Table Of ContentCOMA Techniques for Third Generation
Mobile Systems
CDMA Techniques for Third Generation
Mobile Systems
Edited by
Francis Swarts
Alcatel Research Unit for Wireless Access,
University of Pretoria, South Africa
Pieter van Rooyen
Alcatel Research Unit for Wireless Access,
Universityof Pretoria, South Africa
lan Oppermann
Center for Wireless Communication (CWC),
University of Oulu, Finland
Michiel P. Lătter
Alcatel Altech Telecoms, South Africa
Springer Science+Business Media, LLC
Library of Congress Cataloging-in-Publication
CDMA techniques for third generation mobile systems / edited by
Francis Swarts ... [et aL] .
p. cm. -- (The Kluwer international series in engineering and
computer science ; SECS 487)
IncIudes bibliographical references and index.
ISBN 978-1-4613-7321-6 ISBN 978-1-4615-5103-4 (eBook)
DOI 10.1007/978-1-4615-5103-4
1. Code division multiple access. 2. Mobile communication
systems. I. Swarts, Francis. II. Series.
TK5103.45.C36 1999
621.3845--dc21
98-45583
CIP
Copyright li> 1999 by Springer Science+Business Media New York
Originally published by Kluwer Academic Publishers, New York in 1999
Softcover reprint of the hardcover 1s t edition 1999
AII rights reserved. No part of this publication may be reproduced, stored in a retrieval
system or transmitted in any form or by any means, mechanical, photo-copying, recording,
or otherwise, without the prior written permission of the publisher,
Springer Science+Business Media, LLC.
Printed on acid-free paper.
This printing is a digital duplication of the original edition.
Contents
List of Figures ix
List of Tables xix
Preface xxi
Spreading Techniques, a Far-reaching Technology
P. W Baier, T. Weber and M. Weckerle
1.1 Introduction 1
1.2 Benefits of Spreading 4
1.3 Information Transmission Systems 6
1.4 Channel Identification Systems 9
1.5 Time and Frequency Estimation Systems 11
1.6 Application Examples 12
1.7 Promising Fields of Further Research 20
1.8 Conclusions 21
References 21
2
A Linear Model for COMA Signals Received with Multiple Antennas over 23
Multipath Fading Channels
Lars K. Rasmussen, Paul D. Alexander and Teng 1. Lim
2.1 Introduction 24
2.2 COMA Uplink System Model 25
2.3 Discrete-Time Baseband Uplink Model 27
2.4 Multiple-Antenna 45
2.5 Discussion 49
2.6 Concluding Remarks 53
References 55
3
Antenna Arrays for Cellular COMA Systems 59
P.M. Grant, 1.S. Thompson and B. Mulgrew
vi CDMA TECHNIQUES FOR THIRD GENERATION MOBILE SYSTEMS
3.1 Introduction 59
3.2 Background 59
3.3 Direct-Sequence CDMA 60
3.4 Motivations for Using Antenna Arrays 62
3.5 Channel Modelling Considerations 63
3.6 Receiver Algorithms 68
3.7 Uplink Simulation Work 71
3.8 Capacity Improvement with CDMA Antenna Arrays 76
3.9 Downlink Techniques 76
3.10 Summary 78
References 79
4
Spatial Filtering and CDMA 83
Michiel P. Lotter, Pieter van Rooyen and Ryuji Kohno
4.1 Introduction 84
4.2 Smart Antenna Techniques 85
4.3 BER Performance Calculation 88
4.4 Optimum Antenna Spacing Criteria 95
4.5 Mobile Location Distribution 97
4.6 Results 100
4.7 Conclusions 107
References 109
5
Topics in CDMA Multiuser Signal Separation 111
Y. Bar-Ness
5.1 Introduction 111
5.2 Multiuser CDMA Signal Model 113
5.3 Multiuser Decorrelating Detector 117
5.4 Adaptive Multistage Receiver for Multiuser CDMA 128
5.5 Conclusion 140
References 141
6
LMMSE Receivers for DS-CDMA Systems in Frequency-Selective Fading 145
Channels
Matti Latva-aho
6.1 Introduction 146
6.2 System Model 147
6.3 LMMSE Receivers in Fading Channels 148
6.4 Bit Error Probability Analysis for the Precombining LMMSE Receiver in
Fading Channels 150
6.5 Adaptive Implementations of the Precombining LMMSE Receivers 152
6.6 Delay Acquisition in the Precombining LMMSE Receiver 157
6.7 Delay Tracking in the Precombining LMMSE Receivers 160
6.8 Residual Blind Interference Suppression in PIC Receivers 162
6.9 Numerical Examples 164
6.10 Summary 174
References 176
Contents vii
7
