Ofdm and Mc-Cdma for Broadband Multi-User Communications, Wlans and Broadcasting

by Hanzo, Lajos; M¿nster, M.; Choi, Byungcho; Keller, Thomas

• ISBN13: 9780470858790
• ISBN10: 0470858796
• Edition: 1st
• Format: Hardcover
• Copyright: 2003-09-11
• Publisher: Wiley-IEEE Press

Summary

Orthogonal frequency-division multiplexing (OFDM) is a method of digital modulation in which a signal is split into several narrowband channels at different frequencies.CDMA is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimising the use of available bandwidth. Multiplexing is sending multiple signals or streams of information on a carrier at the same time in the form of a single, complex signal and then recovering the separate signals at the receiving end.Multi-Carrier (MC) CDMA is a combined technique of Direct Sequence (DS) CDMA (Code Division Multiple Access) and OFDM techniques. It applies spreading sequences in the frequency domain. Wireless communications has witnessed a tremendous growth during the past decade and further spectacular enabling technology advances are expected in an effort to render ubiquitous wireless connectivity a reality. This technical in-depth book is unique in its detailed exposure of OFDM, MIMO-OFDM and MC-CDMA. A further attraction of the joint treatment of these topics is that it allows the reader to view their design trade-offs in a comparative context. Divided into three main parts: Part I provides a detailed exposure of OFDM designed for employment in various applicationsPart II is another design alternative applicable in the context of OFDM systems where the channel quality fluctuations observed are averaged out with the aid of frequency-domain spreading codes, which leads to the concept of MC-CDMAPart III discusses how to employ multiple antennas at the base station for the sake of supporting multiple users in the uplink Portrays the entire body of knowledge currently available on OFDM Provides the first complete treatment of OFDM, MIMO(Multiple Input Multiple Output)-OFDM and MC-CDMA Considers the benefits of channel coding and space time coding in the context of various application examples and features numerous complete system design examples Converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems Combines the benefits of a textbook with a research monograph where the depth of discussions progressively increase throughout the book This all-encompassing self-contained treatment will appeal to researchers, postgraduate students and academics, practising research and development engineers working for wireless communications and computer networking companies and senior undergraduate students and technical managers.

Author Biography

Lajos Hanzo received his degree in electronics in 1976 and his doctorate in 1983. During his career in telecommunications he has held various research and academic posts in Hungary, Germany and the UK. Since 1986 he has been with the&#160; Department of Electronics and Computer Science, University of Southampton, UK, where he holds the chair in telecommunications. Lajos is also an IEEE Distinguished Lecturer of both the Communications as well as the Vehicular Technology Society and a Fellow of the IEE. <p> Matthias M&#252;nster was awarded the Dipl. Ing. degree by the RWTH Aachen, Germany and after graduation he embarked on postgraduate research at the University of Southampton, where he completed his PhD in mobile communications on 2002. His areas of interest include adaptive multiuser OFDM transmission, wideband channel estimation, multiuser detection and a range of related signal processing aspects. <p> Byoung-Jo Choi received his BSc and MSc degrees in Electrical Engineering from KAIST, Korea, in 1990 and 1992, respectively. He was awarded his PhD degree in Mobile Communications at the University of Southampton, UK, where he was a postdoctoral research assistant. His current research interests are related to mobile communication systems design with emphasis on adaptive modulation aided OFDM, MC-CDMA and W-CDMA. <p> Thomas Keller studied Electrical Engineering at the University of Karlsruhe, Ecole Superieure d'Ingenieurs en Electronique et Electrotechnique, Paris and the University of Southampton. He completed his PhD at the University of Southampton and his areas of interest include adaptive OFDM transmission, wideband channel estimation, CDMA and error correction coding.

Table of Contents

About the Authors	xxix
Other Wiley and IEEE Press Books on Related Topics	xxxi
Acknowledgments	xxxiii
1 Introduction	1	(20)
1.1 Motivation of the Book	1	(4)
1.2 Orthogonal Frequency Division Multiplexing History	5	(11)
1.2.1 Early Classic Contributions	5	(1)
1.2.2 Peak to-mean Power Ratio	6	(1)
1.2.3 Synchronisation	7	(1)
1.2.4 OFDMICDMA	7	(1)
1.2.5 Decision-Directed Channel Estimation	8	(5)
1.2.6 Detection Techniques for Multi-User SDMA-OFDM	13	(1)
1.2.7 OFDM Applications	13	(3)
1.3 Outline of the Book	16	(3)
1.4 Chapter Summary and Conclusion	19	(2)
I OFDM System Design	21	(218)
2 Introduction to OFDM	23	(28)
2.1 Introduction	23	(2)
2.2 Principles of QAM OFDM	25	(2)
2.3 Modulation by DFT	27	(5)
2.4 Transmission via Bandlimited Channels	32	(2)
2.5 Generalised Nyquist Criterion	34	(5)
2.6 Basic OFDM Modem Implementations	39	(2)
2.7 Cyclic OFDM Symbol Extension	41	(1)
2.8 Reducing MDI by Compensation	42	(4)
2.8.1 Transient System Analysis	42	(2)
2.8.2 Recursive MDI Compensation	44	(2)
2.9 Decision-Directed Adaptive Channel Equalisation	46	(1)
2.10 OFDM Bandwidth Efficiency	47	(2)
2.11 Chapter Summary and Conclusion	49	(2)
