Spread Spectrum Systems for GNSS and Wireless Communications

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1 Spread Spectrum Systems for GNSS and Wireless Communications Jack K. Holmes ARTECH H O U SE BOSTON LONDON artechhouse.com

Contents Chapter 1 An Introduction to Spread Spectrum Systems 1 1.0 Introduction 1 1.1 A Very Brief History of Spread Spectrum Communications 2 1.

2 Contents Chapter 1 An Introduction to Spread Spectrum Systems Introduction A Very Brief History of Spread Spectrum Communications A Digital Spread Spectrum Communication Systems Model Narrowband Signals Narrowband Process Via the Complex Envelope Narrowband Signals Through Narrowband Systems Complex Envelope Characterization for Direct Sequence and Frequency-Hopping Signals Direct Sequence Spread Spectrum Systems Direct Sequence Spreading with Binary Phase Shift Keying (BPSK) Quadriphase Direct Sequence Spread Spectrum Systems Minimum Shift Keying (MSK) Frequency-Hopped Spread Spectrum Systems Noncoherent Slow Frequency-Hopped Systems with MFSK Data Modulation Noncoherent Fast Frequency-Hopped Systems with MFSK Data Modulation Noncoherent Slow Frequency-Hopped Systems with DPSK Data Modulation Noncoherent Slow Frequency-Hopped Signals with BPSK Data Modulation Hybrid Spread Spectrum Systems Hybrid DS with Slow Frequency Hopping with BPSK Data Hybrid OQPSK DS with SFH with BPSK Data Time Hopping Spread Spectrum Signals An Introduction to OFDM OFDM Communication System Implemented Via the FFT OFDM Intersymbol Interference Reduction Techniques OFDM Power Spectral Density An Introduction to Ultrawideband Communications A Brief Early History of UWB Communications Description of UWB Signals Regulatory Constraints and Spectral Masks for Various UWB Applications Impact of the Transmit Antenna on the Transmitted Signal The Advantages and the Disadvantages of Impulse Versus Multicarrier UWB Advantages of UWB Systems Applications of UWB The Near-Far Problem Low Probability oflnterception Summary 58 References 58 Problems 60 vn

VIII Spread Spectrum Systems for GNSS and Wireless Communications Chapter 2 Binary Shift Register Codes for Spread Spectrum Systems 63 2.0 Introduction 63 2.1 Finite Field Arithmetic 63 2.1.1 Polynomial Arithmetic 65 2.

3 VIII Spread Spectrum Systems for GNSS and Wireless Communications Chapter 2 Binary Shift Register Codes for Spread Spectrum Systems Introduction Finite Field Arithmetic Polynomial Arithmetic Shift Register Sequences Equivalence of the Fibonacci and Galois Formsofa Linear SRG Mathematical Characterization of SRGs The Shift Register Matrix The Characteristic Equation and Characteristic Polynomial The Generating Function The Correlation Function of Sequences Periodic Correlation Functions for Sequences Aperiodic Correlation Functions for Sequences Codes for Spread Spectrum Multiple Access Applications Binary Maximal Length Sequences Gold Codes Gold-Like Sequences and Dual BCH Sequences Kasami Sequences Bent Sequences Comparisonof CDMA Code Performance Sequences with Good Aperiodic Correlation Barker and Williard Sequences Neuman-Hofman Sequences Partial Period Correlation for m-sequences Frequency-Hopping Multiple Access Code Generators Summary 114 References 114 Problems 116 Chapter 3 Jamming Performance of Uncoded Spread Spectrum Systems Introduction Jammer Types Bit Error Rate Performance in Broadband Noise Jamming DS/PSK in Broadband Noise Jamming SFH/DPSK in Broadband Noise Jamming SFH/PSK in Broadband Noise Jamming SFH/MFSK in Broadband Noise Jamming FFH/BFSK in Broadband Noise Jamming Hybrid DS-SFH SS Modulation in Broadband Noise Jamming BER Performance in Partial Band Noise Jamming DS/PSK in Partial Band Noise Jamming SFH/DPSK Systems in Partial Band Noise Jamming SFH/PSK BER in Partial Band Noise Jamming SFH/MFSK in Partial Band Noise Jamming FFH/MFSK in Partial Band Noise Jamming Hybrid DS-SFH/MFSK in Partial Band Noise Jamming Hybrid DS-SFH/DPSK in Partial Band Noise Jamming Bit Error Rate Performance in Pulsed Jamming Bit Error Rate Performance for DS/PSK in Pulsed Jamming Performance of SFH/MFSK in Pulsed Jamming Performance of SFH/DPSK in Pulsed Jamming Performance of Hybrid DS-SFH/MFSK in Pulsed Jamming 160

