Digital Communications with Emphasis on Data Modems: Theory, Analysis, Design, Simulation, Testing, and Applications

This book uses a practical approach in the application of theoretical concepts to digital communications in the design of software defined radio modems. This book discusses the design, implementation and performance verification of waveforms and algorithms appropriate for digital data modulation and demodulation in modern communication systems. Using a building-block approach, the author provides an introductory to the advanced understanding of acquisition and data detection using source and executable simulation code to validate the communication system performance with respect to theory and design specifications. The author focuses on theoretical analysis, algorithm design, firmware and software designs and subsystem and system testing. This book treats system designs with a variety of channel characteristics from very low to optical frequencies. This book offers system analysis and subsystem implementation options for acquisition and data detection appropriate to the channel conditions and system specifications, and provides test methods for demonstrating system performance. This book also: Outlines fundamental system requirements and related analysis that must be established prior to a detailed subsystem design Includes many examples that highlight various analytical solutions and case studies that characterize various system performance measures Discusses various aspects of atmospheric propagation using the spherical 4/3 effective earth radius model Examines Ionospheric propagation and uses the Rayleigh fading channel to evaluate link performance using several robust waveform modulations Contains end-of-chapter problems, allowing the reader to further engage with the text Digital Communications with Emphasis on Data Modems is a great resource for communication-system and digital signal processing engineers and students looking for in-depth theory as well as practical implementations.

Table of Contents:
Preface xxi Acknowledgments xxv Summary of Notations xxvii About the Cover xxix About the Companion Website xxxi 1 Mathematical Background and Analysis Techniques 1 1.1 Introduction 1 1.2 The Fourier Transform and Fourier Series 5 1.3 Pulse Distortion with Ideal Filter Models 16 1.4 Correlation Processing 19 1.5 Random Variables and Probability 20 1.6 Random Processes 41 1.7 The Matched Filter 44 1.8 The Likelihood and Log-Likelihood Ratios 46 1.9 Parameter Estimation 47 1.10 Modem Configurations and Automatic Repeat Request 55 1.11 Windows 57 1.12 Matrices Vectors and Related Operations 66 1.13 Often Used Mathematical Procedures 70 1.14 Often Used Mathematical Relationships 71 2 Digital Signal Processing and Modem Design Considerations 81 2.1 Introduction 81 2.2 Discrete Amplitude Sampling 81 2.3 Discrete-Time Sampling 87 2.4 Signal Reconstruction Following Discrete-Time Sampling 91 2.5 Baseband Sampling 92 2.6 Bandpass Sampling 92 2.7 Corrections for Nonideal Modulators and Demodulators 99 2.8 Multirate Signal Processing and Interpolation 106 Appendix 2A Amplitude Quantization Function Subprogram 121 Appendix 2B Hilbert Transform Parameters 122 Appendix 2C Derivation of Parabolic Interpolation Error 126 3 Digital Communications 133 3.1 Introduction 133 3.2 Digital Data Modulation and Optimum Demodulation Criteria 135 3.3 Information and Channel Capacity 139 3.4 Bit-Error Probability Bound on Memoryless Channel 148 3.5 Probability Integral and the Error Function 150 4 Phase Shift Keying (PSK) Modulation Demodulation and Performance 153 4.1 Introduction 