OFDM and MC-CDMA A Primer

Transcription

OFDM and MC-CDMA
A Primer
L. Hanzo
University of Soutlmmpton. UK
T. Keller
Analog Devices Ud.. Cambridge. UK
OAI HOC OUdC GlA MA N6*
TRUNG TAM T H O N G T»N THU VI^N
A-Do/f^19
^lEEE
IEEE PRESS
IEEE Cofwnwiieaton* SooMy Sponaw
John WUey & Sons, Ltd
Contents
About the Authors
XV
Other Wiley and IEEE Press Books on Related Topics
xvli
Acknowledgements
xix
1
Introduction
I
1.1
Motivation of the Book
I
1.2
Orthogonal Frequency Division Multiplexing History
1.2.1 Early Classic Contributions and OFDM Standards
1.2.2 Peak-to-Mean Power Ratio
1.2.3 Synchronisation
1.2.4 OFDM/CDMA
1.2.5 Decision-Directed Channel Estimation
1.2.6 Uplink Detection Techniques for Multi-User SDMA-OFDM
1.2.7 OFDM Applications
Outline of the Book
Chapter Summary'and Conclusion
1.3
1.4
5
5
6
8
8
8
13
'^
j^
19
1 OFDM System Design
2
Introduction to Orthogonal Frequency Division Multiplexing
2.1 Introduction
2.2 Principles of QAM-OFDM
2.3 Modulation by DFT
2.4 Transmission via Bandlimited Channels
2.5 Basic OFDM Mtxiem Implementations
^ 6 Cyclic OFDM Symbol Extension
I ? Decision-Directed Adaptive Channel Equalisation
2.8 OFDM Bandwidth Efficiency
2.9 Chapter Summary and Conclusion
vii
21
23
[ . . . . . 25
29
32
33
3(,
3^
39
VIII
CONTENTS
3
O F D M Transmission over (;aussian Channels
3.1 Orthogonal Frequency Division Multiplexing . . . .
3.2 Choiceof the OFDM Modulation
3.3 OFT)M System Performance over AWGN Channels
3.4 Clippmg Amplification
3.4.1 OFDM Signal Amplitude Statistics
3.4.2 Clipping Ampliher Simulations
3.5
3.6
3.7
4
. . '
3.4.2.1
Introduction to Peak-Power Reduction Techniques
3.4.2.2
BER Performance Using Clipping Amplirters
3.4.2.3
Signal Spectrum with Clipping Ampliher
3.4.3 Clipping Amplification - Summary
Analogue-lo-Digilal Conversion
Phase Noise
3.6.1
Effects of Phase Noise
3.6.2
Phase Noise Simulations
3.6.2.1
White Phase Noise Model
3.6.2.1.1
Serial Modem
3.6.2.1.2
OFDM Modem
3.6.2.2
Coloured Phase Noise Model
3.6.3 Phase Noise - Summary
Chapter Summary and Conclusion
O F D M Transmission over Wideband Channels
4.1 The Channel Model
4.1.1 The Wireless Asynchronous Transfer Mode System
4.1.1.1
The WATM Channel
4.1.1.2
The Shortened WATM Channel
."
4.1.2 The Wireless Local Area Network
4.1.2.1
The WLAN Channel
4.1.3 UMTS System
4.1.3.1
The UMTS Type Channel
4.2 Effects ofTime-Dispersive Channels on OFDM
4.2.1 Effectsof the Stationary Time-Dispersive Channel
4.2.2 Non-Stationary Channel
4.2.2.1
Summar>'of Time-Variant Channels
4.2.3 Signalling over Time-Dispcrsive OFDM Channels
4.3
4.4
Channel Transfer Function Estimation
4.3.1 Frequency Domain Channel Transfer Function Estimation
4.3.1.1
Pilot Symbol-Assisted Schemes
4.3.1.1.1
Linear Interpolation for PSAM
4.3.1.1.2
Ideal Lowpass Interpolation for PSAM
4.3.1.1.3
Summary
4.3.2 Time Domain Channel EMimaiion
System Performance
AAA
Static Time-Dispci so e Channel
4.4.1.1
Perfect Channel Estimation
^*
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44
45
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47
^Q
5Q
53
53
54
54
55
55
57
60
60
61
61
62
62
64
64
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CONTENTS
4.4.1.2
4.4.^
4.5
4.6
Differentiallv Coded Modulation
^lo^*> Varying Time-Dispersive Channel . .