3 OFDM Transmission over Gaussian Channels	51	(24)
3.1 Orthogonal Frequency Division Multiplexing	52	(2)
3.1.1 History	52	(4)
3.1.1.1 Peak-to-Mean Power Ratio	53	(1)
3.1.1.2 Synchronisation	53	(1)
3.1.1.3 OFDMICDMA	54	(1)
3.1.1.4 Adaptive Antennas	54	(1)
3.1.1.5 OFDM Applications	54	(1)
3.2 Choice of the OFDM Modulation	54	(1)
3.3 OFDM System Performance over AWGN Channels	55	(1)
3.4 Clipping Amplification	56	(7)
3.4.1 OFDM Signal Amplitude Statistics	56	(1)
3.4.2 Clipping Amplifier Simulations	57	(5)
3.4.2.1 Introduction to Peak-Power Reduction Techniques	58	(1)
3.4.2.2 BER Performance Using Clipping Amplifiers	59	(1)
3.4.2.3 Signal Spectrum with Clipping Amplifier	60	(2)
3.4.3 Clipping Amplification Summary	62	(1)
3.5 Analogue-to-Digital Conversion	63	(2)
3.6 Phase Noise	65	(7)
3.6.1 Effects of Phase Noise	66	(1)
3.6.2 Phase Noise Simulations	66	(6)
3.6.2.1 White Phase Noise Model	67	(1)
3.6.2.1.1 Serial Modem	67	(1)
3.6.2.1.2 OFDM Modem	67	(3)
3.6.2.2 Coloured Phase Noise Model	70	(2)
3.6.3 Phase Noise -Summary	72	(1)
3.7 Chapter Summary and Conclusion	72	(3)
4 OFDM Transmission over Wideband Channels	75	(42)
4.1 The Channel Model	75	(5)
4.1.1 The Wireless Asynchronous Transfer Mode System	76	(2)
4.1.1.1 The WATM Channel	76	(2)
4.1.1.2 The Shortened WATM Channel	78	(1)
4.1.2 The Wireless Local Area Network	78	(1)
4.1.2.1 The WLAN Channel	79	(1)
4.1.3 UMTS System	79	(1)
4.1.3.1 The UMTS Type Channel	79	(1)
4.2 Effects of Time Dispersive Channels on OFDM	80	(4)
4.2.1 Effects of the Stationary Time Dispersive Channel	81	(1)
4.2.2 Non Stationary Channel	82	(2)
4.2.2.1 Summary of Time-variant Channels	84	(1)
4.2.3 Signalling over Time-Dispersive OFDM Channels	84	(1)
4.3 Channel Transfer Function Estimation	84	(8)
4.3.1 Frequency Domain Channel Transfer Function Estimation	85	(7)
4.3.1.1 Pilot Symbol-Assisted Schemes	85	(1)
4.3.1.1.1 Linear Interpolation for PSAM	85	(1)
4.3.1.1.2 Ideal Lowpass Interpolation for PSAM	89	(1)
4.3.1.1.3 Summary	89	(3)
4.3.2 Time Domain Channel Estimation	92	(1)
4.4 System Performance	92	(14)
4.4.1 Static Time-Dispersive Channel	92	(11)
4.4.1.1 Perfect Channel Estimation	93	(2)
4.4.1.2 Differentially Coded Modulation	95	(3)
4.4.1.3 PSAM Aided Channel Transfer Function Estimation	98	(5)
4.4.2 Slowly Varying Time Dispersive Channel	103	(3)
4.4.2.1 Perfect Channel Estimation	104	(1)
4.4.2.2 Pilot Symbol Assisted Modulation Summary	104	(2)
4.5 Intersubcarrier Interference Cancellation	106	(10)
4.5.1 Motivation	106	(3)
4.5.2 The Signal Model	109	(1)
4.5.3 Channel Estimation	110	(2)
4.5.4 Cancellation Schemes	112	(1)
4.5.5 ICI Cancellation Performance	113	(1)
4.5.6 Conclusions on ICI Cancellation	114	(2)
4.6 Chapter Summary and Conclusion	116	(1)
5 Time and Frequency Domain Synchronisation	117	(42)
5.1 Performance with Frequency and Timing Errors	117	(12)
5.1.1 Frequency Shift	117	(7)
5.1.1.1 The Spectrum of the OFDM Signal	118	(4)
5.1.1.2 Effects of Frequency Mismatch on Different Modulation Schemes	122	(1)
5.1.1.2.1 Coherent Modulation	122	(1)
5.1.1.2.2 Pilot Symbol Assisted Modulation	123	(1)
5.1.1.2.3 Differential Modulation	123	(1)
5.1.1.2.4 Frequency Error - Summary	123	(1)
5.1.2 Time Domain Synchronisation Errors	124	(5)
5.1.2.1 Coherent Demodulation	125	(1)
5.1.2.2 Pilot Symbol-Assisted Modulation	125	(1)
5.1.2.3 Differential Modulation	126	(1)
5.1.2.3.1 Time Domain Synchronisation Errors - Summary	128	(1)
5.2 Synchronisation Algorithms	129	(18)
5.2.1 Coarse Frame and OFDM Symbol Synchronisation Review	130	(1)
5.2.2 Fine Symbol Tracking Review	130	(1)
5.2.3 Frequency Acquisition Review	130	(1)
5.2.4 Frequency Tracking Review	131	(1)
5.2.5 Synchronisation by Auto-correlation	131	(1)
5.2.6 Multiple Access Frame Structure	131	(3)
5.2.6.1 The Reference Symbol	132	(1)
5.2.6.2 The Correlation Functions	133	(1)
5.2.7 Frequency Tracking and OFDM Symbol Synchronisation	134	(2)
5.2.7.1 OFDM Symbol Synchronisation	134	(1)
5.2.7.2 Frequency Tracking Studies	134	(2)
5.2.8 Frequency Acquisition and Frame Synchronisation Studies	136	(2)
5.2.8.1 Frame Synchronisation Studies	136	(1)
5.2.8.2 Frequency Acquisition Studies	136	(1)
5.2.8.3 Block Diagram of the Synchronisation Algorithms	137	(1)
5.2.9 Synchronisation Using Pilots	138	(15)
5.2.9.1 The Reference Symbol	138	(1)
5.2.9.2 Frequency Acquisition	138	(3)
5.2.9.3 Performance of the Pilot-Based Frequency Acquisition in AWGN Channels	141	(4)
5.2.9.4 Alternative Frequency Error Estimation for Frequency Domain Pilot Tones	145	(2)
5.3 Comparison of the Frequency Acquisition Algorithms	147	(4)
5.4 BER Performance with Frequency Synchronisation	151	(1)
5.5 Chapter Summary and Conclusion	152	(1)
5.6 Appendix: OFDM Synchronisation Performance	153	(6)
5.6.1 Frequency Synchronisation in an AWGN Channel	153	(6)
5.6.1.1 One Phasor in AWGN Environment	153	(1)
5.6.1.1.1 Cartesian Coordinates	153	(1)
5.6.1.1.2 Polar Coordinates	153	(1)
5.6.1.2 Product of Two Noisy Phasors	154	(1)
5.6.1.2.1 Joint Probability Density	154	(1)
5.6.1.2.2 Phase Distribution	155	(1)
5.6.1.2.3 Numerical Integration	155	(4)
6 Adaptive Single- and Multi-user OFDM	159	(60)
6.1 Introduction	159	(5)
6.1.1 Motivation	159	(1)
6.1.2 Adaptive Techniques	160	(4)
6.1.2.1 Channel Quality Estimation	161	(1)
6.1.2.2 Parameter Adaptation	162	(1)
6.1.2.3 Signalling the AOFDM Parameters	162	(2)
6.1.3 System Aspects	164	(1)
6.2 Adaptive Modulation for OFDM	164	(19)
6.2.1 System Model	164	(1)
6.2.2 Channel Model	165	(1)
6.2.3 Channel Transfer Function Variations	166	(1)
6.2.4 Choice of the Modulation Modes	166	(4)
6.2.4.1 Fixed Threshold Adaptation Algorithm	167	(2)