Detection Strategies and Cancellation Schemes in a MC-CDMA System 185
Frans Kleer, Shin Hara and Ramjee Prasad
7.1 Introduction 185
7.2 MC/CDMA: System Description 187
7.3 Multiuser Interference in COMA Systems 190
7.4 Synchronisation in a MC/CDMA System 190
7.5 Detection Strategies for MC-CDMA Systems 195
7.6 Diversity Combining Techniques 199
7.7 Simulations 201
7.8 Results 205
7.9 Conclusions and Recommendations 207
References 209
8
Coding vs. Spreading over Block Fading Channels 217
Ezio Biglieri, Giuseppe Caire, and Giorgio Taricco
8.1 Introduction 217
8.2 System model 219
8.3 System capacity versus outage probability 222
8.4 Receiver design and mutual information 223
8.5 Numerical results 228
8.6 Conclusions 233
References 237
9
Turbo-Codes for future mobile radio applications 239
Peter lung, Jiirg Plechinger and Markus Doetsch
9.1 Introduction 239
9.2 Code concatenation 241
9.3 Iterative Turbo-Code decoding 244
9.4 Designing rate compatible punctured Turbo-Codes 246
9.5 Decoding complexity 248
9.6 Performance results 249
References 256
10
Software Radio Receivers 257
Tim Hentschel and Gerhard Fettweis
10.1 Introduction 257
10.2 Software Radio Concept 258
10.3 Investigation of Critical Functionalities 264
10.4 Summary 280
References 282
11
Blind Space-time Receivers for COMA Communications 285
David Gesbert, Boon Chong Ng and Arogyaswami l. Paulraj
11.1 Introduction 285
11.2 Space-time Signal Models 287
11.3 Single-user Receivers 289
Vlll CDMA TECHNIQUES FOR THIRD GENERATION MOBILE SYSTEMS
11.3 Single-user Receivers 289
11.4 Multi-user Receivers 291
11.5 MMSE Receiver Estimation 294
11.6 Summary 299
References 299
Index 303
List of Figu res
1.1 Basic system structure 2
1.2 Information transmission 2
1.3 Channel identification 3
1.4 Time and frequency estimation 3
1.5 Two different modes of spreading 4
1.6 Benefits of temporal spreading 5
1.7 Benefits of spectral spreading 6
1.8 Bandwidth luxury by FEC coding 7
1.9 Bandwidth luxury by broadband carrier 8
1.10 Decrease of required normalized SNR with increasing band-
width lUxury B / Bmin 10
1.11 Classification of channel identification systems 10
1.12 Temporal spreading 12
1.13 Thermal flow metering system 13
1.14 High resolution impulse compression radar 15
1.15 Cellular interference function f (r) (downlink) 17
1.16 Available Eb/ No with single user detection 18
1.17 Available Eb / No with multiuser detection 18
1.18 Required and available Eb / No with single user detection 19
1.19 Required and available Eb / No with multiuser detection 20
2.1 Block diagram of the mobile transmitter for user k. 25
2.2 Block diagram of the base station receiver. 26
2.3 Block diagram of the base station front-end. 26
2.4 Block diagram of the base station despreading unit for each user. 27
2.5 Examples of binary spreading sequences. From the top we
have S1 (0). S2 (0) and S1 (1). Chips 81 (3). 82 (4) and 81 (14) are
specifically labelled. 28
x CDMA TECHNIQUES FOR THIRD GENERATION MOBILE SYSTEMS
2.6 The filter impulse responses, autocorrelation functions and power
spectra for a square pulse and a raised cosine pulse with a roll-off
factor of 0.5 .. 29
2.7 Examples of zero padded and pulse shape filtered spreading
sequences, Xl (1), X2 (1) and Xl (2). 30
2.8 Discrete-time model of the uplink communication of a syn-
chronous CDMA system without channel distortions. 31
2.9 The fundamental structure of the matrix S for a synchronous
= = = = =
system with K 3, L 2, N 4, Q 2 and P 4. The
entries representing Sk (i) are indicated with dots, while all other
entries are zero. 32
2.10 Equivalent matched filters for user k. The top diagram corre-
sponds to the practical approach of one receiver filter while the
bottom diagram depicts the approach adopted in the model. 33
2.11 Discrete-time model of the uplink communication of a syn-
chronous CDMA system over a mobile radio channel. 34
2.12 Diagram of the tapped-delay line filtering of Xk (i) with Ck (i). 36
2.13 Discrete-time model of the uplink communication of an asyn-
