LTE-Advanced Evolution in Releases 12

Nokia Networks
LTE-Advanced Evolution in
Releases 12 - 14
New services to pave the way to 5G
Nokia Networks white paper
LTE-Advanced Evolution in Releases 12 - 14
Contents
Introduction
3
Internet of Things (IoT)
4
Public safety
5
Broadcast services
6
Vehicular communication
8
Enhanced radio capabilities
9
Summary
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Introduction
The use of 3G and 4G networks has increased tremendously in recent years
and the rapid evolution of mobile broadband will continue with 5G technology.
The commercial 5G era is expected to start by 2020. 5G will bring enhanced
radio capabilities and enable new uses and applications beyond traditional
smartphones, tablets and laptops. Many of these uses can also be provided
on top of LTE-Advanced networks in order to pave the way to the 5G era.
LTE will be a cost-effective and high performance solution to meet the needs
of new vertical segments. Separate radio networks were previously required
to provide public safety services, terrestrial TV or machine-to-machine while
a single radio solution, LTE, will be able to deliver all those use cases. LTE will
also enable new uses like vehicle communication. LTE, and later 5G, will be the
mainstream connectivity solution. Therefore, network performance, coverage
and reliability need to match the requirements of all these future uses.
The new uses and corresponding LTE technologies are summarized in Figure 1.
The enhanced radio capabilities are summarized in Figure 2. This paper
gives an overview of the new features with LTE-Advanced evolution in 3GPP
Releases 12 to 14.
Internet of things
Public safety
Proximity services
Terrestrial TV
LTE-M
= Machine-to-Machine
LTE for Public Safety
LTE-D
= Device-to-Device
LTE-B
= Broadcast = eMBMS
Vehicle communication
LTE for V2X (Vehicle-to-X) communication
Connectivity for public
transport
LTE for Backhauling Wi-Fi access points
Figure 1. New uses on top of LTE-Advanced networks
Enhanced radio
capabilities
Denser networks
More spectrum
Beyond 1 Gbps data rate and low latency
Small cell optimization and
dual connectivity
LTE on Unlicensed Band (LTE-U)
License Assisted Access (LAA)
Figure 2. Enhanced radio capabilities with LTE-Advanced
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Internet of Things (IoT)
The Internet of Things (IoT) refers to interconnection and the autonomous
exchange of data between devices which are machines or parts of machines,
also called sensors. The number of IoT objects is expected to grow to 50 Bn.
IoT uses Machine-to-Machine (M2M) communications. M2M is defined as data
communication between devices without the human interaction. This may
be data communication between devices and a server, or device-to-device
either directly or over a network. Examples of M2M services include security,
tracking, payment, smart grid and remote maintenance and monitoring. M2M
requirements have been considered in the design of LTE and the following
optimizations are included for LTE:
• Low cost modem
• Long battery life
• Enhanced coverage
• Congestion control
The current LTE modems target high performance with peak data rates of 150
to 300 Mbps. Many M2M applications work well with much lower data rates.
3GPP has defined a lower device category in Release 12 (Category 0) and a
further reduced category is under work in Release 13. Modem implementation
in Release 12 costs less with lower data rate requirements, with single antenna
reception, no Multiple Input Multiple Output (MIMO) and half duplex. Two
reception antennas were mandatory for all LTE devices before Category 0.
Half duplex transmission allows some RF filters to be avoided since there is
no simultaneous transmission and reception. Release 13 will further reduce
the bit rate requirement. The device transmission bandwidth will be reduced
to 1.4 MHz, the maximum output power will be lowered and the highest
modulation schemes are excluded. The new device category will still be able
to access legacy LTE networks with minor updates. Backwards compatibility
is important to enable new M2M modems take advantage of existing LTE
networks for wide area coverage.
Table 1. Low cost device categories in Releases 12 and 13
Release 8
Release 8
Release 12
Release 13
Cat-4
Cat-1
Cat-0
Under work
Downlink peak rate
150 Mbps
10 Mbps
1 Mbps
1 Mbps
Uplink peak rate
50 Mbps
5 Mbps
1 Mbps
1 Mbps
Downlink spatial layers
2
1
1
1
UE RF receiver chains
2
2
1
1
Full duplex
Full duplex
Half duplex
Half duplex
UE receive bandwidth
20 MHz
20 MHz
20 MHz
1.4 MHz
Maximum UE transmit power
23 dBm
23 dBm
23 dBm
~20 dBm
Duplex mode
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Long battery life is useful for smartphone users, but even more important
for M2M applications that should be able to run for as much as 10 years
without the battery needing to be charged. A device power saving mode was
introduced in Release 12. The device is not reachable in the power saving
mode as it does not check paging. The device remains in power saving mode
until the next mobile-originated transaction takes place. Extending the DRX
cycle from 2.56 s to 2 min would also reduce the power consumption. It is
expected that 10 year battery life can be obtained with these solutions when
using two AA batteries.