6.2.4.2 Sub-band BER Estimator Adaptation Algorithm	169	(1)
6.2.5 Constant Throughput Adaptive OFDM	170	(2)
6.2.6 AOFDM Mode Signalling and Blind Detection	172	(5)
6.2.6.1 Signalling	172	(2)
6.2.6.2 Blind Detection by SNR Estimation	174	(1)
6.2.6.3 Blind Detection by Multi-Mode Trellis Decoder	175	(2)
6.2.7 Sub-band Adaptive OFDM and Turbo Channel Coding	177	(2)
6.2.8 Effects of the Doppler Frequency	179	(1)
6.2.9 Channel Transfer Function Estimation	179	(4)
6.3 Adaptive OFDM Speech System	183	(8)
6.3.1 Introduction	183	(1)
6.3.2 System Overview	183	(2)
6.3.2.1 System Parameters	184	(1)
6.3.3 Constant Throughput Adaptive Modulation	185	(3)
6.3.3.1 Constant-Rate BER Performance	186	(2)
6.3.4 Multimode Adaptation	188	(1)
6.3.4.1 Mode Switching	188	(1)
6.3.5 Simulation Results	189	(2)
6.3.5.1 Frame Error Results	189	(1)
6.3.5.2 Audio Segmental SNR	190	(1)
6.4 Pre-equalisation	191	(8)
6.4.1 Motivation	191	(4)
6.4.2 Pre-equalisation with Sub-band Blocking	195	(1)
6.4.3 Adaptive Modulation with Spectral Predistortion	196	(3)
6.5 Comparison of the Adaptive Techniques	199	(2)
6.6 Near-optimum Power- and Bit-allocation in OFDM	201	(4)
6.6.1 State of the Art	201	(1)
6.6.2 Problem Description	201	(1)
6.6.3 Power and Bit Allocation Algorithm	202	(3)
6.7 Multi User AOFDM	205	(11)
6.7.1 Introduction	206	(1)
6.7.2 Adaptive Transceiver Architecture	206	(4)
6.7.2.1 An Overview	206	(1)
6.7.2.2 The Signal Model	207	(1)
6.7.2.3 The SMI Algorithm	208	(1)
6.7.2.4 The Adaptive Bit-assignment Algorithm	209	(1)
6.7.2.5 The Channel Models	209	(1)
6.7.3 Simulation Results - Perfect Channel Knowledge	210	(5)
6.7.3.1 General Remarks	210	(1)
6.7.3.2 Two-Branch Maximum Ratio Combining	210	(1)
6.7.3.3 SMI Co-Channel Interference Suppression	210	(5)
6.7.4 Pilot-based Channel Parameter Estimation	215	(4)
6.7.4.1 System Description	215	(1)
6.7.4.2 Simulation Results	215	(1)
6.8 Chapter Summary and Conclusion	216	(3)
7 Block-Coded Adaptive OFDM	219	(20)
7.1 Introduction	219	(1)
7.1.1 Motivation	219	(1)
7.1.2 Choice of Error Correction Codes	220	(1)
7.2 Redundant Residue Number System Codes	220	(11)
7.2.1 Performance in an AWGN channel	222	(7)
7.2.1.1 Performance in a fading time dispersive channel	223	(1)
7.2.1.2 Adaptive RRNS-coded OFDM	223	(6)
7.2.2 ARRNS/AOFDM Transceivers	229	(2)
7.2.3 Soft Decision RRNS Decoding	231	(1)
7.3 Turbo BCH Codes	231	(4)
7.3.1 Adaptive TBCH Coding	233	(1)
7.3.2 Joint ATBCH/AOFDM Algorithm	234	(1)
7.4 Signalling	235	(1)
7.5 Chapter Summary and Conclusion	236	(3)
II OFDM versus MC-CDMA Systems, Their Spreading Codes and Peak Factor Reduction	239	(240)
8 OFDM versus MC-CDMA	241	(14)
8.1 Amalgamating DS-CDMA and OFDM	241	(6)
8.1.1 The DS-CDMA Component	241	(3)
8.1.2 The OFDM Component	244	(3)
8.2 Multi-Carrier CDMA	247	(5)
8.2.1 MC-CDMA	247	(3)
8.2.2 MC-DS-CDMA	250	(2)
8.2.3 MT CDMA	252	(1)
8.3 Further Research Topics in MC-CDMA	252	(1)
8.4 Chapter Summary and Conclusion	253	(2)
9 Basic Spreading Sequences	255	(12)
9.1 PN Sequences	255	(4)
9.1.1 Maximal Length Sequences	255	(2)
9.1.2 Gold Codes	257	(1)
9.1.3 Kasami Sequences	258	(1)
9.2 Orthogonal Codes	259	(6)
9.2.1 Walsh Codes	259	(1)
9.2.2 Orthogonal Gold Codes	260	(2)
9.2.3 Multi rate Orthogonal Gold Codes	262	(3)
9.3 Chapter Summary and Conclusion	265	(2)
10 MC-CDMA Performance in Synchronous Environments	267	(16)
10.1 The Frequency Selective Channel Model	268	(2)
10.2 The System Model	270	(1)
10.3 Single User Detection	271	(8)
10.3.1 Maximal Ratio Combining	272	(4)
10.3.2 Equal Gain Combining	276	(2)
10.3.3 Orthogonality Restoring Combining	278	(1)
10.4 Multi User Detection	279	(2)
10.4.1 Maximum Likelihood Detection	280	(1)
10.5 Chapter Summary and Conclusion	281	(2)
11 Advanced Peak Factor Reduction Techniques	283	(70)
11.1 Introduction	283	(2)
11.2 Measures of Peakiness	285	(1)
11.3 Special Sequences for Reducing Amplitude Variations	286	(9)
11.3.1 Shapiro-Rudin Sequences	286	(2)
11.3.2 Golay Codes	288	(1)
11.3.3 M-Sequences	289	(1)
11.3.4 Newman Phases and Schroeder Phases	290	(3)
11.3.5 Barker Codes	293	(1)
11.3.6 Comparison of Various Schemes	294	(1)
11.4 Crest Factor Reduction Mapping Schemes for OFDM	295	(5)
11.4.1 Some Properties of the Peak Factors in OFDM	295	(2)
11.4.2 CF-Reduction Block Coding Scheme	297	(2)
11.4.3 Selected Mapping-Based CF-Reduction	299	(1)
11.4.4 Partial Transmit Sequences	300	(1)
11.5 Peak Factors in Multi-Carrier CDMA	300	(35)
11.5.1 System Model and Envelope Power	301	(5)
11.5.2 Spreading Sequences and Crest Factors	306	(17)
11.5.2.1 Single-code Signal	306	(5)
11.5.2.2 Shapiro-Rudin-based Spreading Sequences	311	(9)
11.5.2.3 Peak Factor Distribution of Multi-Code MC-CDMA	320	(3)
11.5.3 Clipping Amplifier and BER Comparison	323	(11)
11.5.3.1 Non-linear Power Amplifier Model	323	(2)
11.5.3.2 Clipping Effects on Output Power	325	(2)
11.5.3.3 Effects of Clipping on the Bit Error Ratio	327	(5)
11.5.3.4 Clipping Effects on Frequency Spectrum	332	(2)
11.5.4 Diversity Considerations	334	(1)
11.6 Chapter Summary and Conclusion	335	(1)
11.7 Appendix: Peak-to-mean Envelope Power Ratio of OFDM Systems	336	(17)
11.7.1 PMEPR Analysis of BPSK Modulated OFDM	336	(1)
11.7.2 PMEPR Properties of BPSK Modulated OFDM	337	(11)
11.7.3 PMEPR Calculation of BPSK Modulated OFDM	348	(1)
11.7.4 PMEPR Properties of QPSK Modulated OFDM	349	(4)
12 Adaptive Modulation for OFDM and MC-CDMA	353	(78)
12.1 Introduction	353	(1)
12.2 Increasing the Average Transmit Power as a Fading Counter-Measure	354	(4)
12.3 System Description	358	(7)
12.3.1 General Model	359	(1)
12.3.2 Examples	359	(2)
12.3.2.1 Five-Mode AQAM	359	(1)