4.4.2.1
Perfect Channel Estimation
. . . ^
4.4.2.2
Pilot Symbol-Assisted Modulation Summary
Intersubcarrier Interference Cancellation
4.5.1 Motivation
4.5.2 The Signal Model
4.5.3 Channel Estimation
4.5.4 Cancellation Schemes
4.5.5 ICl Cancellation Performance
4.5.6 Conclusions on ICl Cancellation
'
• . »3
^*
!!
OFDM Time and Frequency Domain Synchronisation
5.1 System Performance with Frequency and Timing Errors
5.1.1
Frequency Shift
5.1.1.1
The Spectrum of the OFDM Signal
5.1.1.2
Effects of Frequency Mismatch on Different Modulation
Schemes
5.1.1.2.1
Coherent Modulation
5.1.1.2.2
Pilot Symbol Assisted Modulation
5.1.1.2.3
Differential Modulation
5.1.1.2.4
Frequency Error - Summary
5.1.2 Time Domain Synchronisation Errors
5.1.2.1
Coherent Demodulation
5.1.2.2
Pilot Symbol-Assisted Modulation
5.1.2.3 Differential Modulation
5.1.2.3.1
Time Domain Synchronisation Errors - Summarv'
5.2
^
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103
103
103
104
108
108
108
109
109
HO
'10
^
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Synchronisation Algorithms
5.2.1 Coarse Frame and OFDM Symbol Synchronisation Review
n^
5.2.2 Fine Symbol Tracking Review
^^^
5.2.3 Frequency Acquisition Review
^^^
5.2.4 Frequency Tracking Review
^^^
5.2.5 Synchronisation based on Auto-Correlation
^^^
5.2.6 Multiple Access Frame Structure
^^^
5.2.6.1 The Reference Symbol
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5 2 6 2 The Correlation Functions
^^
5.2.7 Frequency Tracking and OFDM Symbol Synchronisation
• ^-^
5.2.7.1 OFDM Symbol Synchronisation
^^^
5-> 7 2 Frequency Tracking Studies
- * ' ' .'
|22
5.2.8 FrequencyAcquisitionandFrameSynchronisationStud.es . . . . • • ^^^
5.2.8.1
Frame Synchronisation Studies
.122
S282
Frequency Acquisition Studies
. - ,
'
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5 2 8 3 Block Diagram of the Synchronisat.on Algon.hms . • • ^ ^ ^
5.2.9 Frequency Acquisition Using Pilots
CONTENTS
5.2.9.1
5.2.9.2
5.2.9.3
5.3
5.4
5.5
5.6
The Reference Symbol
Frequency Acquisition
Perfomiance of the Pilot-Based Frequency Acquisition in
AWGN Channels
5.2.9.4 Alternative Frequency Error Estimation for Frequency Domain Pilot Tones
Comparison of the Frequency Acquisition Algorithms
BER Performance with Frequency Synchronisation
Appendix: OFDM Synchronisation Performance
5.6.1 Frequency Synchronisation in an AWGN Channel
5.6.1.1 One Phasor in AWGN Environment
5.6.1.1.1
Cartesian Coordinates
5.6.1.1.2
Polar Coordinates
5.6.1.2 Product of Two Noisy Phasors
5.6.1.2.1
Joint Probability Density
5.6.1.2.2
Phase Distribution
5.6.1.2.3
Numerical Integration
Adaptive Single- and Multi-user OFDM Techniques
6.1 Introduction
6.1.1 Motivation
6.1.2 Adaptive Techniques
6.1.2.1
Channel Quality Estimation
6.1.2.2
Parameter Adaptation
6.1.2.3 Signalling the AOFDM Parameters
6.1.3 System Aspects
6.2 Adaptive Modulation for OFDM
6.2.1 System Model
6.2.2 Channel Model
6.2.3 Channel Transfer Function Variations
6.2.4 Choice of the Modulation Modes
6.2.4.1