Contents ix 3.4.5 Performance of Hybrid DS-SFH/DPSK in Pulsed Jamming 161 3.5 Bit Error Rate Performance in Tone Jamming 161 3.5.1 Bit Error Rate Performance for DS(BPSK)/BPSK in Tone Jamming 161 3.5.2 Bit Error Rate Performance for DS(QPSK)/BPSK in Tone Jamming 165 3.

4 Contents ix Performance of Hybrid DS-SFH/DPSK in Pulsed Jamming Bit Error Rate Performance in Tone Jamming Bit Error Rate Performance for DS(BPSK)/BPSK in Tone Jamming Bit Error Rate Performance for DS(QPSK)/BPSK in Tone Jamming Bit Error Rate Performance for DS(MSK)/BPSK in Tone Jamming Multitone Jamming Bit Error Rate Performance Multitone Jamming Bit Error Rate Performance for SFH/MSK Multitone Jamming Bit Error Rate Performance for SFH/DPSK Degradation Due to Interference or Jamming in DS Systems Equivalent Noise Spectral Density for DS(BPSK)/BPSK Systems Carrier to Equivalent Noise Spectral Density Ratio for DS(BPSK)/BPSK Equivalent Noise Spectral Density Degradation for DS(BPSK)/BPSK Systems Degradation to NRZ Signals Due to Narrowband Jammers for DS(BPSK)/BPSK Signals Summary 186 References 186 Problems 187 Chapter 4 Jamming Performance of Coded Spread Spectrum Systems Introduction Interleaver Structures for Coded Systems Block Periodic Interleaving Convolutional Interleaving Linear Block Coding Linear Block Coding Concepts Rule for Optimum Decoding with No Jammer Side Information Rule for Optimum Decoding with Jammer Side Information Computationofthe Block Coded Word and Bit Error Rate Convolutional Codes Convolutional Code Encoder Characterization The Transfer Function of a Convolutional Code and the Free Distance Decoding of Convolutional Codes The Viterbi Algorithm Error Probabilities for Viterbi Decoding of Convolutional Codes Sequential Decoding of Convolutional Codes Threshold Decoding of Convolutional Codes Nonbinary Convolutional Codes Iteratively Decoded Codes Turbo Codes A Serial Concatenated Convolutional Code Serial Concatenated Block Codes Parallel Concatenated Block Codes Low-Density Parity Check Codes Selected Results for Some Error Correction Codes Böse, Chaudhuri, and Hocquenghem Codes Reed-Solomon Codes Convolutional Codes with Maximum Free Distance 257

x Spread Spectrum Systems for GNSS and Wireless Communications 4.5.4 Hard- and Soft-Decision FFH/MFSK with Repeat Coding BER Performance 259 4.

5 x Spread Spectrum Systems for GNSS and Wireless Communications Hard- and Soft-Decision FFH/MFSK with Repeat Coding BER Performance Shannon's Capacity Theorem, the Channel Coding Theorem, and BW Efficiency Shannon's Capacity Theorem Channel Coding Theorem Bandwidth Efficiency Application oferror Control Coding Summary 269 References 269 Selected Bibliography 272 Problems 272 Chapter 5 Carrier Tracking Loops and Frequency Synthesizers Introduction Tracking of Residual Carrier Signals PLL for Tracking a Residual Carrier Component The Likelihood Function for Phase Estimation The Maximum-Likelihood Estimation of Carrier Phase Long Loops and Short Loops The Stochastic Differential Equationof Operation The Linear Model of the PLL with Noise The Various Loop Filter Types Transient Response of a Second-Order Loop Steady State Tracking Error When the Phase Error Is Small The Variance of the Linearized PLL Phase Error Due to Thermal Noise Frequency Response of the Active Filter Second-Order PLL Phase Noise Effects of the Total Phase Error in the PLL Nonlinear PLL Results Frequency Synthesizers Digital Frequency Synthesis Direct Frequency Synthesis Indirect Frequency Synthesis Indirect Frequency Synthesis Transfer Functions Tracking of BPSK Signals Tracking a BPSK Signal with a Squaring Loop Tracking a BPSK Signal with an Integrate-and-Dump Costas Loop Tracking a BPSK Signal with a Passive Arm Filter Costas Loop Steady State Tracking Error for the Costas and Squaring Loops Costas Loop with Hard-Limited In-Phase Arm Processing Improved Frequency Acquisition of a Passive Filter Costas Loop Lock Detectors for Costas and Squaring Loops False Lock in Costas Loops Decision-Directed Feedback Loops Multiphase Tracking Loops The JV-th Power Loop The N-Phase Costas Loop Demod-Remod Quadriphase Tracking Loop Modified Four-Phase Costas Loop-SQPSK Modulation Frequency Locked Loops 341