153 4.2 Constant Envelope Phase-Modulated Waveforms 154 4.3 Non-Constant Envelope Phase-Modulated Waveforms 175 4.4 Phase-Modulated Waveform Spectrums and Performance 178 5 Frequency Shift Keying (FSK) Modulation Demodulation and Performance 207 5.1 Introduction 207 5.2 Coherent Detection of BFSK—Known Frequency and Phase 207 5.3 Noncoherent Detection of BFSK—Known Frequency and Unknown Phase 210 5.4 Case Studies: Coherent and Noncoherent BFSK Performance Simulation 211 5.5 Noncoherent Detection of BFSK—Unknown Frequency and Phase 214 5.6 BFSK Spectral Density with Arbitrary Modulation Index 219 6 Amplitude Shift Keying Modulation Demodulation and Performance 227 6.1 Introduction 227 6.2 Amplitude Shift Keying (ASK) 227 6.3 Quadrature Amplitude Modulation (QAM) 234 6.4 Alternate QAM Waveform Constellations 236 6.5 Case Study: 16-ary QAM Performance Evaluation 236 6.6 Partial Response Modulation 237 7 M-ary Coded Modulation 251 7.1 Introduction 251 7.2 Coherent Detection of Orthogonal Coded Waveforms 252 7.3 Noncoherent Detection of M-ary Orthogonal Waveforms 253 7.4 Coherent Detection of M-ary Biorthogonal Waveforms 256 8 Coding for Improved Communications 261 8.1 Introduction 261 8.2 Pulse Code Modulation 261 8.3 Gray Coding 268 8.4 Differential Coding 269 8.5 Pseudo-Random Noise Sequences 270 8.6 Binary Cyclic Codes 273 8.7 Cyclic Redundancy Check Codes 274 8.8 Data Randomizing Codes 276 8.9 Data Interleaving 277 8.10 Wagner Coding and Decoding 279 8.11 Convolutional Codes 283 8.12 Turbo and Turbo-Like Codes 299 8.13 LDPC Code and TPC 313 8.14 Bose-Chaudhuri-Hocquenghem Codes 315 Appendix 8A 328 Appendix 8B 329 9 Forward Error Correction Coding Without Bandwidth Expansion 339 9.1 Introduction 339 9.2 Multi-h M-ary CPM 340 9.3 Case Study: 2-h 4-ary 1REC CPM 350 9.4 Multiphase Shift Keying Trellis-Coded Modulation 362 9.5 Case Study: Four-State 8PSK-TCM Performance Over Satellite Repeater 367 10 Carrier Acquisition and Tracking 375 10.1 Introduction 375 10.2 Bandpass Limiter 377 10.3 Baseband Phaselock Loop Implementation 378 10.4 Phase-Error Generation 378 10.5 First-Order Phaselock Loop 380 10.6 Second-Order Phaselock Loop 380 10.7 Third-Order Phaselock Loop 390 10.8 Optimum Phase Tracking Algorithms 396 10.9 Squaring Loss Evaluation 406 10.10 Case Study: BPSK and QPSK Phaselock Loop Performance 408 10.11 Case Study: BPSK Phase Tracking Performance of a Disadvantaged Transmit Terminal 410 11 Waveform Acquisition 413 11.1 Introduction 413 11.2 CW Preamble Segment Signal Processing 416 11.3 Symbol Synchronization Preamble Segment 432 11.4 Start-of-Message (SOM) Preamble segment 452 11.5 Signal-to-Noise Ratio Estimation 452 12 Adaptive Systems 463 12.1 Introduction 463 12.2 Optimum Filtering—Wiener’s Solution 464 12.3 Finite Impulse Response-Adaptive Filter Estimation 465 12.4 Intersymbol Interference and Multipath Equalization 469 12.5 Interference and Noise Cancellation 472 12.6 Recursive Least Square (RLS) Equalizer 473 12.7 Case Study: LMS Linear Feedforward Equalization 474 12.8 Case Study: Narrowband Interference Cancellation 474 12.9 Case Study: Recursive Least Squares Processing 480 13 Spread-Spectrum Communications 485 13.1 Introduction 485 13.2 Spread-Spectrum Waveforms and Spectrums 487 13.3 Jammer and Interceptor Encounters 499 13.4 Communication Interceptors 502 13.5 Bit-Error Performance of DSSS Waveforms with Jamming 504 13.6 Performance of MFSK with Partial-Band Noise Jamming 512 13.7 Performance of DCMPSK with Partial-Band Noise Jamming 514 13.8 FHSS Waveforms with Multitone Jamming 515 13.9 Approximate Performance with Jammer Threats 521 13.10 Case Study: Terrestrial Jammer Encounter and Link-Standoff Ratio 522 14 Modem Testing Modeling and Simulation 531 14.1 Introduction 531 14.2 Statistical Sampling 532 14.3 Computer Generation of Random Variables 539 14.4 Baseband Waveform Description 545 14.5 Sampled Waveform Characterization 547 14.6 Case Study: BPSK Monte Carlo Simulation 548 14.7 System Performance Evaluation Using Quadrature Integration 550 14.8 Case Study: BPSK Bit-Error Evaluation with PLL Tracking 551 14.9 Case Study: QPSK Bit-Error Evaluation with PLL Tracking 553 15 Communication Range Equation and Link Analysis 557 15.1 Introduction 557 15.2 Receiver and System Noise Figures and Temperatures 560 15.3 Antenna Gain and Patterns 568 15.4 Rain Loss 571 15.5 Electric Field Wave Polarization 573 15.6 Phase-Noise Loss 578 15.7 Scintillation Loss 583 15.8 Multipath Loss 583 15.9 Interface Mismatch Loss 584 15.10 Miscellaneous System Losses 585 15.11 Nonlinear Power Amplifier Analysis and Simulation 585 15.12 Computer Modeling of TWTA and SSPA Nonlinearities 588 15.13 Establishing Signal Levels for Simulation Modeling 590 15.14 Case Study: Performance Simulation of SRRC-QPSK with SSPA Nonlinearity 592 15.15 Link Budget Analysis 596 16 Satellite Orbits 603 16.1 Introduction 603 16.2 Satellite Orbits 606 16.3 Earth Stations 607 16.4 Path Loss Doppler and Doppler-rate 609 16.5 Satellite Viewing 609 16.6 Satellite Orbit Selection 610 16.7 Satellite Orbit Position Estimation From Parameter Measurements 611 16.8 Case Study: Example Satellite Encounters 612 17 Communications Through Bandlimited Time-Invariant Linear Channels 617 17.1 Introduction 617 17.2 Inphase and Quadrature Channel Response 618 17.3 Inphase and Quadrature Channel Response to Arbitrary Signal 619 17.4 Pulse Modulated Carrier Signal Characteristics 621 17.5 Channel Response to a Pulsed Modulated Waveform 622 17.6 Example Performance Simulations 623 17.7 Example of Channel Amplitude and Phase Responses 624 17.8 Example Channel Amplitude Phase and Delay Functions 627 18 Communications in Fading Environments 633 18.1 Introduction 633 18.2 Ricean Fading Channels 634 18.3 Ricean Cumulative Distribution 635 18.4 Application of Ricean Channel Model 635 18.5 Performance of Several Binary Modulation Waveforms with Ricean Fading 636 18.6 Generation of Ricean Random Variables 639 18.7 Relationships Between Fading Channel Parameters 641 18.8 Diversity Techniques for Fading Channels 643 19 Atmospheric Propagation 649 19.1 Introduction 649 19.2 Communication Link Geometry for Curved Earth 650 19.3 Reflection 652 19.4 Case Study: LEO Satellite Multipath Propagation 654 19.5 Refraction 656 19.6 Diffraction 660 19.7 Longley-Rice Propagation Loss Model 661 19.8 Urban Suburban and Rural Environment Propagation Loss Models 663 19.9 Land Mobile Satellite Propagation Loss Models 665 19.10 Impulsive Noise Channel 667 19.11 Ocean Wind Wave Channel 676 19.12 Laser Communications Using Photomultiplier Detector 684 20 Ionospheric Propagation 699 20.1 Introduction 699 20.2 Electron Densities: Natural Environment 700 20.3 Electron Densities: Nuclear-Disturbed Environment 703 20.4 The Refractive Index and Signal Propagation 704 20.5 Signal Propagation in Severe Scintillation Environment 706 20.6 Propagation Disturbances Following Severe Absorption 712 20.7 Rayleigh Scintillation Channel Model 715 20.8 Scintillation Mitigation Techniques 721 20.9 Case Study: BPSK and DCBPSK Performance in Rayleigh Fading Channel 722 Appendix 20A 727 Appendix A: Classical Filters and Applications 733 Appendix B: Digital Filter Design and Applications 747 Appendix C: Detection of Signals in Noise 755 Index 769