12.3.2.2 Seven-Mode Adaptive Star QAM	360	(1)
12.3.2.3 Five Mode APSK	360	(1)
12.3.2.4 Ten-Mode AQAM	361	(1)
12.3.3 Characteristic Parameters	361	(4)
12.3.3.1 Closed Form Expressions for Transmission over Nakagami Fading Channels	363	(2)
12.4 Optimum Switching Levels	365	(19)
12.4.1 Limiting the Peak Instantaneous BEP	366	(3)
12.4.2 Torrance's Switching Levels	369	(2)
12.4.3 Cost Function Optimisation as a Function of the Average SNR	371	(3)
12.4.4 Lagrangian Method	374	(10)
12.5 Results and Discussion	384	(32)
12.5.1 Narrow-band Nakagami-m Fading Channel	385	(17)
12.5.1.1 Adaptive PSK Modulation Schemes	385	(6)
12.5.1.2 Adaptive Coherent Star QAM Schemes	391	(7)
12.5.1.3 Adaptive Coherent Square QAM Modulation Schemes	398	(4)
12.5.2 Performance over Narrow-band Rayleigh Channels Using Antenna Diversity	402	(3)
12.5.3 Performance over Wideband Rayleigh Channels using Antenna Diversity	405	(3)
12.5.4 Uncoiled Adaptive Multi-Carrier Schemes	408	(3)
12.5.5 Concatenated Space-Time Block Coded and Turbo Coded Symbol by-Symbol Adaptive OFDM and Multi-Carrier CDMA	411	(5)
12.6 Chapter Summary and Conclusion	416	(1)
12.7 Appendix: Mode Specific Average BEP of Adaptive Modulation	417	(2)
12.8 Appendix: BER Analysis of Type-I Star-QAM	419	(10)
12.8.1 Coherent Detection	419	(10)
12.9 Appendix: Two-Dimensional Rake Receiver	429	(2)
12.9.1 System Model	429	(2)
12.9.2 BER Analysis of Fixed-mode Square QAM	431	(1)
13 Successive Partial Despreading Based Multi-Code MC-CDMA	431	(48)
13.1 Introduction	437	(1)
13.2 SystemModel	438	(2)
13.3 The Sequential Partial Despreading Concept	440	(3)
13.4 AWGN Channel	443	(14)
13.4.1 Type I Detector	444	(1)
13.4.2 Type II Detector	444	(6)
13.4.3 Type III Detector	450	(5)
13.4.4 Summary and Discussion	455	(2)
13.5 Effects of Impulse Noise or Narrow Band Jamming	457	(20)
13.5.1 Conventional BPSK System without Spreading	457	(1)
13.5.2 Conventional Despreading Scheme	457	(4)
13.5.3 SPD Detectors	461	(3)
13.5.4 The I Detector	464	(4)
13.5.5 Type II Detector	468	(3)
13.5.6 Type III Detector	471	(5)
13.5.7 Summary and Discussion	476	(1)
13.6 Chapter Summary and Conclusion	477	(2)
III Advanced Topics: Channel Estimation and Multi-user OFDM Systems	479	(432)
List of General Symbols	481	(430)
14 Pilot-Assisted Channel Estimation for Single-User OFDM	485	(64)
14.1 Introduction	485	(4)
14.1.1 Classification of Channel Estimation Techniques	487	(2)
14.2 The Stochastic Channel Model	489	(6)
14.2.1 Model of the Channel Impulse Response	490	(1)
14.2.2 Auto-Correlation Function of the CIR: rh (δt, T)	491	(1)
14.2.3 Spaced-Time Spaced-Frequency Correlation Function - Fourier Transform of the CIR's ACF with Respect to the Multipath Delay Variable: rH(δt,δf)	491	(1)
14.2.4 Fourier Transform of the CIR's ACF with Respect to the Multipath Delay- and Spaced-Time Variables: SH (f d, δf)	492	(1)
14.2.5 Scattering Function - Fourier Transform of the CIR's ACF with Respect to the Time-Delay: Sh (f d,T)	493	(1)
14.2.6 Separability of the Channel's Spaced-Time Spaced-Frequency Correlation Function	493	(2)
14.3 Channel Model for Monte Carlo Simulations	495	(1)
14.3.1 The Indoor WATM Model	495	(1)
14.4 Introduction to 2D-Signal Processing	496	(2)
14.4.1 Description of a 2D-Sequence by a Periodicity Matrix	496	(2)
14.5 Maximum Pilot-Distances for a Rectangular Pilot Grid	498	(2)
14.5.1 Sampling in the Frequency Direction	498	(1)
14.5.2 Sampling in the Time Direction	499	(1)
14.6 2D-Pilot Pattern-Assisted 2D-FIR Wiener Filter-Aided Channel Estimation	500	(16)
14.6.1 Derivation of the Optimum Estimator Coefficients and Estimator MSE for Matched and Mismatched Channel Statistics	500	(1)
14.6.1.1 Linear Channel Transfer Factor Estimate	501	(1)
14.6.1.2 Estimator MSE and Cost-Function	503	(1)
14.6.1.3 Optimum Estimator Coefficients and Minimum Estimator MSE	504	(1)
14.6.1.4 Estimator Coefficients for Mismatched Channel Statistics	505	(1)
14.6.2 Robust Estimator Design	505	(1)
14.6.2.1 Uniform Scattering Function and its Associated Spaced Time Spaced-Frequency Correlation Function	506	(1)
14.6.2.2 Relevance of the Shift-Parameter	507	(1)
14.6.2.3 Application to a Robust Estimator	507	(1)
14.6.3 Complexity Reduction	508	(1)
14.6.3.1 Number of Pilot Subcarriers in the Estimator's Input Block	508	(1)
14.6.3.2 Selection of Subsets of Pilot Subcarriers	509	(1)
14.6.4 MSE Performance of 2D-FIR Wiener Filtering	509	(1)
14.6.4.1 Simulation Parameters - Design of the Pilot Grid and the Uniform Scattering Function used in the Calculation of Filter Coefficients	510	(1)
14.6.4.2 Evolution of the Estimator MSE over a Period of the Rectangular Pilot Grid	512	(1)
14.6.4.3 Influence of the Pilot Grid Density and the Number of Filter Taps on the Estimator's MSE	513	(1)
14.6.5 Computational Complexity	514	(1)
14.6.6 Summary and Conclusion on 2D-FIR Wiener Filtering	515	(1)
14.7 Cascaded 1D FIR Wiener filtering	516	(28)
14.7.1 Derivation of the Optimum Estimator Coefficients and Estimator MSE for both Matched and Mismatched Channel Statistics	517	(1)
14.7.1.1 First-Stage Channel Estimates - Interpolation in the Frequency Direction	517	(1)
14.7.1.1.1 Linear Channel Transfer Factor Estimate	517	(1)
14.7.1.1.2 Estimator Coefficients for Mismatched Channel Statistics	518	(1)
14.7.1.1.3 Estimator MSE	518	(1)
14.7.1.2 Second-Stage Channel Estimates - Interpolation in the Time Direction	519	(1)
14.7.1.2.1 Linear Channel Transfer Factor Estimate	519	(1)
14.7.1.2.2 Estimator Coefficients for Mismatched Channel Statistics	520	(1)
14.7.1.2.3 Estimator MSE	521	(1)
14.7.1.3 Simplification of the Cascaded 1D-FIR Wiener Filter	522	(1)
