Introduction to Spread-Spectrum Communications By Roger L. Peterson (Motorola), Rodger E. Ziemer (University of Co. at Colorado Springs), and David E. Borth (Motorola) Prentice Hall, 1995 (Navtech order #2430) Table of Contents Preface...XIII Acknowledgments... XVII Prologue... 1 Chapter 1 Basic Digital Communications Concepts... 6 1.1 Introduction... 6 1.2 Detection of binary signals in additive white Gaussian noise... 6 1.2.1 Coherent modulation schemes... 6 1.2.2 Noncoherent modulation schemes... 12 1.3 Signal detection in geometric terms... 15 1.3.1 Gram-Schmidt procedure... 15 1.3.2 Geometric view of signal detection... 16 1.3.3 M-ary phase shift keying... 18 1.3.4 Coherent M-ary frequency shift keying... 20 1.3.5 M-ary quadrature amplitude shift keying... 21 1.3.6 Differentially coherent phase-shift keying... 22 1.3.7 Noncoherent M-ary FSK... 23 1.3.8 Hybrid modulation schemes... 23 1.4 Comparison of modulation schemes... 31 1.4.1 Bandwidth efficiency... 31 1.4.2 Power efficiency... 32 1.5 Signaling through fading channels... 33 1.6 Summary... 41 References... 41 Problems... 43 Chapter 2: Introduction to Spread Spectrum Systems... 47 2.1 Introduction... 47 2.2 Two communications problems... 48 2.2.1 Pulse-noise jamming... 48 2.2.2 Low probability of detection... 50 2.3 Direct sequence spread spectrum... 64 2.4 Frequency hop spread spectrum... 68 2.4.1 Coherent slow frequency hop spread spectrum... 68 2.4.2 Noncoherent slow frequency hop spread spectrum... 73 2.4.3 Noncoherent fast frequency hop spread spectrum... 75 2.5 Hybrid direct sequence/frequency hop spread spectrum... 75 2.6 Complex envelope representation of spread spectrum systems... 78 2.7 Summary... 83 References... 83 Problems... 84 Chapter 3: Binary Shift Register Sequences for Spread Spectrum Systems... 89
3.1 Introduction... 89 3.2 Definitions, mathematical background and sequence generator fundamentals... 90 3.2.1 Definitions... 90 3.2.2 Finite field arithmetic... 91 3.2.3 Sequence generator fundamentals... 99 3.2.4 State machine representation of shift register generators...109 3.3 Maximal length sequences...113 3.3.1 Properties of m-sequences...113 3.3.2 Power spectrum of m-sequences...115 3.3.3 Tables of polynomials yielding m-sequences...117 3.3.4 Partial autocorrelation properties of m-sequences...121 3.3.5 Power spectrum of c(t)c(t+h)...125 3.3.6 Generation of specific delays of an m-sequence...128 3.4 Gold codes...135 3.5 Nonlinear code generators...138 3.6 Summary...142 References...143 Problems...144 Chapter 4: Code Tracking Loops...149 4.1 Introduction...149 4.2 Optimum tracking of wideband signals...150 4.3 Baseband delay lock tracking loop...153 4.4 Noncoherent delay lock tracking loop...164 4.5 Tau-dither noncoherent tracking loop...179 4.6 Double-dither noncoherent tracking loop...189 4.7 Noncoherent delay lock tracking loop with arbitrary data and Spreading modulation...192 4.8 Code tracking loops for frequency hop systems...201 4.9 Summary...213 References...215 Problems...216 Chapter 5: Initial Synchronization of the Receiver Spreading Code...221 5.1 Introduction...221 5.2 Problem definition and the optimum synchronizer...223 5.3 Serial search synchronization techniques...225 5.3.1 Calculation of the mean and variance of synchronization time...225 5.3.2 Modified sweep strategies...230 5.3.3 Continuous linear sweep of the uncertainty region...233 5.3.4 Detection of a signal in additive white Gaussian noise...240 5.4 Generalized analysis of average synchronization time...283 5.5 Synchronization using a matched filter...291 5.6 Synchronization by estimating the received spreading code...301 5.7 Tracking loop pull-in...303 5.8 Summary...308 References...311 Problems...315 Chapter 6: Performance of Spread Spectrum Systems in Jamming Environments...319 6.1 Introduction...319
6.2 Spread spectrum communication system model...320 6.3 Performance of spread spectrum systems without coding...326 6.3.1 Performance in AWGN or barrage noise jamming...327 6.3.2 Performance in partial band jamming...337 6.3.3 Performance in pulsed noise jamming...350 6.3.4 Performance in single tone jamming...354 6.3.5 Performance in multiple tone jamming...368 6.3.6 Conclusions...373 6.4 Summary...374 References...375 Problems...378 Chapter 7: Performance of Spread Spectrum Systems with Forward Error Correction...381 7.1 Introduction...381 7.2 Elementary block coding concepts...382 7.2.1 Basic concepts...403 7.2.2 Optimum decoding rule...385 7.2.3 Calculation of error