lighting conditions.
This is a characteristic that will differ
between various brands of PDA or
similar devices.
Figure 44 - Full screen video on PDA
The sound output quality on the PDA was also very good when using earphones instead of
the rather mediocre internal speaker on the device.
It should be noted that several of the video player applications had full screen display ability,
but as this used a screen mode that the screen capturing application was unable to handle,
all screen shots taken are of the media files being played in windowed mode. Windows
Media Player and RealOne player seemed to be using this video mode in windowed mode as
well, so no screen captures were made of video playback on these applications. Instead,
pictures taken with a camera show video playback on these applications.
More pictures of media playing can be found in appendix D.
104
Chapter 14 – A glance at MMS
In order to show how the “next big thing” in mobile phones is shaping up, the technology of
MMS messages are presented by showing how these kind of messages are built up.
Sony Ericsson has developed a MMS composer utility for PC use, which gives an idea of
how MMS messages are constructed. To get a better understanding of MMS and the buildup of these messages, this software is presented in short here.
The software itself is freely downloadable from Sony Ericsson’s web pages [64], and is
available for Microsoft Windows platforms only. The version tested here is not a full version,
as it could not transfer the MMS messages to a mobile phone.
The application GUI is shown in figures 45 to 47.
Figure 45 - MMS Compuser GUI
There is an area on the left, which is used to browse in media files like sounds, pictures and
animations. In addition it features a MMS player/emulator that plays the composed MMS
message.
On the right, a series of slides are shown to illustrate the different visual content used in a
message. Beneath these slides is a timeline, which the user can alter to set the timing of the
media components in the MMS message.
As is shown, the build-up of a message is a number of slides, which can contain a picture, a
sound or some text, or a combination of these three. The user sets the timing of the media
105
component, that is he/she indicates when the media component shall start to be
played/displayed and when it shall stop.
Figure 46 - MMS Composer GUI
Figure 47 - MMS Composer GUI
106
The media components used can be pictures like JPEG and GIF files, animations like GIF or
MPEG4 animations, sounds like WAV and MP3 files and finally text strings that are typed by
the user. This version did only accept WAV sound files and JPEG and GIF picture files.
Figure 48 shows the sequence of images and text that appear when the MMS message is
played. Of course, there is sound as well.
Figure 48 - A sequence of slides and animation
107
When the user is satisfied with his MMS message, he or she can transfer it to a mobile
phone with MMS capabilities, shown in figure 49.
Figure 49 - Exporting MMS message to a mobile phone
This application shows some of the capabilities of MMS, although it produces MMS
messages that are no doubt simpler than what commercial MMS service providers will be
able to produce. MMS messages that are composed on a MMS phone will probably be
similar to this in complexity.
108
PART IV – FUTURE VISIONS
Part IV – Future Visions
This part discusses the evolution in the mobile multimedia domain, and looks to point out
future directions for networks and devices.
Index
Chapter 15 - Future....................................................................................................... 111
15.1 How long will today’s technologies last? ......................................................... 111
15.1.1 Mobile networks ............................................................................................... 111
15.1.2 Other wireless networks................................................................................... 111
15.2 Hardware technology under development ...................................................... 112
15.2.1 Smartphones .................................................................................................... 112
15.2.2 Power consumption.......................................................................................... 112
15.2.3 Processing capability ....................................................................................... 112
15.2.4 Unit display....................................................................................................... 112
15.2.5 Miniaturisation .................................................................................................. 112
15.2.6 Technology integration ..................................................................................... 113
15.2.7 Operating systems ........................................................................................... 113
15.3 Network Technology in development .............................................................. 115
15.3.1 EDGE and UMTS ............................................................................................. 115
15.3.2 4G ..................................................................................................................... 115
15.3.3 HiperLAN .......................................................................................................... 116
15.4 Evolution of the service environment .............................................................. 116
15.5 Summary.............................................................................................................. 117
109
Chapter 15 - Future
This chapter introduces some of the developments in mobile multimedia. First the future for
current networks is discussed, and then the evolution of devices and networks are outlined.