14.7.2 MSE Performance of the Cascaded 1D-FIR Wiener Filter	522	(1)
14.7.2.1 Comparison to 2D-FIR Wiener Filtering	523	(1)
14.7.2.2 Misadjustment of Multipath- and Doppler Spread	525	(1)
14.7.2.3 Misadjustment of the SNR	526	(1)
14.7.2.4 Impact of Imperfect Synchronization	528	(1)
14.7.2.5 Mismatch of the Multipath Intensity Profile's Shape	532	(3)
14.7.3 MSE and BER Performance Evaluation by Monte Carlo Simulations	535	(1)
14.7.3.1 Simulation Parameters	536	(1)
14.7.3.2 MSE Simulation Results	538	(1)
14.7.3.3 BER Simulation Results	539	(1)
14.7.4 Complexity	540	(1)
14.7.4.1 Computational Complexity	540	(1)
14.7.4.2 Number of Coefficient Vectors per SNR Level for Decoupled Cascaded 1D-FIR Filters	541	(1)
14.7.5 Summary and Conclusion on Cascaded 1D-FIR Wiener Filtering	542	(2)
14.8 Chapter Summary and Conclusion	544	(1)
14.9 List of Symbols Used in Chapter 14	545	(4)
15 Decision-Directed Channel Estimation for Single-User OFDM	549	(70)
15.1 Introduction	549	(3)
15.2 Description	552	(21)
15.2.1 Decision-Directed A Posteriori Least-Squares Channel Estimation	553	(2)
15.2.2 Enhancement of the A Posteriori Least-Squares Channel Transfer Factor Estimates by One-Dimensional MMSE Estimation	555	(1)
15.2.2.1 Structure of the 1D-MMSE Channel Estimator	555	(1)
15.2.2.2 Estimator MSE for Mismatched Channel Conditions	557	(1)
15.2.3 Enhancement of the A Posteriori Least-Squares Channel Transfer Factor Estimates by Two-Dimensional MMSE Estimation	557	(1)
15.2.3.1 Structure of the 2D-MMSE Estimator	558	(1)
15.2.3.2 Estimator MSE for Mismatched Channel Statistics	558	(1)
15.2.3.3 Motivation of Time Direction Channel Prediction Filtering	561	(2)
15.2.4 MMSE A Priori Time Direction Channel Prediction Filtering	563	(1)
15.2.4.1 Linear Prediction of the CIR-Related Taps	564	(1)
15.2.4.2 Auto-Correlation Matrix and Cross-Correlation Vector of the CIR	565	(1)
15.2.4.3 Derivation of the Wiener Equation using the Gradient Approach	566	(1)
15.2.4.3.1 Gradient Approach	566	(1)
15.2.4.3.2 Orthogonality Principle	567	(1)
15.2.4.4 Optimum Predictor Coefficients and Minimum CIR-Related Domain Predictor MSE	567	(1)
15.2.4.5 Optimum Predictor Coefficients for Mismatched Channel Statistics	568	(1)
15.2.4.6 Average Channel Predictor MSE in the Frequency Domain	569	(1)
15.2.5 Channel Statistics for A Priori Time Direction Channel Prediction Filtering	570	(1)
15.2.5.1 Robust A Priori Time Direction Channel Prediction Filtering	571	(1)
15.2.5.1.1 Review of Robust Channel Estimation	571	(1)
15.2.5.1.2 Design of the Auto-Correlation Matrix and Cross-Correlation Vector of a Robust Channel Predictor	571	(1)
15.2.5.2 Adaptive A Priori Time Direction Channel Prediction Filtering	572	(1)
15.3 Performance of Decision-Directed Channel Prediction Aided-OFDM	573	(29)
15.3.1 MSE Performance of a Robust Decision-Directed Channel Predictor in the Context of Error-Free Symbol Decisions	574	(1)
15.3.1.1 MSE Performance under Matched Channel Conditions	575	(1)
15.3.1.2 MSE Performance under Mismatched Channel Conditions with Respect to the Doppler Frequency	575	(1)
15.3.1.3 MSE Performance under Mismatched Channel SNR Conditions	579	(1)
15.3.1.4 MSE Performance under Mismatched Multipath Spread Conditions	580	(1)
15.3.1.5 Conclusion on the MSE Performance of Robust Decision Directed Channel Prediction in the Context of Error-Free Symbol Decisions	581	(1)
15.3.2 MSE Performance of an Adaptive Decision-Directed Channel Predictor in the Context of Error-Free Symbol Decisions	581	(1)
15.3.2.1 MSE Performance under Matched Channel Conditions as a Function of the Number of Samples invoked in the Predictor Design	582	(1)
15.3.2.2 MSE Performance in Comparison to that of the Robust Channel Transfer Function Predictor	584	(1)
15.3.2.3 MSE Performance for Various Multipath Intensity Profiles	585	(1)
15.3.2.4 Conclusion on Adaptive Decision-Directed Channel Prediction in the Context of Error-Free Symbol Decisions	586	(1)
15.3.3 MSE Performance of a Robust Decision-Directed Channel Predictor in the Context of an Uncoded System	587	(1)
15.3.3.1 MSE Performance for a Frame-Invariant Fading Channel and for Error-Free Symbol Decisions	589	(1)
15.3.3.2 MSE Performance for a Frame-Invariant Fading Channel and Sliced Symbol Decisions	590	(1)
15.3.3.3 MSE Performance for a Frame-Variant Fading Channel and for Sliced Symbol Decisions	590	(1)
15.3.3.4 Conclusion on the MSE Performance of a Robust Decision Directed Channel Predictor	591	(1)
15.3.4 BER Performance of an Uncoded System Employing Robust Decision-Directed Channel Prediction	592	(1)
15.3.4.1 BER Performance for BPSK and QPSK	592	(1)
15.3.4.2 BER Performance for 16QAM	592	(1)
15.3.4.3 Conclusion on the BER Performance of an Uncoded System employing Robust Decision-Directed Channel Prediction	595	(1)
15.3.5 BER Performance of a Turbo-Coded System Employing Robust Decision-Directed Channel Prediction	595	(1)
15.3.5.1 Influence of the ICI Variance on the Subcarrier SNR	596	(1)
15.3.5.2 BER Performance for BPSK Modulation in the Context of an Undecoded Reference	596	(1)
15.3.5.3 BER Performance for QPSK Modulation and 16QAM in the Context of an Undecoded Reference	598	(1)
15.3.5.4 BER Performance for QPSK Modulation in the Context of a Decoded Reference	600	(1)
15.3.5.5 Conclusion on the BER Performance of a Turbo-Coded System Employing Robust Decision-Directed Channel Prediction	601	(1)
15.4 Robust Decision-Directed Channel Prediction-Assisted Adaptive OFDM	602	(9)
15.4.1 Transceiver Structure	603	(1)
15.4.1.1 Modulation Mode Adaptation	604	(1)
15.4.2 BER Performance	605	(1)
