PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS

Transcription

1 PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS

2 PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS By DON TORRIERI Springer

3 ebook ISBN: Print ISBN: Springer Science + Business Media, Inc. Print 2005 Springer Science + Business Media, Inc. Boston All rights reserved No part of this ebook may be reproduced or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without written consent from the Publisher Created in the United States of America Visit Springer's ebookstore at: and the Springer Global Website Online at:

4 To My Family

5 Contents Preface 1 Channel Codes 1.1 Block Codes Error Probabilities for Hard-Decision Decoding Error Probabilities for Soft-Decision Decoding Code Metrics for Orthogonal Signals Metrics and Error Probabilities for MFSK Symbols Chernoff Bound 1.2 Convolutional Codes and Trellis Codes Trellis-Coded Modulation 1.3 Interleaving 1.4 Concatenated and Turbo Codes Classical Concatenated Codes Turbo Codes 1.5 Problems 1.6 References xi Direct-Sequence Systems Definitions and Concepts Spreading Sequences and Waveforms Random Binary Sequence Shift-Register Sequences Periodic Autocorrelations Polynomials over the Binary Field Long Nonlinear Sequences Systems with PSK Modulation Tone Interference at Carrier Frequency General Tone Interference Gaussian Interference Quaternary Systems Pulsed Interference Despreading with Matched Filters 100 Noncoherent Systems Multipath-Resistant Coherent System

6 viii CONTENTS 2.7 Rejection of Narrowband Interference 113 Time-Domain Adaptive Filtering Transform-Domain Processing Nonlinear Filtering Adaptive ACM filter Problems References Frequency-Hopping Systems Concepts and Characteristics Modulations MFSK Soft-Decision Decoding Narrowband Jamming Signals Other Modulations Hybrid Systems Codes for Partial-Band Interference Reed-Solomon Codes Trellis-Coded Modulation Turbo Codes Frequency Synthesizers Direct Frequency Synthesizer Digital Frequency Synthesizer Indirect Frequency Synthesizers Problems References Code Synchronization Acquisition of Spreading Sequences 181 Matched-Filter Acquisition Serial-Search Acquisition Uniform Search with Uniform Distribution Consecutive-Count Double-Dwell System Single-Dwell and Matched-Filter Systems Up-Down Double-Dwell System Penalty Time Other Search Strategies Density Function of the Acquisition Time Alternative Analysis Acquisition Correlator Code Tracking Frequency-Hopping Patterns Matched-Filter Acquisition Serial-Search Acquisition Tracking System Problems 228

7 CONTENTS ix 4.7 References Fading of Wireless Communications Path Loss, Shadowing, and Fading Time-Selective Fading Fading Rate and Fade Duration Spatial Diversity and Fading Frequency-Selective Fading Channel Impulse Response Diversity for Fading Channels Optimal Array Maximal-Ratio Combining Bit Error Probabilities for Coherent Binary Modulations Equal-Gain Combining Selection Diversity Rake Receiver Error-Control Codes Diversity and Spread Spectrum Problems References Code-Division Multiple Access Spreading Sequences for DS/CDMA Orthogonal Sequences Sequences with Small Cross-Correlations Symbol Error Probability Complex-Valued Quaternary Sequences Systems with Random Spreading Sequences Direct-Sequence Systems with PSK Quadriphase Direct-Sequence Systems Wideband Direct-Sequence Systems Multicarrier Direct-Sequence System Single-Carrier Direct-Sequence System Multicarrier DS/CDMA System Cellular Networks and Power Control Intercell Interference of Uplink Outage Analysis Local-Mean Power Control Bit-Error-Probability Analysis Impact of Doppler Spread on Power-Control Accuracy Downlink Power Control and Outage Multiuser Detectors Optimum Detectors Decorrelating detector Minimum-Mean-Square-Error Detector Interference Cancellers

8 x CONTENTS 6.6 Frequency-Hopping Multiple Access 362 Asynchronous FH/CDMA Networks Mobile Peer-to-Peer and Cellular Networks Peer-to-Peer Networks Cellular Networks Problems References Detection of Spread-Spectrum Signals Detection of Direct-Sequence Signals 387 Ideal Detection Radiometer Detection of Frequency-Hopping Signals Ideal Detection Wideband Radiometer Channelized Radiometer Problems References 408 Appendix A Inequalities 409 A.1 Jensen s Inequality 409 A.2 Chebyshev s Inequality 410 Appendix B Adaptive Filters 413 Appendix C Signal Characteristics 417 C.1 Bandpass Signals 417 C.2 Stationary Stochastic Processes Power Spectral Densities of Communication Signals C.3 Sampling Theorems 424 C.4 Direct-Conversion Receiver 426 Appendix D Probability Distributions 431 D.1 Chi-Square Distribution 431 D.2 D.3 D.4 D.5 Central Chi-Square Distribution Rice Distribution Rayleigh Distribution Exponentially Distributed Random Variables Index 439

9 Preface The goal of this book is to provide a concise but lucid explanation and derivation of the fundamentals of spread-spectrum communication systems. Although spread-spectrum communication is a staple topic in textbooks on digital communication, its treatment is usually cursory, and the subject warrants a more intensive exposition. Originally adopted in military networks as a means of ensuring secure communication when confronted with the threats of jamming and interception, spread-spectrum systems are now the core of commercial applications such as mobile cellular and satellite communication. The level of presentation in this book is suitable for graduate students with a prior graduatelevel course in digital communication and for practicing engineers with a solid background in the theory of digital communication. As the title indicates, this book stresses principles rather than specific current or planned systems, which are described in many other books. Although the exposition emphasizes theoretical principles, the choice of specific topics is tempered by my judgment of their practical significance and interest to both researchers and system designers. Throughout the book, learning is facilitated by many new or streamlined derivations of the classical theory. Problems at the end of each chapter are intended to assist readers in consolidating their knowledge and to provide practice in analytical techniques. The book is largely self-contained mathematically because of the four appendices, which give detailed derivations of mathematical results used in the main text. In writing this book, I have relied heavily on notes and documents prepared and the perspectives gained during my work at the US Army Research Laboratory. Many colleagues contributed indirectly to this effort. I am grateful to my wife, Nancy, who provided me not only with her usual unwavering support but also with extensive editorial assistance.