Finally, a short summary of the future for mobile computing is made.
15.1 How long will today’s technologies last?
With current popular technologies in some cases over ten years old, like GSM, one would
think that with all the development being done in this domain, it would be time for the old
technologies to be phased out. This section discusses the future for the state of the art in
WWAN and WLAN segments.
15.1.1 Mobile networks
Today the most advanced technology in mobile phone networking that has been widely
implemented is GPRS (although the i-Mode technology is probably more advanced). The 3G
technologies have not been launched commercially, and reported delays mean that it could
still be a while before they are available to the general public.
The first step in the drive towards 3G would naturally be EDGE, but there seems to be a lack
of interest in expanding existing networks to EDGE capability in the hope that UMTS and
similar technologies will be ready for deployment in the near future.
The GSM network is the backbone of the whole GSM/GPRS/EDGE/UMTS evolution, and as
long as the user base for ordinary GSM is big, GSM will most probably not be phased out.
And with many users content with the simpler services provided by GSM, sales of GSM
handsets will probably be good for some time to come, especially if the price of more
advanced EGDE/UMTS handsets do not come down to the same level as GSM handsets.
15.1.2 Other wireless networks
The most widely used WLAN, IEEE 802.11b, has built itself a good foundation in the market,
but the emergence of Bluetooth in the same frequency band makes further investment in that
WLAN technology uncertain. Other WLAN technologies like IEEE 802.11a and HiperLAN
promises far superior transfer rates without the same frequency clash problems, as they
operate in another band entirely.
Vendors recommend investing in IEEE 802.11a instead of IEEE 802.11b, this is not only
because of increased capacity, but also so the vendors can start selling a whole new WLAN
infrastructure.
111
15.2 Hardware technology under development
In this section some issues concerning future mobile devices are discussed.
15.2.1 Smartphones
The first smartphones have already been introduced to the public, although only a few early
models have actually been released for sale. As the networks and services become more
suited to these kinds of handsets, and as the handsets themselves get more advanced, there
will probably be a greater market for these.
15.2.2 Power consumption
Power efficiency is an important matter for portable units, as being independent of any wired
connections is the main function of such devices. There are two kinds of improvement
possible here, components that drain less energy from the batteries and batteries that last
longer. As battery technology has been researched far longer than component efficiency, it is
likely that it is the latter technology that has the biggest potential for improvement.
15.2.3 Processing capability
As is natural, devices will get more powerful as components get “smarter” and faster. The
next generation of Pocket PCs will probably use a 400MHz Intel XScale Processor, and the
next PalmOS PDAs will move from the Motorola Dragonball processor to ARM processors
like the ones in use in current Pocket PC units, which also will mean more processing power.
According to ZDNet, Casio, Hitachi, Toshiba, Acer, HP and Fujitsu are all in the process of
making such models [66], which will feature both faster data processing and better battery
life. Intel says that the new processors are going to drain between 25 and 75 percent less
power than the previous processor, the Intel StrongARM SA-11110.
Other versions of the Intel Xscale processor running at 133, 200 and 300 MHz are also going
to be available, and will be put in use in less expensive PDA models, and perhaps even in
mobile phones.
15.2.4 Unit display
The displays on mobile devices has improved considerably the last couple of years, but with
the current PDA displays able to display over 65000 colours with a resolution of 240 x 320, it
is not too likely that there is any immediate need for improvement in this area. On mobile
phones there may be a tendency to increase display size, but this can be seen already on
Smartphones. Higher resolution displays could be an issue, but the 240 x 320 of Pocket PCs
and the upcoming 320 x 320 resolution of Palm OS devices should be enough for displays of
that size.
15.2.5 Miniaturisation
Devices are constantly getting smaller and lighter up to the point that is sensible. The main
miniaturisation issues will perhaps be the integration of more technology into a single unit,
rather than developing a smaller unit.
112
15.2.6 Technology integration
We are already seeing some mobile devices that have been released recently, where
network technology is embedded on the unit, instead of having to buy an external network
card. Perhaps units will come with more than one network option, making the scenario of a
multinetwork connection unit with seamless handover plausible.