Contents XI 5.6.1 The Cross Product FLL 341 5.7 Summary 342 References 343 Problems 345 Chapter 6 Code Acquisition in Direct Sequence Receivers 349 6.0 Introduction 349 6.

6 Contents XI The Cross Product FLL Summary 342 References 343 Problems 345 Chapter 6 Code Acquisition in Direct Sequence Receivers Introduction The Acquisition Problem Active Search Acquisition (Sliding Correlator) Mean Acquisition Time Model for an Active Search System Analysis of the Active Search System Single Dwell Mean Acquisition Time Formula with Doppler Mean Acquisition Time for the Double Dwell Time Search Active Acquisition System Structures Used for Acquisition for BPSK, QPSK, OQPSK, and MSK Acquisition Probability Versus Time for Active Correlation Parallel Methods of Active Code Acquisition Active Search Mean Acquisition Time with Parallel Processing Active Code Search Utilizing the FFT Signal Modeling for BPSK Code Acquisition Utilizing the FFT Model for the Correlator Output Out of the FFT Evaluation of the FFT Enhanced Acquisition System Output Variance for an Arbitrary Gaussian Noise Process BPSK Code Modulation Evaluation of P D and P FA for Arbitrary Noise Gaussian Approximation of the Detection Probability for BPSK Losses Between Bins in a Zero Padded FFT The Frequency Search Range and Total Frequency Losses Using an FFT The Correlator Bins of the FFT Are Uncorrelated BPSK Code Modulation y in a Matched Spectral Jammer BPSK Code Modulation y in a Narrowband Jammer Balanced QPSK and Balanced OQPSK Acquisition Performance A Gaussian Approximation for P D for Balanced QPSK and Balanced OQPSK An Optimum Sweep Search Technique for Active Acquisition Sequential Detection Sequential Probability Ratio Test Sequential Detection for DS Acquisition with BPSK Data Modulation A Sequential Detection Implementation Acquisition Time ofa Sequential Detector The Tong Detector Transform Methods Used in Code Acquisition Code Acquisition Using a Passive Matched Filter The Matched Filter Optimum Time of ArrivalEstimator Digital Passive Matched Filter Introduction DPMF Acquisition Model Digital Matched Filter Acquisition Time Model Signal Model for DPMF Noise Variance Equation for a Gaussian Random Process Model ofa Jammer 426

xii Spread Spectrum Systems for GNSS and Wireless Communications 6.9.8 Variance Evaluation of an MSJ 426 6.9.9 Correlation Signal Voltage Loss 427 6.9.10 Combining Coherent Segments of the DMF with the FFT 428 6.