15.4.2.1 Motivation of Channel Transfer Function Prediction Assisted AOFDM	605	(1)
15.4.2.2 BER Performance of the Uncoiled System	607	(1)
15.4.2.3 BER Performance of the Turbo-Coded System	609	(1)
15.4.3 Conclusion on Robust Decision-Directed Channel Prediction Assisted AOFDM	610	(1)
15.5 Chapter Summary and Conclusion	611	(3)
15.5.1 Description	611	(1)
15.5.2 Performance Assessment	612	(1)
15.5.3 Adaptive OFDM Transceiver	613	(1)
15.6 List of Symbols Used in Chapter 15	614	(5)
16 Channel Estimation for Multi-User OFDM	619
16.1 Motivation	619	(3)
16.2 The SDMA Signal Model on a Subcarrier Basis	622	(1)
16.3 Multi-User Multiple Reception Antenna Aided OFDM	623	(1)
16.4 Least-Squares Error Decision-Directed Channel Estimation	624	(22)
16.4.1 Derivation of the LS-Estimator	625	(1)
16.4.1.1 The SDMA Signal Model on a Receiver Antenna Basis	625	(1)
16.4.1.2 Sub-Space-Based Approach	626	(1)
16.4.1.2.1 Low-Rank Approximation of the i-th User's Vector of Different Subcarriers' Channel Transfer Factors	626	(1)
16.4.1.2.2 Determination of the LS-DDCE Coefficients Using the Gradient Approach	627	(1)
16.4.1.2.3 Necessary Condition for Identification of the LSDDCE Coefficients	630	(1)
16.4.1.2.4 Implementation by QR Decomposition	630	(1)
16.4.2 Least-Squares Channel Estimation MSE in the Context of Both Sample-Spaced and Non-Sample-Spaced CIRs	631	(1)
16.4.2.1 Correlation Matrix of the Channel Transfer Factor Estimates	631	(1)
16.4.2.2 Sample-Spaced CIRs	633	(1)
16.4.2.2.1 Auto-Correlation Matrix of the Channel Transfer Factor Estimation Errors	633	(1)
16.4.2.2.2 Properties of Optimum Training Sequences ...	634	(1)
16.4.2.2.3 A Posteriori Estimation MSE Using Optimum Training Sequences	636	(1)
16.4.2.3 Non-Sample-Spaced CIRs	637	(1)
16.4.2.3.1 Cross-Correlation Matrix of the Channel Transfer Factor Estimates in the Context of Optimum Training Sequences	637	(1)
16.4.2.3.2 Auto-Correlation Matrix of the Channel Transfer Factor Estimates in the Context of Optimum Training Sequences	638	(1)
16.4.2.3.3 Channel Estimation MSE in the Context of Optimum Training Sequences	639	(1)
16.4.3 A Priori Channel Transfer Function Estimation MSE Enhancement by Linear Prediction of the A Posteriori CIR-Related Tap Estimates	640	(1)
16.4.4 Simplified Approach to LS-Assisted DDCE	640	(1)
16.4.5 Complexity Analysis of the Original- and Simplified LS-Assisted DDCE	641	(1)
16.4.5.1 Complexity of the Original LS-Assisted DDCE	641	(1)
16.4.5.1.1 Complexity Associated with Assembling Matrix Q [n]	642	(1)
16.4.5.1.2 Complexity Associated with Assembling Vector p[n]	643	(1)
16.4.5.1.3 Complexity Associated with Solving the LS System Equations for the Vector of CIR-Related Tap Estimates hapt,Ko [n]	643	(1)
16.4.5.1.4 Total Complexity	643	(1)
16.4.5.2 Complexity of the Simplified LS-Assisted DDCE	644	(1)
16.4.6 Conclusion on the Original and Simplified LS-Assisted DDCE	645	(1)
16.5 Frequency Domain Parallel Interference Cancellation Aided DDCE	646	(45)
16.5.1 The Recursive Channel Estimator	647	(1)
16.5.1.1 A Priori and A Posteriori Channel Estimates	647	(1)
16.5.1.2 A Priori Channel Prediction Filtering	649	(1)
16.5.1.3 A Priori Channel Estimation MSE	651	(1)
16.5.1.4 A Posteriori Channel Estimation MSE	653	(1)
16.5.1.5 Stability Analysis of the Recursive Channel Estimator	654	(1)
16.5.1.6 Iterative Calculation of the CIR-Related Tap Predictor Coefficients	656	(1)
16.5.1.6.1 Simplified Approach for Identical User Statistics	657	(1)
16.5.1.6.2 Closed Form Solution for Identical User Statistics and One-Tap CIR-Related Tap Prediction Filtering	658	(1)
16.5.1.7 Channel Statistics	659	(2)
16.5.2 Performance Assessment	661	(1)
16.5.2.1 Evolution of the A Priori Channel Estimation MSE in a Simplified 2-Tap CIR-Related Tap Prediction Scenario	661	(1)
16.5.2.2 A Priori Channel Estimation MSE in the Context of Ideal, Error-Free Symbol Decisions Assuming a Sample-Spaced CIR	662	(1)
16.5.2.2.1 Optimum Recursive versus Sub-Optimum Transversal CIR-Related Tap Predictor Coefficients - One Tap	663	(1)
16.5.2.2.2 Optimum Recursive- versus Sub-Optimum Transversal CIR-related Tap Predictor Coefficients - Higher Order	664	(1)
16.5.2.2.3 Influence of the Number of Simultaneous Users in the Context of the Optimum Recursive CIR Related Tap Predictor Coefficients	665	(1)
16.5.2.2.4 Influence of the OFDM Symbol Normalised Doppler Frequency	667	(1)
16.5.2.2.5 Influence of a Mismatch of the OFDM Symbol Normalised Doppler Frequency	668	(1)
16.5.2.2.6 Performance Comparison to Li's LS-Assisted DDCE	670	(1)
16.5.2.3 Effects of a Non-Sample Spaced CIR in the Context of Ideal, Error-Free Symbol Decisions	671	(1)
16.5.2.3.1 Sparse Profiles	672	(1)
16.5.2.3.2 Uniform Profiles	674	(1)
16.5.2.3.3 Exponential Profiles	675	(1)
16.5.2.3.4 A Priori Channel Estimation MSE for a NonSample Spaced CIR	676	(1)
16.5.2.3.5 A Priori Channel Transfer Factor Estimation MSE for a Non-Sample Spaced CIR on a Subcarrier Basis	678	(2)
16.5.2.4 A Priori Channel Estimation MSE and System BER in the Context of Imperfect, Error-Contaminated Symbol Decisions Assuming a Sample-Spaced CIR	680	(1)
16.5.2.4.1 Effects of Error-Contaminated Symbol Decisions	680	(1)
16.5.2.4.2 MSE and BER Performance in an Uncoiled Scenario	681	(1)
16.5.2.4.3 BER Performance in the Turbo-Coded Scenario	682	(2)
16.5.3 Computational Complexity	684	(1)
16.5.3.1 A Posteriori Channel Estimation Complexity	684	(1)
16.5.3.2 A Priori Channel Estimation Complexity	685	(1)
16.5.4 Summary and Conclusions	686	(1)
16.5.4.1 Summary and Conclusions on the PIC-Assisted DDCE's Structure	687	(1)