15.2.7 Operating systems
According to reports, the Pocket PC OS will be released in new versions soon. One version
for smartphone devices, called Smartphone 2002, will take the Microsoft operating system
into the mobile phone segment of mobile devices. This version is planned to be released
later in 2002, and is aimed at voice-centric devices.
The other version, Pocket PC 2002 Phone Edition, is more data oriented, but will also have
voice features. This version is planned to be used in the upcoming Pocket PC PDAs.
For PalmOS PDAs the most exiting development at the moment must be the promised
PalmOS 5. This operating system promises to run 10 times faster than the version on current
Palm handhelds. In table Table 18 is an overview taken from ZDNet [70] of how the new
features in Palm OS 5 will stack up against its predecessor.
113
Features
PalmOS 4
PalmOS 5
Processor support
As a 16-bit OS, it supports the Motorola
68000 series chips. Currently, all Palm
devices are powered by a Dragonball
processor.
Will support ARM-based processors
from companies like Motorola, Intel, and
Texas Instruments. This means that
processing power of 32-bit OS 5
handhelds can run up to 10 times faster
than current devices.
In OS 4, you can only run one task or
program at a time. For example, when
you switch from Date Book to Memo
Pad, the OS closes one app and starts
the other.
OS 5 supports multithreading. This
means multiple tasks can be running at
the same time.
Software for older versions, if written
properly, will be able to run on OS 4
devices.
To protect investment in older software,
OS 5 supports the Application
Programming Interface (API) of OS 4.
So the new OS will be able to run
software that is fully compliant with OS
4.
Basic security available include locking
the device and hiding records. However,
there's no support for stronger 128-bit
encryption except through third-party
solutions.
OS 5 will have robust security options
and offer a system-wide 128-bit
encryption, including Secure Sockets
Layer (SSL) services for secure Internet
transactions, as a standard feature. A
new authorization and authentication
manager also allows various methods of
restricting access and identification via
biometric verfication (voice, fingerprints
or handwriting) and smart cards.
OS 4 has drivers and APIs that support
wireless connectivity via Bluetooth,
GSM, CDMA, and 2.5G/3G networks.
OS 5 extends the native support to
include 802.11b (Wi-Fi) wireless
networks.
Screen resolution of 160 x 160 pixels is
standard for OS 4. Sony, however, was
able to tweak the OS such that it
supports 320 x 320 pixels on the CLIEs.
User interface is consistant with
previous versions of the Palm OS.
High-resolution 320 x 320-pixel screens
are supported. Enhancements to fonts,
icons, graphics and other user interface
elements will be made to take
advantage of this feature. The OS is
also now "theme-able" and different
color themes are included.
Weak support for audio and video files.
Video and audio capabilities improved
with a new set of APIs that developers
can harness to deliver multimedia apps
and solutions.
No built-in Web browser. However,
third-party solutions are available.
PalmSource will provide a new,
standards-compliant browser for OS 5.
Program execution
Backward compatibility
Security
Wireless support
Graphics user interface (GUI)
Multimedia
Web browsing
Table 18 - PalmOS 4 vs. PalmOS 5
114
15.3 Network Technology in development
15.3.1 EDGE and UMTS
Although several 3G network systems are presented earlier in the report, their specifications
are far from finished, and implementations are still on the testing stadium.
The fact that there are several competing network standards being developed in parallel do
not ease the insecurity over what the next big network is going to be. If we concentrate on
the GSM-related technologies of EDGE and UMTS, it is planned that both network types will
be implemented and rolled out for public use. But since EDGE really is an inferior standard to
UMTS, there are concerns that EDGE never will be implemented in full scale. The hype
around UMTS have been enormous the last years, while EDGE has not really been in the
spotlight at all.
The fate of EDGE lies in the hands of the leading GSM operators, who may end up ignoring
EDGE and rather commit to UMTS, in which there have been made heavy investments
already, just for the licenses.
Also, the availability of handsets with the ability to use GPRS, EDGE and UMTS networks is
critical. Without this kind of triple terminals, a combined EDGE/UMTS 3G launch will be
meaningless.