Many M2M applications are located indoors or in basements, like smart
metering or industrial use cases. However, losses caused by indoor
penetration can create unreliable network connections. Therefore, the link
budget optimization is preferred for M2M. The target in LTE is to enhance M2M
coverage to allow more than 155 dB path loss. The coverage is typically uplink
limited due to limited device transmission power. Therefore, the optimization
is aimed at the uplink control channel PUCCH and data channels PUSCH.
The main solutions are Power Spectral Density (PSD) boosting, repetition,
retransmission and more retransmissions. Figure 3 shows the path loss for
data, voice and M2M
Max path loss [dB]
165
160
155
dB
150
145
140
135
LTE data
LTE VoLTE
LTE-M target
Figure 3. Maximum path loss with LTE M2M
Public safety
Current public safety networks such as TETRA or Project 25 (P25) support
mission critical voice communication, but are limited to narrowband data.
Mobile broadband can significantly help emergency services, for example live
mobile video, situation-aware dispatching and remote diagnostics. LTE will
provide public safety data transfer first, followed at a later stage by voice.
Public safety service with LTE can be obtained in two different ways
• on top of commercial LTE networks, or
• on a dedicated frequency and dedicated LTE network
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The activity started in USA 2012 when FirstNet won the responsibility
to coordinate the use of Band 14 (at 700 MHz) and many other
governments are proceeding to use LTE networks for public safety. In
the UK, the intention is to select an existing mobile operator to offer
LTE network services for public safety users. The same LTE network can
also be used for railway traffic management between trains and railway
control centers.
The LTE standard, Releases 12 and 13, includes new solutions for public
safety. Nokia took key rapporteurships in 3GPP to drive the vision into
the standards. The basic technology components, like prioritization
and emergency calls, are already available in Releases 8-11. Proximity
services (Device-to-device, or D2D) are included in Release 12 and
enhanced D2D in Release 13. Also, group communications is included
in Release 12 and mission critical push-to-talk in Release 13.The 3GPP
features are summarized in Figure 4.
Releases 8-10
Release 11
Release 12
Release 13
•
•
•
•
•
• High power UEs for Band 14
• Proximity services
• Group communication
• Enhanced proximity services
• Mission critical Push-to-Talk
• Isolated E-UTRAN operation
VoLTE
QoS
Ciphering
eMBMS
E911
Figure 4. 3GPP features for public safety
Broadcast services
Streaming video makes up a large part of LTE network traffic, revealing
that customers enjoy video content on their smartphones and tablet
computers. Unicast video transmission allows subscribers to receive any
content any time independent of other users. Broadcast and multicast
transmission has also been defined for LTE. The solution is called
enhanced Multimedia Broadcast Multicast Services (eMBMS). Multiple
devices can receive the same content with eMBMS as shown in Figure 5.
eMBMS also enhances the cell edge performance when multiple cells
transmit the same content using Single Frequency Network (SFN)
technology. The principle is illustrated in Figure 6. The broadcast
transmission is more efficient than unicast when multiple customers
want to receive the same content simultaneously, such as during sports
events or popular TV shows. Multi-cell transmission further improves the
efficiency when the inter-cell interference is turned into a constructive
signal. LTE broadcast is built to be flexible: it is possible to switch
between broadcast and unicast transmission and it is possible to share
the LTE frequency between broadcast and unicast.
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Unicast transmission
Broadcast transmission
Separate transmissions to each device
Single transmission received by all devices
Figure 5. Broadcast benefit for multiple receivers
Single cell
transmission
Multi -cell
broadcast
= Signal
= Interference
Other cell transmission is
interference
Other cell transmission is
useful signal
Figure 6. Multi-cell broadcast with single frequency network for enhanced cell
edge performance
eMBMS could be used for local transmission but can also provide wide
area TV transmission, potentially replacing high tower, high power Digital
Terrestrial TV (DTT) in the long term. The benefits of eMBMS compared
to terrestrial TV include:
• Provide broadcast content to smartphones and tablet computers
instead of only TV sets
• Provide better indoor coverage when using existing LTE sites
• Higher spectral efficiency when using low tower LTE sites
• Flexibility to switch between broadcast and unicast, improving
spectrum usage
If the TV broadcast is carried by mobile networks, more devices could
receive TV content, which is important because more people are using
smartphones and tablets to watch video. LTE networks can also provide
good indoor coverage which enables more customers to receive the
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content while terrestrial TV reception is typically designed for rooftop
antennas. LTE eMBMS can improve the spectral efficiency compared
to high tower terrestrial TV transmission because interference is
minimized with lower transmission towers. LTE also allows capacity
to be switched dynamically between broadcast and unicast based on
instantaneous requirements. Nokia has tested eMBMS technology
for TV broadcast on the 700 MHz frequency band in Germany. The
studies show that eMBMS can deliver TV content with similar costs
as terrestrial TV, yet provide more flexibility and higher spectral
efficiency.