16.5.4.2 Summary and Conclusions on the Performance Assessment of the PIC-Assisted DDCE	688	(1)
16.5.4.2.1 Performance of the PIC-Assisted DDCE in the Context of Sample-Spaced CIRs and Error-Free Symbol Decisions	688	(1)
16.5.4.2.2 Performance of the PIC-Assisted DDCE in the Context of Non-Sample-Spaced CIRs and Error Free Symbol Decisions	689	(1)
16.5.4.2.3 Performance of the PIC-Assisted DDCE in the Context of Sample-Spaced CIRs and Imperfect, Error-Contaminated Symbol Decisions	690	(1)
16.5.4.3 Summary and Conclusions on the PIC-Assisted DDCE's Computational Complexity	690	(1)
16.6 RLS-Adaptive Parallel Interference Cancellation Aided DDCE	691	(9)
16.6.1 Single-User RLS-Adaptive CIR-Related Tap Prediction	692	(1)
16.6.1.1 Review of the RLS Algorithm	692	(1)
16.6.1.2 Potential Simplification by Ensemble Averaging	693	(1)
16.6.1.3 MSE Performance Assessment	694	(1)
16.6.1.4 Complexity Study	696	(1)
16.6.2 RLS-Adaptive PIC-Assisted DDCE for Multi-User OFDM	697	(1)
16.6.2.1 MSE Performance Assessment	697	(2)
16.6.3 Conclusion	699	(1)
16.7 Chapter Summary and Conclusion	700	(3)
16.8 List of Symbols Used in Chapter 16	703
17 Detection Techniques for Multi-User SOMA-OFDM	115	(734)
17.1 Introduction	715	(8)
17.1.1 Classification of Smart Antennas	715	(4)
17.1.2 Introduction to Space-Division-Multiple-Access	719	(1)
17.1.3 Classification of Multi-User Detection Techniques	719	(1)
17.1.4 Outline of Chapter 17	720	(2)
17.1.5 SDMA-MIMO Channel Model	722	(1)
17.2 Linear Detection Techniques	723	(28)
17.2.1 Characterisation of the Linear Combiner's Output Signal	724	(1)
17.2.1.1 Description of the Different Signal Components	725	(1)
17.2.1.2 Statistical Characterisation	725	(1)
17.2.1.3 Performance Measures	726	(1)
17.2.2 Least-Squares Error Detector	727	(1)
17.2.2.1 Simplified Model of the Received Signal	727	(1)
17.2.2.2 Least-Squares Error Cost-Function	727	(1)
17.2.2.3 Recovery of the Transmitted Signals by the Gradient Approach	728	(1)
17.2.2.4 Condition for Identification	729	(1)
17.2.2.5 Squared Estimation Error in the Received Signals' Domain	729	(1)
17.2.2.6 Mean-Square Estimation Error in the Transmitted Signals' Domain	730	(1)
17.2.3 Minimum Mean-Square Error Detector	730	(1)
17.2.3.1 Mean-Square Error Cost-Function	731	(1)
17.2.3.2 Recovery of the Transmitted Signals by the Gradient Approach	732	(1)
17.2.3.2.1 Right-Inverse Related Form of the MMSE Combiner	732	(1)
17.2.3.2.2 Left-Inverse Related Form of the MMSE Combiner	733	(1)
17.2.3.3 Mean-Square Estimation Error in the Transmitted Signals' Domain	734	(1)
17.2.3.4 Optimum Weight Vector in Standard Form	734	(1)
17.2.3.5 Relation between MMSE and MV Combining	735	(1)
17.2.4 Demodulation of the Different Users' Combiner Output Signals	736	(1)
17.2.4.1 Approximation of a Specific User's Combiner Output Signal as a Sample of a Complex Gaussian Distribution	736	(1)
17.2.4.2 Determination of a Specific User's Transmitted Symbol by Maximising the A Posteriori Probability	737	(1)
17.2.5 Generation of Soft-Bit Information for Turbo-Decoding	738	(1)
17.2.5.1 Simplification by Maximum Approximation	740	(1)
17.2.6 Performance Analysis	740	(1)
17.2.6.1 MSE and BER Performance Comparison of LS, MMSE and MVDR Detection	741	(1)
17.2.6.2 SINK Performance of MMSE Detection for Different Numbers of Users and Reception Antennas	743	(1)
17.2.6.3 BER Performance of MMSE Detection for Different Numbers of Users and Reception Antennas	744	(1)
17.2.6.4 BER Performance of Turbo-Coded MMSE Detection Assisted SDMA-OFDM	745	(1)
17.2.7 Complexity Analysis	746	(1)
17.2.7.1 LS Combining	746	(1)
17.2.7.1.1 LS Combining without Generating the Weight Matrix	746	(1)
17.2.7.1.2 LS Combining Generating the Weight Matrix	747	(1)
17.2.7.2 MMSE Combining	747	(1)
17.2.7.2.1 Left-Inverse Related Form of MMSE Combining without Generating the Weight Matrix	747	(1)
17.2.7.2.2 Left-Inverse Related Form of MMSE Combining Generating the Weight Matrix	748	(1)
17.2.7.3 Demodulation of the Linear Combiner's Output Signal	748	(1)
17.2.7.4 Simplified Complexity Formulae to be Used in the Comparison of the Different Detectors	749	(1)
17.2.8 Conclusion on Linear Detection Techniques	750	(1)
17.3 Non-Linear Detection Techniques	751	(62)
17.3.1 SIC Detection	752	(1)
17.3.1.1 Standard SIC	754	(1)
17.3.1.2 M-SIC and its Derivatives	757	(1)
17.3.1.2.1 M-SIC	758	(1)
17.3.1.2.2 Partial M SIC	758	(1)
17.3.1.2.3 Selective-Decision-Insertion Aided M-SIC	759	(1)
17.3.1.3 Generation of Soft-Bit Information for Turbo-Decoding	759	(1)
17.3.1.3.1 Generation of Rudimentary Soft-Bits	759	(1)
17.3.1.3.2 Generation of Weighted Soft-Bits	760	(1)
17.3.1.4 Performance Analysis	761	(1)
17.3.1.4.1 BER and SER Performance of Standard SIC and M-SIC for Different Numbers of Users and Receiver Antennas	763	(1)
17.3.1.4.2 SER Performance of Standard SIC and M-SIC on a Per-Detection Stage Basis	763	(1)
17.3.1.4.3 SER Performance of Standard SIC and M-SIC on a Per-Detection Stage Basis for an Error-Free Reference	764	(1)
17.3.1.4.4 Evaluation of the Error-Propagation-Related Event Probabilities	767	(1)
17.3.1.4.5 SER Performance of the Partial M-SIC	768	(1)
17.3.1.4.6 SER Performance of Selective-Decision-Insertion Aided M SIC	768	(1)
17.3.1.4.7 BER Performance of Turbo-Coded SIC Detection Assisted SDMA-OFDM	771	(1)
17.3.1.5 Complexity Analysis	772	(1)
17.3.1.5.1 Complexity of Standard SIC	772	(1)
17.3.1.5.2 Complexity of M-SIC	775	(1)
17.3.1.5.3 Complexity of Partial M-SIC	778	(1)
17.3.1.5.4 Complexity Comparison of the Different SIC Detectors	780	(1)
17.3.1.6 Summary and Conclusions on SIC Detection Techniques	781	(3)