If the handset manufacturers and network operators do not do an effort to “save” EDGE,
perhaps the technology of UMTS can do it, or rather the lack of UMTS technology. Some
sources like Bengt Nordström, president and CEO of Northstream AB, claim that there is a
possibility of rather serious launch delays for UMTS [67]. Signals of such delays are causing
uncertainty among GSM operators about when UMTS actually will be operational. If wireless
data is made popular with GPRS, there will be a considerable capacity and quality shortage
before UMTS can take over for GPRS. Upgrading GPRS with EDGE takes considerably less
investment, even less of an investment than deploying additional GPRS sites to increase
bandwidth.
This scenario is only applies if there is a considerable difference in the time between
availability of EDGE and UMTS, and at this time the official UMTS release schedule is still
the second half of 2002. As long as this is the case it is not likely that EDGE will become a
bridge between GPRS and UMTS.
15.3.2 4G
Already before 3G mobile networks are introduced to the public, there is considerable activity
concerning yet another generation of mobile networks, suitably named 4G [68]. The
enthusiasm for 4G is perhaps not so much because of accelerated progress in the science of
mobile networks, but more because of disappointment with the 3G standards. Instead of one
standard worldwide, there will be several that are not interoperable. The data speeds that will
actually be available will be considerably lower than early expectations pointed to. Therefore,
a Fourth-Generation Mobile Forum [69] has been set up, and companies will have invested
over $30 billion in 4G research and technology by 2003.
Unlike previous G’s, 4G will not be a product of the mobile phone industry alone, as several
actors in the wireless LAN domain are looking to be fused into the next generation of mobile
computing.
115
One of the most advanced projects is the Mobile Broadband System (MBS), with a prototype
system operating in the 60 GHz band, where there is much unused bandwidth, but as range
is limited to about 100 meters, a WWAN solution would require millions of base stations to
cover Europe. The prototype built in 1995 had a data rate of 34 Mb/s, although the target for
MBS was 155 Mb/s. Velez et al. also discusses MBS in [53].
With Japan being the only country where mobile multimedia data services have proved to be
profitable as yet, it is not surprising that there is development of new wireless technology
there either. NTT DoCoMO actually plans to have a 4G system operational by 2006.
Just the current packet-switching upgrade technology of GPRS is called 2,5G, improved
versions of 3G systems are often called 3,5G. The 3,5G upgrade closest to reality is called
High Speed Downlink Packet Access (HSDPA), which is set to be standardized during 2002.
This employs more efficient modulation techniques to reach up to 10 Mb/s.
15.3.3 HiperLAN
15.4 Evolution of the service environment
Elsen et al. has a very good figure in [30], which has been recreated here in figures 61 and
62. These indicate that the service environment for mobile service will shift from a vertically
integrated to a horizontally layered mobile service environment. The future networks will
seamlessly integrate Internet protocol transport with a variety of different access networks.
This means that the same
services should be accessible
to all sorts of terminals using
the same transport protocol, for
instance IPv6. The network
carrying the data will depend
on availability and subscription,
but all networks will be able to
carry the data/media to the
end-user’s terminal of choice.
Today
Services
Mobile
networks
PSTN/
ISDN
Cable
television
Data/IP
networks
|
Figure 50 - Today's service environment
116
Future
Services
Mobile
networks
PSTN/
ISDN
Data/IP
networks
Cable
television
Transport
|
Figure 51 - Service environment of future 3G network
15.5 Summary
Although current technologies probably have quite a bit of their lifetimes left, many new
technologies are being developed in order to take over and improve use of mobile
computing. Certainly, improvement of mobile computing infrastructure, in forms of networks
and protocols, will have a great effect on the possibilities for offering multimedia services for
mobile clients.
A movement towards harmonization and convergence of different data transport
technologies will in time probably also lead to a convergence of services, so that the same
services and transport networks can be used by all kinds of client hardware, from PCs to
mobile phones.