7 xii Spread Spectrum Systems for GNSS and Wireless Communications Variance Evaluation of an MSJ Correlation Signal Voltage Loss Combining Coherent Segments of the DMF with the FFT Detection and False Alarm Probability Densities for the NRZ Code Case The Acquisition Probability Mean Acquisition Time Calculation Serial Active Search for Acquisition of FH/MFSK Signals Serial Active Search for Acquisition of FFH/MFSK Signals Detection and False Alarm Probabilities for FFH/MFSK Serial Active Search Detection and False Alarm Probabilities for SFH/MFSK Serial Active Search Acquisition Time Calculations for FFH/MFSK and SFH/MFSK Summary 451 References 452 Selected Bibliography 454 Problems 455 Appendix 6A Signal Flow Graphs and Discrete Time Invariant Markov Processes 458 Chapter 7 Direct Sequence Code-Tracking Loops Introduction Basis for the Early-Late Gate Code-Tracking Loop Maximum-Likelihood Estimate Formulation Maximum-Likelihood Estimate of the PN Code Timing Full-Time Code-Tracking Loops Baseband Early-Late Gate Code-Tracking Loop with NRZ Symbols Noncoherent Early-Late Gate I-Q Code-Tracking Loop Noncoherent Early-Late Gate RF Implemented Code-Tracking Loop Noncoherent I-Q Dot Product Code-Tracking Loop with Passive Arm Filters Noncoherent I-Q Dot Product Code-Tracking Loop with Active Arm Filters Early-Late Gate Noncoherent I-Q Code-Tracking with Filtering and Interference Signal Model for the Noncoherent I-Q Early-Late Gate Code- Tracking Loop with Channel Filtering Signal and Noise Terms in the Noncoherent I-Q Early-Late Gate Code Loop with Channel Filtering Signal Terms in the Noncoherent I-Q Early-Late Gate Code Loop with Channel Filtering Closed-Loop Operation of the Noncoherent I-Q Early-Late Gate Code Loop with Channel Filtering Noncoherent I-Q Early-Late Gate Code-Tracking Loop with Channel Filtering of N(t) at/= Noncoherent Early-Late Gate I-Q Code Loop Tracking Error Variance with Channel Filtering Noncoherent Early-Late Gate Code I-Q Tracking Error Variance with Thermal Noise and Without Channel Filtering 521

Contents Xlll 7.3.8 Noncoherent Early-Late Gate I-Q Code-Tracking Error Variance with Channel Filtering in White Gaussian Noise with NRZ Symbols 522 7.3.9 Noncoherent Early-Late Gate I-Q Code-Tracking Performance with Narrowband Gaussian Interference Plus White Gaussian Noise with NRZ Symbols and No Channel Filtering 523 7.

8 Contents Xlll Noncoherent Early-Late Gate I-Q Code-Tracking Error Variance with Channel Filtering in White Gaussian Noise with NRZ Symbols Noncoherent Early-Late Gate I-Q Code-Tracking Performance with Narrowband Gaussian Interference Plus White Gaussian Noise with NRZ Symbols and No Channel Filtering Time-Shared Noncoherent Code-Tracking Loops Performance of a Noncoherent RF Implemented Time Gated Early-Late Gate Bandpass Code-Tracking Loop Steady State Error of Code-Tracking Loops Without Noise First-Order Noncoherent I-Q Early-Late Gate Code-Tracking Loop Second-Order Ideal Noncoherent I-Q Early-Late Gate Code-Tracking Loop Early-Late Gate Noncoherent I-Q Code-Tracking Loop Pull-In Without Noise Multipath Effects Multipath Effects on Filtered Noncoherent Code-Tracking Loops Multipath Effects on Baseband Coherent I-Q Code-Tracking Loops The Multipath Error Plots Are the Same for Coherent and Noncoherent Code-Tracking Loops Mean Time to Lose Lock for a First-Order Early-Late Gate RF Code-Tracking Loop Model for the Analysis of the Mean Slip Time Performance of the Early-Late Gate Code-Tracking Loop with RF Implementation Mean Slip Time Comparison of Theory and Simulation for the Early-Late Gate Code-Tracking Loop with RF Implementation Wideband Jamming Effects on Tracking and Mean Time to Lose Lock for the Early-Late Gate Code-Tracking Loop with RF Implementation Cramer-Rao Bound on Code-Tracking Error Phase Rotation and Heterodyning for Receiver Use Heterodyning the Signal to Near Baseband Phase Rotation or Single Sideband Translation Pulsing and Blanking in a Baseband Early-Late Code-Tracking Loop Baseband Signal and Code Loop Model for a Baseband Early-Late Gate I-Q Code-Tracking Loop with Pulsing Füll Correlation in the Coherent Baseband I-Q Code-Tracking Loop When the Signal Is Pulsed Synchronous Blanking of the Noise When the Signal Is Pulsed Off Summary 577 References 577 Selected Bibliography 579 Problems 579 Appendix 7A Mean Time to Lose Lock for a First-Order Early-Late Gate Code- Tracking Loop with Either Bandpass Arm Filters or Baseband Arm Filters 582 Chapter 8 Tracking of Frequency-Hopped Signals Introduction Dataless Frequency-Hopped Time Tracking Loop Model Loop Model for the Frequency-Hopping Loop Without Data Evaluation of the Spectral Density of the Noise Terms Closed Loop Tracking Loop Performance Frequency-Hopping Tracking with BPSK and DPSK Data Modulation Summary 602 References 602