FixedThreshold Adaptation Algorithm
6.2.4.2
Sub-Band BER Estimator Adaptation Algorithm
6.2.5 Constant Throughput Adaptive OFDM
6.2.6 AOFDM Mode Signalling and Blind Detection
6.2.6.1
Signalling
6.2.6.2
Blind Detection by SNR Estimation
6.2.6.3 Blind Detection by Multi-Mode Trellis Decoder
6.2.7 Sub-Band Adaptive OFDM and Turbo Channel CcKling
6.2.8 Effects of the Doppler Frequency
6.2.9 Channel Transfer Function Estimation
6.3 Adaptive OFDM Speech System
6.3.1 Inuoduclion
6.3.2 System Overview
6.3.2.1
System Parameters
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139
139
139
140
140
141
141
145
145
145
146
147
148
148
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169
.169
CONTENTS
6.3.3
6.3.4
6.3.5
Constant Throughput Adaptive Modulation
6.3.3.1 Constant-Rate BER Performance
Multimodc Adaptation
6.3.4.1 Mode Switching
Simulation Results
6.3.5.1 Frame Error Results
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173
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6.4
6.3.5.2 Audio Segmental SNR
Pre-equalisation
176
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6.4.1 Motivation
6.4.2 Pre-equalisation with Sub-Band Blocking
6.4.3 Adaptive Modulation with Spectral Predistortion
6.5 Comparison of the Adaptive Techniques
6.6 Near-Optimum Power-and Bit Allocation in OFDM
6.6.1 State of the An
6.6.2 Problem Description
6.6.3 Power and Bit Allocation Algorithm
6.7 Multi-User AOFDM
6.7.1 Introduction
6 7 2 Adaptive Transceiver Architecture
p^
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I(i4
186
186
186
187
*91
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192
6.7.2.1 An Overview
6.7.2.2 The Signal Model
6.7.2.3 The SMI Algorithm
6.7.2.4 The Adaptive Bit-Assignment Algorithm
6 7 2.5 The Channel Models
6.7.3 Simulation Results - Perfect Channel Knowledge
6 7 3 1 General Remarks
6 7*3 2 Two-Branch Maximum-Ratio Combining
6 7*3 3 SMI Co-Channellnlert'erence Suppression
6 7 4 Pilot-Based Channel Parameter Estimation
6.7.4.1 System Descnpuon
6 7 4.2 Simulation Results
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200
201
203
n
7
OFDM versus MC-CDMA Systems
OFDM versus MC-CDMA
pp^
7,2
The OFDM Component
7 2 Multi-Carrier CDMA
• 7 2 1 MC-CDMA
7'V^ MC-DS-CDMA • • •
,;2.3 M-rCDMA . . ^ ^ ^ ^ ^ ^ ^ ^
7.3 Further Research T o p u : ^ . ^ ^
7.4 Chapter Summary and Loi
^^^
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••
• • • • ; . ,
205
^05
211
214
.215
216
. . , . . . . . • , . . 2.7
. . . .
Basic Spreading Se<|ucnrrs
8.1 PN Sequencer
8.2
83
8 11 Maximalixngih Sequences
8.1.2 Gold Codes
8 1.3 Kasami Sequences
....
Onh(»ponal Codes
8 2 1 WaKhCiHles . . . .
8.2.2 OnhoyonainoM Codes . . . .
8 2 3 Multi Kale Orthogonal Cold Codes
Chapter Summar> and (OnclusMin
~~~~^
219
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219
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222
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MC.( DM \ IVrforniance in Synchronous KnMroiinunts
M.I Ihe l-requenc) Selecii\e Channel M*»del . . . . .