117
A survey of multimedia technologies on mobile devices PART V – SUMMARY & CONCLUSIONS
Part V – Summary & Conclusions
The main results of the survey and evaluation are identified in this part. The results are
outlined in a summary of the evaluation part, and with main basis in the prestudy part and the
evaluation part, a conclusion to the thesis is drawn.
Index
Chapter 16 – Summary ................................................................................................ 121
16.1 Summary of current situation............................................................................ 121
16.2 Summary of this thesis ...................................................................................... 121
Chapter 17 – Conclusion and further work............................................................ 122
17.1 Conclusion........................................................................................................... 122
17.2 Further work......................................................................................................... 122
119
Chapter 16 – Summary
16.1 Summary of current situation
At the present time, multimedia for mobile devices is certainly in a very early phase. There
are not many devices that can support advanced multimedia, and the coverage of networks
that have sufficient throughput is rather limited.
One question that is open to debate is how popular the next generation of mobile networks
will become. It not only depends on the quality of transmissions one would be able to
receive, another very important factor is the range of services and the quality of content that
is made available for public consumption. The cost for consumers, both in regards to
equipment cost and subscription and usage costs will also be a factor to be considered.
In chapter 13 evaluations of device hardware, wireless networks and media player
applications were made. The results point to an increasing maturity of mobile devices in the
laptop and PDA segment of devices, with mobile phones quite a way away from mobile
multimedia fitness yet.
The WWANs are not yet capable of proper multimedia transfer, but WLANs have more than
enough throughput to enjoy multimedia services whilst mobile. The trouble with WLANs is of
course limited mobility and network availability.
Media players available for portable devices was shown to be diverse and in most respects
well functioning.
16.2 Summary of this thesis
In this thesis I have looked into different technologies related to multimedia technologies for
mobile clients. The main focusing points have been portable devices, mobile/wireless
networks and media applications.
Evaluations of products in the different segments have been performed, and can be found in
chapter 13. In short, the results point to relative maturity in the device and application
segment, while the networks are as yet lagging behind in development and quality.
A drawback with this thesis is the fact that there were limited resources available for the
testing part. The evaluation was done only in part with actual hands-on testing, while most of
it was an evaluation using read material and theory.
Simulation of network technologies using available equipment and software increased the
applicability of the evaluation.
121
Chapter 17 – Conclusion and further work
17.1 Conclusion
With the introduction of powerful PDAs with impressive sound and video capabilities, the
industry have shown that the technical aspect of the client devices are in place for very
versatile and potentially very complex services. For a mobile device to have any use as a
multimedia tool it has to have a reasonable display, and PDAs are the smallest current
technology to have such a feature. The upcoming smartphones will perhaps come close in
ability, and eventually mobile phones and PDAs will probably merge into one class of
portable communication devices with multimedia capabilities.
The networking aspect of mobile multimedia has a considerable longer way to go before
reaching as high standards. Many of the current networks are not very capable in multimedia
terms, but the next generation (3G) of networks will hopefully deliver what it takes to provide
enjoyable use of mobile multimedia.
The most important factor in the success of mobile multimedia is not the technologies
involved, though. Without suitable and popular services for mobile clients, the technology
would be rendered virtually unused by a demanding public.
17.2 Further work
As the 3G networks finally get released into public use, it would be interesting to investigate
the true performance of such networks. Also, a further study of services and scenarios would
be useful.
Perhaps the most interesting and challenging problem that has been discussed in this thesis
is the integration of different network types and the possibility of seamless transfer of access
across these networks. This problem is highly relevant to the MOWAHS project.
122
PART VI – APPENDICES
Part VI – Appendices
This part contains the appendices for this thesis.
Index
Appendix A – References .........................................................................................A-1
Appendix B – Glossary..............................................................................................B-1
Appendix C - Technical information..........................................................................C-1
Appendix D – Pictures...............................................................................................D-1
123
Appendix A - References
[1]
MOWAHS. Web: http://www.mowahs.com
[2]
CAGIS. Web: http://www.idi.ntnu.no/~cagis/
[3]
Nua. Web: http://www.nua.com/surveys/
[4]
IDC. Web: http://www.idc.com/
[5]
Carl-Fredrik Sørensen. Issues for Development of Mobile Multimedia Systems.