A number of eMBMS enhancements can be included into future 3GPP
releases to further boost large area broadcast, including dedicated
eMBMS carrier and longer cyclic prefix.
Vehicular communication
Vehicular communication (V2X) has many uses, including navigation
and driver assistance, travel information, congestion avoidance, fleet
management, payment transactions and for traffic control and safety.
V2X communication may occur in multiple contexts: vehicle to vehicle
(V2V) communication, vehicle to infrastructure (V2I) communication,
vehicle to pedestrian (V2P) communication and vehicle to home
communication. These uses are referred to as Intelligent Transport
Systems (ITS). V2X applications range from personal communication,
green transportation, societal mobility and safety to bring more travel
convenience, comfort and safety.
LTE radio can be efficiently used for vehicular communication because
of its inherent radio capabilities.
• LTE networks have extensive coverage for urban and rural roads
• LTE provides low latency
• LTE has high capacity
• LTE allows direct D2D communication which can be used between
vehicles
• LTE modems are already integrated into many vehicles for other
reasons, like entertainment systems.
LTE enhancements improve LTE usage for vehicular communications
including D2D communication, Nokia Liquid Applications and
broadcast. The idea of Liquid Applications is to cache local information
in the base station to reduce latency in the transmission between
vehicles and network. The downlink broadcast can be used to deliver
messages to multiple vehicles at the same time. Figure 7 illustrates
Liquid Applications and broadcast solutions.
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Broadcast
Liquid
Apps
Figure 7. Liquid Applications and
downlink broadcast for optimized
vehicle communication
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Enhanced radio capabilities
New vertical uses will benefit from improved radio capabilities.
LTE technology will be enhanced in three domains: higher radio
performance, more cells and more spectrum. LTE-Advanced improves
radio performance to pave the road to future 5G networks. Radio
performance will be improved with
• More bandwidth
• Interference cancellation
• 3D beamforming
• Lower latency
Release 10 defined carrier aggregation with up to five component
carriers while Release 13 extended this to make it possible to take
advantage of more spectrum in terms of data rates and capacity.
Interference cancellation is an effective way to improve spectral
efficiency by removing co-channel interference. This becomes more
feasible with more powerful radio modems. Spectral efficiency can also
be improved with antenna solutions like 3-dimensional beamforming.
LTE-Advanced makes is easier to add new small cells. Small cell
optimization improves the co-existence between macro and small cells
including dual connectivity and inter-site carrier aggregation where
the device can receive data simultaneously from macro cells and small
cells. The concept is shown in Figure 8. Small cells and macro cells are
not operating as different layers but as a joint solution to provide the
maximal benefit for the device.
Inter-site carrier aggregation and dual connectivity
Macro cell
X2 interface
Small cell
Figure 8. Inter-site carrier aggregation and dual connectivity
LTE can access more spectrum between the 700 MHz and 5.4 GHz
bands. The new spectrum in many markets includes the 700 MHz
band and deployment has already started in Asia Pacific, supplemental
downlink at 1500 MHz, TDD 2300 MHz and 3500 MHz. An overview of
the spectrum options is shown in Figure 9.
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5400
5 GHz unlicensed band in small cells
3500
2600
3.5 GHz in small cells or macro cells
with aggregation
2300
2100
Spectrum aggregated into single
pool
1800
1500
900
800
700
Convergence of mobile broadband
and broadcast
470 – 700
Figure 9. LTE spectrum usage in typical European market
Release 13 also defines LTE deployment on the 5 GHz unlicensed
band. The solution combines lower frequency LTE from licensed bands
with the 5 GHz unlicensed band. The solution is called LTE Unlicensed
(LTE-U) or License Assisted Access (LAA). LTE technology provides
high performance on the unlicensed band because of advanced radio
solutions. The typical cell range at 5 GHz band is illustrated in Figure 10.
Outdoor micro cell range
Wi-Fi (5 GHz)
Min
Max
LTE (5 GHz)
0
50
100
150
200
Meters
Figure 10. License Assisted Access (LAA) cell range in small cells
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Summary
A number of new uses can be supported by mobile networks including
connectivity for Internet of Things (IoT), public safety, broadcast
services and vehicular connectivity. These uses will benefit from LTEAdvanced features in 3GPP Releases 12-14. The power of LTE lies in
the massive ecosystem and wide area coverage which will provide a
highly cost-effective solution. The same radio network can be used for
smartphones, tablets computers and laptops, and for many other uses.
The new capabilities will be simple to upgrade to existing LTE networks.
LTE-Advanced paves the way into the 5G era in the next decade.
Further reading
LTE-Advanced white paper
LTE Release 12 white paper
LTE-M white paper
LTE Public safety white paper
LTE Broadcast press release
Nokia Liquid Apps
LTE Unlicensed spectrum
5G Requirements White Paper
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