probability...391 7.3 Elementary convolutional coding concepts...403 7.3.1 Basic concepts...403 7.3.2 Definition of a convolutional code...404 7.3.3 Decoding convolutional codes...408 7.3.4 Viterbi algorithm...413 7.3.5 Decoding and bit error probability...427 7.3.6 Other topics 429 7.4 Results for specific error correction codes...431 7.4.1 BCH codes...431 7.4.2 Reed-Solomon codes...433 7.4.3 Maximum free distance convolutional codes...434 7.4.4 Repeat coding for the hard decision FH/MFSK channel...435 7.5 Interleaving...447 7.6 Coding bounds...449 7.6.1 Error probability bounds using the channel parameter D...449 7.6.2 Computational cutoff rate Ro...453 7.7 Summary...454 References...455 Problems...458 Chapter 8: Introduction to Fading Channels...460 8.1 Introduction...460 8.2 Statistical model of fading...460 8.2.1 General fading channel model...462 8.2.2 WSSUS fading channels...467 8.2.3 Doubly spread channels...468 8.2.4 Time selective fading channels...471 8.2.5 Frequency selective fading channels...475 8.2.6 Nondispersive fading channels...480 8.3 Characterization of the mobile radio channel...482 8.3.1 time selective fading...483 8.3.2 Frequency selective fading...486 8.3.3 Mobile radio path loss...488
8.3.4 Shadowing...490 8.3.5 Coverage reliability...491 8.4 Requirement for diversity in fading channels...493 8.4.1 Diversity approaches...497 8.4.2 Diversity combining methods...500 8.4.3 Performance of maximal ratio combining...502 8.4.4 Other diversity combining methods...506 8.4.5 The Rake receiver...507 8.4.6 Summary: The benefits of diversity...512 8.5 Summary...513 References...513 Problems...517 Chapter 9: Code Division Multiple Access Digital Cellular Systems...520 9.1 Introduction...520 9.2 Cellular radio concept...520 9.2.1 Fundamentals of cellular radio systems...521 9.2.2 Co-channel interference protection prediction...526 9.2.3 Cellular concept revisited...528 9.3 CDMA digital cellular systems...530 9.3.1 General aspects of CDMA digital cellular systems...535 9.3.2 Special aspects of CDMA digital cellular systems...535 9.4 Specific examples of CDMA digital cellular systems...535 9.4.1 North American DS-CDM digital cellular system (IS-95)...536 9.4.2 Cooper and Nettleton DPSK-FHMA system...550 9.4.3 Bell Labs multilevel FSK frequency hop system...553 9.4.4 SFH900 system...559 9.4.5 GSM-SFH digital cellular system...561 9.4.6 Hybrid SFH TDMA/CDMA system for PCS applications...566 9.5 Summary...572 References...574 Problems...581 Chapter 10: Low Probability-of-Intercept Methods...584 10.1 Introduction...584 10.2 Nature of covert communications...584 10.3 Energy detection in AWGN...586 10.4 Optimum intercept receivers for spread spectrum signals...591 10.4.1 Introduction...591 10.4.2 Optimum intercept receiver for direct sequence spread spectrum...591 10.4.3 Intercept receivers for frequency hop spread spectrum...599 10.5 The OR/BMWD: Approximately optimum spread spectrum signal detector...602 10.6 Estimation of spread spectrum signal parameters...605 References...611 Problems...613 Appendix A: Summary of Phase-Locked Theory...615 A-1 Introduction...615 A-2 Phase-locked loop models and characteristics of operation...615 A-2.1 Synchronized mode: linear operation...615 A-2.2 Effects of noise...619
A-2.3 Phase-locked loop tracking of oscillators with phase noise...625 A-2.4 Phase jitter plus noise effects...625 A-2.5 Transient response...628 A-2.6 Phase-locked loop acquisition...631 A-2.7 Effects of transport delay...635 A-3 Frequency Synthesis...636 A-3.1 Introduction...636 A-3.2 Digital synthesizer...636 A-3.3 Direct synthesis...638 A-3.4 Phase-locked frequency synthesizers...641 References...643 Appendix B: Gaussian Probability Function...644 Reference...645 Appendix C: Power Spectral Densities for sequences of Random Binary Digits and Random Tones...646 Reference...650 Appendix D: Calculation of the Power Spectrum of the Product of Two M-Sequences...651 Reference...659 Appendix E: Evaluation of Phase Discriminator Output Autocorrelation Functions and Power Spectra...660 E-1 Noncoherent delay lock tacking loop...660 E-2 Tau-dither noncoherent tracking loop...665 References...671 Appendix F: Numerical Approximations for the Chi-Squared Probability Distribution and Marcum s Q-Function...672 F-1 Introduction...672 F-2 Computation of the (Central) Chi-squared distribution...672 F-3 Generalized Marcum s Q-Function...676 F-4 Noncentral Chi-squared distribution...678 References...681 Appendix G: Mathematical Tables...682 Index...689