NTNU – Dept. of Computer and Information Science, 2001
[6]
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A-5
Appendix B - Glossary
1G
First generation mobile telecommunication systems.
Analogue systems developed solely for speech. Very few still remain.
1XRTT
An implementation of CDMA.
2G
Second generation mobile telecommunication systems.
Digital systems capable of speech/data transfer
3G
Third generation mobile telecommunication systems.
Not yet fully specified or implemented.
3GPP
Third Generation Partnership Project
Organ that formulates technical specifications for 3G mobile systems
3GPP 2
Third Generation Partnership Project 2
Yet another organ that formulates technical specifications for 3G mobile
systems. Lead by American National Standards Institutes (ANSI) to
promote intersystem operations.
AAC
Adaptive Audio Coding
MPEG2 AAC is a new audio coding standard used in digital TV
broadcasting.
AC3
Dolby Digital 5.1.
AC3 is a method of encoding sound to five discrete or separate channels.
ANSI
American National Standards Institute
API
Application Programming Interface
ARJ
File compression format
ASF
Advanced Streaming Format
ATM
Asynchronous Transfer Mode
Technology for high speed data transfer
AVI
Audio Video Interleaved
Digital movie format
CAGIS
Cooperative Agents in a Global Information Space
CD-i
Compact Disc – interactive
A multimedia CD format specified in 1986
CDMA
Code Division Multiple Access
A digital spread-spectrum wireless technology
CDPD
Cellular digital packet data
A digital cellular standard used in some smart phones. Transmission rates
are limited to 19.2 kb/s.
B-1
CEPT
European Conference of Postal and Telecommunications Administrations
cHTML
Compact HTML
CLDC
Connected Limited Device Configuration
CSD
Circuit Switched Data
A data transmission service that used circuit switched communication
channels. For GSM systems, this has a maximum transfer rate of 14.4 kb/s
CODEC
Coder/Decoder
DECT
Digital European Cordless Telecommunication.
A cordless telephone system
DHCP
Dynamic Host Configuration Protocol
DSSS
Direct Sequence Spread Spectrum
DTD
Document Type Definition
EDGE
Enhanced Data for Global Evolution: A technology that increases available
time slots and data rates over existing wireless networks.
EPOC
Lightweight operating system developed by Psion and Symbian.
EPOS
Expert System for Program and System Development
ETSI
European Telecommunication Standards Institute
FDD
Frequency Division Duplex
FHSS
Frequency Hopping Spread Spectrum
FPS (fps)
Frames Per Second
GIF
Graphics Interchange Format:
GPRS
General Packet Radio System: An addition to GSM technology, it is a
protocol for sending and receiving data packets over a digital wireless
network. It is considered an efficient use of limited bandwidth and is
particularly suited for sending and receiving small bursts of data.
GSM
Global System for Mobile Communications: A digital wireless standard
used widely in Europe
GSM1800
GSM network operating in the 1800 MHz frequency band. Primarily used in
urban areas in Europe.
GSM1900
GSM network operating in the 1900 MHz frequency band. Primarily used in
urban areas in the US.
GSM900
GSM network operating in the 900 MHz frequency band. The original GSM
frequency band.
B-2
H.323
H.323-recommendation: Defines multimedia and communications
algorithms and protocols for IP networks
HIPERLAN
High Performance Radio Local Area Network
HIPERLAN/2
High Performance Radio Local Area Network - Short Range Variant
HomeRF
A digital wireless communications protocal designed for the transport of
voice and multimedia content between consumer electronic devices
including PCs in a residential setting. Operates at 2.4 Ghz
HRPD
HSCSD
High Rate Packet Data
High Speed Circuit Switched Data: An upgrade of CSD for GSM networks,
which gives a maximum transfer rate of 57.6 kb/s
HSDPA
HTTP
High Speed Downlink Packet Access
HyperText Transfer Protocol
IEC
International Engineering Consortium
IEEE
Institute of Electrical and Electronics Engineers
IETF
Internet Engineering Task Force
i-Mode
i-Mode is the packet-based service for mobile phones offered by Japan's
leader in wireless technology, NTT DoCoMo.