9.2 The S\stcm Mi>del
. ..[[
233
9.3 Single I'ser IX-ieclion
235
9.3.1 Maximal Ratio Comhining
9.3.2 liqual Gain Combining
2)9
9.3.3 OnhogonaliiN Restoring Combining
^41
9.4 MuJli-lêr Detection
i^,
9.4.1 Background
-iî
9.4.2 Maximum Likelihood Detection
24^
9.4.3 Concatenated Space-Time Block Coded and Turtx) Ccxied Svinholhy-Symhol Adaptive OFDM and Multi-Carrier (T)MA
244
9.5 Chapter Summar) and Conclusion
250
III
Advanced Topics: Multi-User OFDM Systems
10 Mtf\imum-Likelih(M>d Knhanci^ Sphi-n* [>ec(Kling of MIMO-OFDM
10.1 Cla.viihcalion of Smart Antennas
10.2 IntrtKJuction to Space-Time Processing
10.3 SDM-OKDMS) stem Model
10.3.1 MIMO Channel Model
10 3.2 SDM-OFDM Transceiver Structure
10.4 Optimised Hierarch> Reduced Search Algonihm Aided SDM [Vit%tum
10.4 I OHRSA-Aided Ml. SDM I>icclion
10.4 2 Search Strategy
10 4 2 1 Gcneralisalkw ol the OHRSA Ml SDM IVieû.r
10.4.3 BitwiMT OHRSA ML SDM DeicciM>n
10 4.3.1 GcncraJisjiion of the BW-OHRSA ML SDM lVtcctt»f
10 4 4 OHRSA Aided Log MAP SDM lViciiii>n
104 5 StiflOuipoi OHRSA Aiikd Appruxinwlc Log V« AP nruxiu>fi
10 4.5 1 Cumplexil) .AHJIVMN
10 4 5 2 Performance An*Jv4l^
10.5 Owptcr Summary and Conclu^fcHin
251
153
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26^
272
.77
_79
'^^
^^
CONTENTS
~
^
11 C;enetic Algorithm Aided Joint Channel Estimation and MUD
for SOMA OFDM
11.1 Introduction
m
303
303
3^^
^ ",
11.2 SOMA MIMO Channel Model
11.3 System Overview
M)t)
11.4 GA-Aided Iterative Joint Channel Hstimation and Multi-User Detection
306
11.4.1 Pilot-Aided Initial Channel Estimation
3QQ
11.4.2 Generating Initial Symbol Estimates
311
11.4.3 GA-Aided Joint FD-CHTF and Data Optimisation Providing Soft
Outputs
313
11.4.3.1 Extended GA Individual Structure for MIMO Systems . . . 313
11.4.3.2 Initialisation
314
11.4.3.3 Joint Genetic Optimisation
315
11.4.3.3.1 Cross-Over Operator
315
11.4.3.3.2 Mutation Operator
316
11.4.3.3.3 Comments on the Joint Optimisation Process . . 317
11.4.3.4 Generating the GA^s Soft Outputs
317
11.5 Simulation Results
319
11.5.1 Effectsof the Maximum Mutation Step Size
320
11.5.2 Effectsof the Doppler Frequency
323
11.5.3 Effects of the Number of GA-JCEMUD Iterations
324
11.5.4 Effects of the Pilot Overhead
325
11.5.5 Joint Optimisation versus Separate Optimisation
325
115 6 Comparison of GA-JCEMUDs Having Soft and Hard Outputs . . . . 327
327
11.5.7 MIMO Robustness
12 Multi-User OFDM Employing Genetic Algorithm Aided Minimum Bit Error^^^
Rate Multi-User Detection
12.1 Introduction
12.1.1 Minimum Bit Error Ratio Detection of OFDM
12.2 System
12.2.1
12.2.2
12.2.3
Model
Space Division Multiple Access
Error Probability of a BPSK System
Exact MBER Multi-User Detection
^^^
332
• ^^^
. . . 332
^^^
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" * ^ ^ ^ 33g
12.3 Genetic Algorithm
'
12.3.1 Overview of GAs
. \ \ i c o \ 4 A O F D M System
12.3.2 Employing GAS in the MBER MUD Aided SOMA OFDM Sy.
339
- 341
^^^
12.4 Simulation Results
' '. ' * A„,^nnaScenario . • 342
12.4.1 Performance of a Four-User and ^^^^^^^'^^^^^^^^^^
12.4.2 Performance of the Four-Antenna Scenario versus the Nu
^^^
of Users
12.5 Complexity Comparison . . .
-346
.346
—
CWTEvrg
13 Conclusion and Further Research Problems
13.1 Summan, and Conclusions of Part 1
13.1.1 Summar> of Part 1
13.1.2 Conclusions of Part 1
13.2 Summar> and Conclusions of Part II
13.2.1 Summarv of Part II
13.2.2 Conclusions of Part II
13.3 Summarv and Conclusions of Pan 111
13.3.1 Near-ML Enhanced Sphere Detection of MIMO-OFDM
13.3.2 GA-Aided Joint MUD and Channel Estimation
13.3.3 GA-Aided MBER MUD
13.4 Closing Remarks
^..
-.-.
^"i^.
^(^-,
^^^
3*^3
353
354
354
355
355
356
Glossary
3S9
Bibliography
343
Subject Index
W5
Author Index
401

OFDM and MC-CDMA A Primer

Transcription

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