XIV Spread Spectrum Systems for GNSS and Wireless Communications Problem 602 Chapter 9 Multiple Access Methods for Digital Wireless Cellular Communications 603 9.0 Introduction 603 9.

9 XIV Spread Spectrum Systems for GNSS and Wireless Communications Problem 602 Chapter 9 Multiple Access Methods for Digital Wireless Cellular Communications Introduction Brief History of Cellular Systems Cellular Communications Cellular System Architecture Mobile Cells Mobile Clusters Frequency Reuse in a Cellular System Cell Splitting Handoff More on Cell Structure Assignment Strategies for Channelization Multiple Access Techniques for Wireless Communications A Brief Introduction to Multiple Access Frequency Division Multiple Access Time Division Multiple Access The EfficiencyofTDMA Systems TheNumber of Available Channels in atdma System Spread Spectrum Multiple Access Frequency-Hopped Multiple Access Code Division Multiple Access Hybrid Techniques for Spread Spectrum Signals Space Division Multiple Access The Capacityof Cellular CDMA ofa Single Cell Packet Radio Access Techniques ALOHA Channel The Slotted ALOHA Channel Carrier Sense Multiple Access Protocols Persistent CSMA Nonpersistent CSMA p-persistent CSMA Conceptual Comparison of the Multiple Access Methods Multiuser Detection Concepts The Matched Filter for CDMA Signals Conventional Single User Detector in the Synchronous Case Decorrelating Detector Minimum Mean Square Error Estimator Additional Types of Multiuser Detector Systems Successive Interference Cancellation Multistage Interference Cancellation Bit Error Rate Performance Estimates of the Detectors An Example of a CDMA System: cdma cdma2000 Layering Structure Overview Forward Link and Reverse Link Channels Overview Physical Layer of cdma Forward Link Physical Channels cdma2000 Reverse Physical Channels Data Services in cdma WCDMA WCDMA Radio Frequency Protocol Architecture WCDMA Channels 669

Contents xv 9.12.3 WCDMA Physical Layer 669 9.12.4 WCDMA Channel Coding 672 9.12.5 WCDMA Power Control 673 9.12.6 WCDMA Random Access 674 9.12.7 WCDMA Initial Cell Search 674 9.12.8 WCDMA Handover 674 9.

10 Contents xv WCDMA Physical Layer WCDMA Channel Coding WCDMA Power Control WCDMA Random Access WCDMA Initial Cell Search WCDMA Handover WCDMA Packet Data Services Summary 676 References 676 Problems 678 Chapter 10 An Introduction to Fading Channels Introduction An Introduction to Radio Propagation Outdoor Models for Large-Scale Effects Free Space Path Loss Model Received Signal Power and the Electric Field Strength Plane Earth Propagation Path Loss Model Egli's Path Loss Model Okumura-Hata Path Loss Model COST-231 Hata Path Loss Model ECC-33 Path Loss Model Microcell Propagation Models Large-Scale Effects for Indoor Models Log-Normal Path Loss Model for Indoors Floor Attenuation Factor Path Loss Model Small-Scale Effects Multipath Fading Rayleigh and Rician Fading Models Small-Scale Fading Types Multipath Time Delay Spread Fading Fading Effects of Multipath Doppler Spread Characterization of Wideband Channels Deterministic Models Stochastic Time-Variant Linear Channels The Wide-Sense Stationary Channels The Uncorrelated Scattering Channel The Wide-Sense Stationary Uncorrelated Scattering Channel The Effects of a Rayleigh Fading Channel on the Bit Error Rate The Effects of a Rayleigh Fading Channel on the BPSK Bit Error Rate The Effects of a Rayleigh Fading Channel on the DPSK Bit Error Rate The Effects of a Rayleigh Fading Channel on Noncoherent Orthogonal BFSK Bit Error Rate Nakagami Fading Channel Model Mitigation Methods for Multipath Effects Diversity for Multipath Improvement Combining Methods for Fading Mitigation Equalization for Multipath Improvement Baseband Transversal Symbol Rate Equalizer Baseband Adaptive Equalization Baseband Decision Feedback Equalizers Diversity Techniques for Multipath Improvement 732

xvi Spread Spectrum Systems for GNSS and Wireless Communications 10.9.1 Multipath Performance Improvement Via Diversity Techniques for Binary Channels 732 10.10 The RAKE Receiver 739 10.10.1 The Tapped Delay Line Channel Model for a Frequency Selective Slowly Fading Channel 739 10.