IMT-2000
International Mobile Telecommunication 2000
IP
Internet Protocol: A communication protocol common in the equipment that
makes out the Internet
IPv6
Internet Protocol version 6: A new version of IP that extends the address
space and adds new features.
IrDA
The Infrared Data Association
Infrared data transfer protocol
IS-136
American implementation of TDMA
IS-95A/B
Circuit Switched Data Services for CDMA
ISDN
Integrated Services Digital Network
ISO
International Organisation for Standardization
ISP
Internet Service Provider
ITU
International Telecommunications Union
J2ME
Java 2 Micro Edition
JPEG
Joint Photographic Expert Group Compression Standard
Compression standard for pictures, developed by ISO and ITU
B-3
LAN
Local Area Network
MBR
Multiple Bit Rate encoding
MBS
Mobile Broadband System
MC1x
Upgrade of cdmaOne to allow bit rates of 144 kb/s
MIDI
Musical Instrument Digital Interface
MIDP
Mobile Information Device Profile
MMS
Multimedia Messaging Service
MOWAHS
Mobile WOrk Across Heterogeneous Systems
MP3
MPEG1 Layer 3
MPEG
Moving Picture Experts Group
NAT
NMT
Network Address Translation
Nordic Mobile Telephone
Analogue mobile phone system used in Finland, Sweden, Denmark,
Norway and Iceland. NMT operated in the 450 MHz and 900 MHz-bands.
NTSC
National Television Standards Committee
Encoding of video signals used in North America
OS
Operating System
PAL
Television standard used in most of Europe
PCMCIA
Personal Computer Memory Card International Association
PDA
Personal Digital Assistant
PDC
Personal Digital Communications
A digital mobile phone standard used in Japan.
PIM
Personal Information Manager
PSTN
Public Switched Telephone Network:
QoS
Quality of Service
QoS states the user’s view of a certain service and is defined by a range of
technical parameters.
RTP
Real Time Protocol
SGML
Standard Generalized Markup Language
SMIL
Synchronized Multimedia Integration Language
A language enabling the transmission of several media streams to be
transferred individually, and being presented as if it were a single media
stream.
B-4
SMS
Short Message System - SMS messages
SVCD
Super Video CD
TCP
Transmission Control Protocol
TD/CDMA
Time Division/Code Division Multiple Access
TDD
Time Division Duplex.
TDMA
Time Division Multiple Access
A digital cellular technology that works by subdividing a radio signal to
handle multiple calls. It is a component of GSM cellular phones.
TIA
Telecommunications Industry Association
UDP
User Datagram Protocol
UMTS
Universal Mobile Telephone System
A third generation technology for faster transfer of data and multimedia
over wireless devices, mainly based on WCDMA.
URL
Uniform Resource Locator
An addressing system used on the Internet
VCD
Video CD
VPN
Virtual Private Network
VR
W3C
Virtual Reality
World Wide Web Consortium
A consortium of many Internet related businesses with the goal of
promoting WWW-technology standardization.
WAP
Wireless Application Protocol
A standard for communication between wireless Net devices. Global de
facto standard for browser services on mobile phone microbrowsers.
WAV
Microsoft Windows audio file format
WCDMA
Wideband Code Division Multiple Access
A third-generation mobile communications protocol similar to GSM that is
expected to provide enough bandwidth for wireless multimedia
applications.
WCDMA-DS
Wideband Code Division Multiple Access Direct Spread
WECA
Wireless Ethernet Compatibility Alliance
Wi-Fi
IEEE 802.11b
Wi-Fi5
IEEE 802.11a
B-5
WLAN
Wireless Local Access Network
This type of network allows wireless access to an Ethernet network using
some WLAN device and access points.
WMA
Windows Media Audio
WMV
Windows Media Video
WML
Wireless Markup Language
The markup language developed for and used in the Wireless Application
Protocol (WAP).