17.3.2 PIC Detection	784	(1)
17.3.2.1 Uncoded PIC	784	(1)
17.3.2.2 Turbo-Coded PIC	788	(1)
17.3.2.3 Performance Analysis	790	(1)
17.3.2.3.1 BER Performance of Uncoded PIC Detection Assisted SDMA-OFDM for Different Numbers of Users and Receiver Antennas	790	(1)
17.3.2.3.2 BER Performance of Turbo-Coded PIC Detection Assisted SDMA-OFDM for Different Numbers of Users and Receiver Antennas	791	(2)
17.3.2.4 Complexity Analysis	793	(1)
17.3.2.5 Summary and Conclusions on PIC Detection	795	(1)
17.3.3 ML Detection	796	(1)
17.3.3.1 Standard ML Detection	797	(1)
17.3.3.1.1 Representation of the Vector of Received Signals as a Sample of a Multi-Variate Complex Gaussian Distribution Function	797	(1)
17.3.3.1.2 Determination of the Vector of Transmitted Symbols by Maximising the A Posteriori Probability	798	(1)
17.3.3.2 Transform-Based ML Detection	799	(1)
17.3.3.3 ML-Assisted Soft-Bit Generation for Turbo-Decoding	801	(1)
17.3.3.3.1 Standard ML-Assisted Soft-Bit Generation	801	(1)
17.3.3.3.2 Simplification by Maximum Approximation	802	(1)
17.3.3.4 Performance Analysis	803	(1)
17.3.3.4.1 BER Performance of ML Detection-Assisted SDMA-OFDM for Different Numbers of Users and Reception Antennas	803	(1)
17.3.3.4.2 BER Performance of Turbo-Coded ML Detection Assisted SDMA-OFDM for Different Numbers of Users and Reception Antennas	804	(1)
17.3.3.5 Complexity Analysis	805	(1)
17.3.3.5.1 Complexity of Standard ML Detection	806	(1)
17.3.3.5.2 Complexity of Transform-Based ML Detection	806	(1)
17.3.3.5.3 Complexity of ML-Assisted Maximum Approximation Based Soft-Bit Generation	807	(1)
17.3.3.6 Summary and Conclusions on ML Detection	808	(1)
17.3.4 Final Comparison of the Different Detection Techniques	809	(1)
17.3.4.1 BER Performance Comparison of the Different Detection Techniques in Uncoded and Turbo-Coded Scenarios	809	(1)
17.3.4.2 Complexity Comparison of the Different Detection Techniques	811	(2)
17.4 Performance Enhancement	813	(17)
17.4.1 Adaptive Modulation-Assisted SDMA-OFDM	813	(1)
17.4.1.1 Outline of the Adaptive Single-User Receiver	814	(1)
17.4.1.2 Outline of the Adaptive Multi-User SDMA-OFDM Receiver	814	(1)
17.4.1.3 Performance Assessment	816	(1)
17.4.1.4 Summary and Conclusions	818	(1)
17.4.2 Walsh-Hadamard Transform Spreading Assisted SDMA-OFDM	819	(1)
17.4.2.1 Outline of WHTS-Assisted Single User OFDM Receiver	819	(1)
17.4.2.1.1 Properties of the Walsh-Hadamard Transform	820	(1)
17.4.2.1.2 Receiver Design	821	(3)
17.4.2.2 Outline of the WHTS Assisted Multi-User SDMA-OFDM Receiver	824	(1)
17.4.2.3 Performance Assessment	826	(1)
17.4.2.3.1 Single-User WHTS-OFDM	826	(1)
17.4.2.3.2 Multi-User SDMA-WHTS-OFDM	828	(1)
17.4.2.4 Summary and Conclusions	829	(1)
17.5 Chapter Summary and Conclusion	830	(10)
17.5.1 Review of the Motivation for Multiple Reception Antenna SDMA Receivers	831	(1)
17.5.2 Summary and Conclusions Related to Linear Detectors	832	(1)
17.5.3 Summary and Conclusions Related to Non-Linear Detectors	833	(1)
17.5.3.1 SIC Detection	833	(1)
17.5.3.2 PIC Detection	835	(1)
17.5.3.3 ML Detection	836	(1)
17.5.3.4 Overall Comparison of the Different Detection Techniques	837	(1)
17.5.3.5 Summary and Conclusions Related to Performance Enhancement Techniques	838	(1)
17.5.3.5.1 Adaptive Modulation Assisted SDMA-OFDM	838	(1)
17.5.3.5.2 Walsh-Hadamard Transform Spreading Assisted SDMA OFDM	839	(1)
17.6 List of Symbols Used in Chapter 17	840	(9)
18 OFDM-Based Wireless Video System Design	849	(38)
18.1 Adaptive Turbo-coded OFDM-Based Videotelephony	849	(21)
18.1.1 Motivation and Background	849	(2)
18.1.2 AOFDM Modem Mode Adaptation and Signalling	851	(1)
18.1.3 AOFDM Sub-band BER Estimation	851	(1)
18.1.4 Video Compression and Transmission Aspects	852	(1)
18.1.5 Comparison of Sub-band-Adaptive OFDM and Fixed Mode OFDM Transceivers	852	(6)
18.1.6 Sub-band-Adaptive OFDM Transceivers Having Different Target Bit Rates	858	(4)
18.1.7 Time-Variant Target Bit Rate OFDM Transceivers	862	(8)
18.2 Multi-user OFDM/H.263 HIPERLAN-like Video Telephony	870	(10)
18.2.1 Overview	870	(1)
18.2.2 The Video System	871	(1)
18.2.2.1 OFDM Transceiver	871	(1)
18.2.2.2 Video Transmission Regime	873	(1)
18.2.3 The OFDM Signal Model	874	(2)
18.2.4 Co-Channel Interference Cancellation Techniques	876	(2)
18.2.5 Video System Performance Results	878	(2)
18.3 Chapter Summary and Conclusion	880	(7)
19 Conclusion and Further Research Problems	887	(24)
19.1 Summary of Part I	887	(2)
19.1.1 Summary of Part I	887	(1)
19.1.2 Conclusions of Part I	888	(1)
19.2 Summary and Conclusions of Part II	889	(9)
19.2.1 Summary of Part II	889	(2)
19.2.2 Conclusions of Part II	891	(7)
19.3 Summary and Conclusions of Part III	898	(10)
19.3.1 Pilot-Assisted Channel Estimation for Single-User OFDM	898	(1)
19.3.2 Decision-Directed Channel Estimation for Single-User OFDM	899	(1)
19.3.2.1 Complexity Reduction by CIR-Related Domain Filtering	900	(1)
19.3.2.2 Compensation of the Channel's Time-Variance by CIR Related Tap Prediction Filtering	901	(1)
19.3.2.3 Subject for Future Research: Successive Adaptivity of KLT and CIR-Related Tap Prediction Filtering	902	(1)
19.3.3 Channel Estimation for Multi-User SDMA-OFDM	903	(1)
19.3.3.1 LS Assisted DDCE	904	(1)
19.3.3.2 PIC-Assisted DDCE	904	(2)
19.3.4 Uplink Detection Techniques for SDMA-OFDM	906	(1)
19.3.4.1 SIC Detection	906	(1)
19.3.4.2 PIC Detection	907	(1)
19.3.4.3 Improvement of MMSE and PIC Detection by Adaptive Modulation or WHT Spreading	907	(1)
19.3.5 OFDM-Based Wireless Video System Design	907	(1)
19.4 Closing Remarks	908	(3)
Glossary	911	(4)
Bibliography	915	(34)
Subject Index	949	(16)
Author Index	965