11 xvi Spread Spectrum Systems for GNSS and Wireless Communications Multipath Performance Improvement Via Diversity Techniques for Binary Channels The RAKE Receiver The Tapped Delay Line Channel Model for a Frequency Selective Slowly Fading Channel The RAKE Receiver Performance ofthe RAKE Receiver Binary Coded Chernoff BER Bounds for Fading Channels Chernoff Bound for Binary Linear Block Codes Coded Orthogonal FSK Signal Model for Fading Channels BER of Soft-Decision Decoding and FSK Modulation with Linear Binary Block Codes over Rayleigh Fading Channels BER of Hard-Decision Decoding and FSK Modulation with Linear Binary Block Codes over Rayleigh Fading Channels Chernoff Bounds for the BER of Convolutional Codes over Rayleigh Fading Channels with Soft and Hard Decisions and Binary FSK Modulation Smart Antenna Systems for Wireless Systems Smart Antenna Systems Adaptive Array Smart Antennas Adaptive Array Spatial Processing Forming Smart Antennas with Switched Beams MIMO Systems Summary 759 References 760 Problems 762 Chapter 11 Low Probability of Detection Systems Introduction Low Probability of Intercept (LPI) Covert Communications The LPI Scenario Brief Signal Propagation Summary An Introduction to Radiometrie Detectors The Radiometer Limitations ofthe Radiometer Performance Results Low-Pass Filter Radiometer The Correlation Radiometer Relationship ofthe Output SNR and the Deflection The Optimum Detector for Frequency-Hopped Waveforms The Filter Bank Combiner Spectrum Analyzers Narrowband Signal Spectrum Analyzer Performance Wideband Signal Spectrum Analyzer Performance Second-Order Cyclostationary Feature Detection Cyclostationary Processes The Baseband and Carrier Cyclostationarity BPSK Through a Filter and Squarer Circuit Balanced QPSK Through a Filter and Squarer Circuit Balanced OQPSK Through a Filter and Squarer Circuit MSK Through a Filter and Squarer Circuit Frequency-Hopped Signals with MFSK Through a Filter and Squarer Circuit 800

Contents xvu 11.4.8 Slow Frequency-Hopped Signals with DPSK Data Modulation Through a Filter and Squarer Circuit 802 11.4.9 Delay and Multiply Chip Rate Detectors with Balanced QPSK 804 11.

12 Contents xvu Slow Frequency-Hopped Signals with DPSK Data Modulation Through a Filter and Squarer Circuit Delay and Multiply Chip Rate Detectors with Balanced QPSK Performance of a Chip Rate Detector for BPSK Frequency Estimation of an Unmodulated Tone with a Limiter Discriminator Summary 812 References 813 Selected Bibliography 814 Problems 814 Appendix 11A Samples from a Bandpass Filtered Gaussian Random Process 816 Chapter 12 Lock Detector Theory and Absorbing Markov Chains Introduction Absorbing Markov Chains The Fundamental Matrix Mean and Variance of the Number of Times a Process Is in a Transient State Mean and Variance of the Number of Times a Process Is in a Transient State General Case The Probability of Starting in a Transient State and Ending in a Persistent State Lock Detector Performance Lock Detector System Models Residual Carrier Loop Lock Detector Block Diagram Model Suppressed Carrier Lock Detector PN Code Acquisition Lock Detector A Frequency-Hopping Lock Detector for SFH/DPSK Summary 843 References 843 Selected Bibliography 843 Problems 843 About the Author 847 Index 849

PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS

PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS By DON TORRIERI Springer ebook ISBN: 0-387-22783-0 Print ISBN: 0-387-22782-2 2005 Springer Science