WPAN
Wireless Personal Area Network
WSI
Wireless Strategic Initiative
WWAN
Wireless Wide Area Network
WWW
World Wide Web
XML
eXtensible Markup Language
ZIP
File compression format
B-6
Appendix C - Technical information
QuickTime
These are the standard formats and codecs supported in QuickTime [65].
Video codecs
Audio codecs
H.261
H.263
Animation
Apple BMP
Apple Video
Cinepak
Component video
DV NTSC and PAL
Graphics (Apple)
Microsoft OLE
Microsoft Video 1
Motion JPEG A and B
Photo JPEG
Planar RGB
Sorenson Video 1, 2, and 3
24-bit integer
32-bit floating point
32-bit integer
64-bit floating point
ALaw 2:1
AU
IMA 4:1
MACE 3:1
MACE 6:1
MS ADPCM
QDesign Music 2
Qualcomm PureVoice
Import File Formats
Export file formats
3DMF
AIFF
AU
Audio CD Data
AVI
BMP
Cubic VR
DLS
DV
FlashPix
FLC
GIF
JPEG/JFIF
Karaoke
MacPaint
Macromedia Flash 4
MIDI
MPEG1
MP3
M3U (MP3 playlist)
Photoshop (.psd)
PICS
PICT
PLS
PNG
QuickTime Image File
QuickTime Movie (.mov)
SoundFont 2 (SF2)
SGI
Sound
Targa
Text
TIFF
TIFF Fax
Virtual Reality (QuickTime VR)
Wave
AIFF
AU
AVI
BMP
DV Stream
FLC
Image sequence
JPEG/JFIF
MacPaint
MIDI
Photoshop
PICT
PNG
QuickTime Image
QuickTime Movie
SGI
System 7 Sound
Targa
Text
TIFF
WAV
D-1
Windows Media Player
File type information for Windows Media Player for Pocket PC:
Supported If They Are Encoded in a
Supported Manner
Not Supported in Any Way
.wma (playback and stream)
.wmp (playback and stream)
.wmv (playback and stream)
.asf (playback and stream)
.mp3 (playback only, no stream)
any Real Audio format
any Apple, Inc. QuickTime format
anything uncompressed
any multi-cast only
mp3 playlists (.m3u, .pl, and so on)
AVI
AVR
MPEG1 (.mpg)
MIDI (.mid) 3dmf
AIFF
AU
Supported Redirect Files (Must Point at
Supported Data Files)
.asx
.wax
.wmx
.wmp
.wm
.wx
Supported Codecs
Not Supported
.mp3 (Fraunhoffer)
.wma (all iterations, version 2, version 7, and
version 8 codecs)
.MPEG4 (version 2, version 3, iso codecs)
.wmv (version 7, version 8)
JPEG motion
Apple Inc. QuickTime
Sorenson Video
Any Apple Inc. video Format
Supported Transport Protocols
Not Supported
http
HTTP Proxy
mms
mmst
mmsu
rtp
rtsp
D-2
Appendix D – Pictures
Figures 52 to 59 show more pictures and screen captures done during the testing and
evaluation of media player applications.
Figure 52 - Screenshots of Monsters Inc. trailer played on RealOne Player
Figure 53 - Clip information for two different bit rate versions of the
Monsters Inc. trailer
D-1
Figure 54 - Video clip in windowed and full screen mode in RealOne Player
Figure 55 - Pictures from PocketTV, a Star Wars trailer and file information for the trailer
D-2
Figure 56 – Screenshots from PocketTV, video and info about video clip
Figure 57 - Windows Media Player playing an MP3 music file and MP3 file info
D-3
Figure 58 - 56 Kb/s video clip and clip info in Windows Media Player
Note that the screen shots of figures 58 and 59 have been manipulated, where the video
pictures were taken with a digital camera and superimposed on the original screen captures
which only showed a black field where the video was played.
Of course, when playing the files everything worked fine, it was only the screen capturing
process that was not entirely successful.
Figure 59 - 256 Kb/s video clip and clip info in Windows Media Player
D-4

hovedoppgave - Department of Computer and Information Science

Transcription

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