chronous CDMA system over a mobile radio channel. 37
2.14 Fundamental structure of the matrix S for asynchronous CDMA
= = = = = =
with K 3, L 2, N 4, Q 2, P 4 and 71 0,
= =
72 4Ts and 73 5Ts. 38
2.15 An example of the transmitter and receiver mismatched wave-
forms for a maximum timing error of Ts/2 caused by off-sets
between the receiver clock and the transmitter clock. 39
2.16 The fundamental structure of the matrix S for multipath CDMA
= = = = = =
with K 3, L 2, N 4, Q 2, P 4, M 2
and M = 5Ts. The delays for the three users are (0,5Ts),
(3Ts,4Ts) and (4Ts, 9Ts), respectively. 42
2.17 Example of the resolution of paths in a multipath channel using a
sliding correlator energy detector based on a square pulse shape
and a raised cosine pulse shape, respectively. The actual channel
is included for reference. 43
2.18 Example of the severe attenuation due to a destructive combi-
nation of multipath delays, coefficients and spreading sequence.
The composite signal is practically annihilated. 44
2.19 Illustration of the transmitted signal for one user arriving at B
antennas at the receiver over B different multipath channels. 45
2.20 An illustration of the ULA with the direction of arrival () indicated. 46
2.21 Example of the resulting modulating waveform for user k with
two antenna elements in aULA. 48
2.22 Block diagram of the base station multiuser detection unit. The
numbers in parentheses indicate the number of signals passed
between blocks in one symbol interval. 49
LIST OF FIGURES xi
2.23 The fundamental structure of R for the multipath case in Fig.
2.16 where K = 3 and L = 6. The circles on the diagonal
represent the autocorrelations. The remaining dots represent
non-zero cross correlations. The band-diagonal structure is obvious. 50
2.24 Interference power versus desired signal power as a function of
the number of active users. 51
2.25 The fundamental structure of a powerful iterative receiver for
joint detection and decoding. 54
3.1 (a) Direct sequence modulation of a data sequence by a PN
code, (b) A typical autocorrelation function for a PN code, (c)
A typical cross-correlation function for two different users' PN codes. 61
3.2 Typical multipath profiles, drawn from the COST-207 report
[19], for (a) rural area, (b) typical urban area, (c) bad urban area
and (d) hilly terrain. 65
3.3 The space-time receiver structure for one user, operating with a
uniform linear array in a single 120° sector. 67
3.4 The beam patterns for the fixed beam, channel estimation and
PC-MMSE equaliser techniques, for a two users received at an
M = 4 element array. The bearings of the desired user's two
multipath components are shown as vertical lines. 71
3.5 The achieved SINR gain for the fixed beam (best and worst
beam sets), bearing estimation and channel estimation algo
rithms, plotted against the angular width Do. The array size
= =
M 8 and the algorithms estimate the channel from N 50
symbols. 72
3.6 The output SINR vs number of users plotted for the channel
estimation and PC-MMSE equaliser methods. Two different
=
scenarios are considered: (a) W 8 and background noise
=
- 20 dB and (b) W 64 and and background noise -10 dB. 73
3.7 The convergence performance of the PC method, plotted as
output SINR vs the number of averaged symbols (snapshots)
=
N. Results are shown for (a) array size M 4 and maximum
SINRs of 0,5 and 10 dB (b) maximum SINR of 5dB and array
sizeM=2,4,8or16. 74
3.8 The output SINR convergence performance of the PC method
with an M = 8 element array and angular widths of 0°, 20° and 60° 74
3.9 The output SINR plotted against number of averaged symbols
(snapshots) N for a scenario with array size M = 4. The
noise variance 0'2 is set to achieve an SINR ignoring CDMA
interference of (a) 10 dB with processing gain W = 64 and
10 users; (b) 20 dB with processing gain W = 8 and 5 users.
The maximum SINR and matched filter bounds are shown as
horizontal lines. 75
