Communication Systems Principles Using MATLAB®

Description

Preface History has probably never witnessed such a dramatic rise in technical sophistication, coupled with blanket penetration into everyday life, as has occurred in recent times with telecommunications. The combination of electronic systems, together with readily available programmable devices, provides endless possibilities for interconnecting what were previously separated and isolated means of communicating, both across the street and across the globe. How, then, is the college- or university-level student to come to grips with all this sophistication in just a few semesters of study? Human learning has not changed substantially, but the means to acquire knowledge and shape understanding certainly has. This is through the ability to experiment, craft, code, and create systems of our own making. This book recognizes that a valuable approach is that of learn-by-doing, experimenting, making mistakes, and altering our mental models as a result. Whilst there are many excellent reference texts on the subject available, they can be opaque and impenetrable to the newcomer. This book is not designed to simply offer a recipe for each current and emerging technology. Rather, the underpinning theories and ideas are explained in order to motivate the why does it work in this way? questions rather than how does technology X work? With these observations as a background, this book was designed to cover many fundamental topics in telecommunications but without the need to master a large body of theory whose relevance may not immediately be apparent. It is suitable for several one-semester courses focusing on one or more topics in radio and wireless modulation, reception and transmission, wired networks, and fiber-optic communications. This is then extended to packet networks and TCP/IP and then to digital source and channel coding and the basics of data encryption. The emphasis is on understanding, rather than regurgitating facts. Digital communications is addressed with the coverage of packet-switched networks, with many fundamental concepts such as routing via shortest path introduced with simple, concrete, and intuitive examples. The treatment of advanced telecommunication topics extends to OFDM for wireless modulation and public-key exchange algorithms for data encryption. The reader is urged to try the examples as they are given. MATLAB® was chosen as the vehicle for demonstrating many of the basic ideas, with code examples in every chapter as an integral part of the text, rather than an afterthought. Since MATLAB® is widely used by telecommunication engineers, many useful take-home skills may be developed in parallel with the study of each aspect of telecommunications. In addition to the coding and experimentation approach, many real-world examples are given where appropriate. Underpinning theory is given where necessary, and a Useful Preliminaries section at the start of each chapter serves to remind students of useful background theory, which may be required in order to understand the theoretical and conceptual developments presented within the chapter. Contents Preface xiii Acknowledgments xv Introduction xvii About the CompanionWebsite xxi 1 Signals and Systems 1 1.1 Chapter Objectives 1 1.2 Introduction 1 1.3 Signals and Phase Shift 2 1.4 System Building Blocks 3 1.4.1 Basic Building Blocks 3 1.4.2 Phase Shifting Blocks 4 1.4.3 Linear and Nonlinear Blocks 5 1.4.4 Filtering Blocks 8 1.5 Integration and Differentiation of aWaveform 10 1.6 Generating Signals 16 1.7 Measuring and Transferring Power 19 1.7.1 Root Mean Square 19 1.7.2 The Decibel 23 1.7.3 Maximum Power Transfer 25 1.8 System Noise 29 1.9 Chapter Summary 32 Problems 32 2 Wired,Wireless, and Optical Systems 37 2.1 Chapter Objectives 37 2.2 Introduction 37 2.3 Useful Preliminaries 38 2.3.1 Frequency Components When a SignalWaveform Is Known 38 2.3.2 Frequency Spectrum When a Signal Is Measured 42 2.3.3 Measuring the Frequency Spectrum in Practice 44 2.4 Wired Communications 50 2.4.1 Cabling Considerations 50 2.4.2 Pulse Shaping 52 2.4.3 Line Codes and Synchronization 62 2.4.4 Scrambling and Synchronization 66 2.4.5 Pulse Reflection 73 2.4.6 Characteristic Impedance of a Transmission Line 80 2.4.7 Wave Equation for a Transmission Line 83 2.4.8 StandingWaves 84 2.5 Radio andWireless 92 2.5.1 Radio-frequency Spectrum 92 2.5.2 Radio Propagation 92 2.5.3 Line-of-sight Considerations 96 2.5.4 Radio Reflection 97 2.5.5 RadioWave Diffraction 99 2.5.6 RadioWaves with a Moving Sender or Receiver 103 2.5.7 Sending and Capturing a Radio Signal 105 2.5.8 Processing aWireless Signal 119 2.5.9 Intermodulation 128 2.5.10 External Noise 131 2.6 Optical Transmission 132 2.6.1 Principles of Optical Transmission 132 2.6.2 Optical Sources 134 2.6.3 Optical Fiber 139 2.6.4 Optical Fiber Losses 145 2.6.5 Optical Transmission Measurements 147 2.7 Chapter Summary 150 Problems 151 3 Modulation and Demodulation 155 3.1 Chapter Objectives 155 3.2 Introduction 155 3.3 Useful Preliminaries 156 3.3.1 Trigonometry 157 3.3.2 Complex Numbers 159 3.4 The Need for Modulation 162 3.5 AmplitudeModulation 164 3.5.1 Frequency Components 167 3.5.2 Power Analysis 170 3.5.3 AM Demodulation 171 3.5.4 Variations on AM 173 3.6 Frequency and Phase Modulation 180 3.6.1 FM and PM Concepts 181 3.6.2 FM and PM Analysis 183 3.6.3 Generation of FM and PM Signals 185 3.6.4 The Spectrum of Frequency Modulation 186 3.6.5 Why Do the Bessel Coefficients Give the Spectrum of FM? 195 3.6.6 FM Demodulation 200 3.7 Phase Tracking and Synchronization 204 3.8 Demodulation Using IQ Methods 215 3.8.1 Demodulation of AM Using IQ Signals 216 3.8.2 Demodulation of PM Using IQ Signals 219 3.8.3 Demodulation of FM Using IQ Signals 222 3.9 Modulation for Digital Transmission 225 3.9.1 Digital Modulation 226 3.9.2 Recovering Digital Signals 228 3.9.3 Orthogonal Signals 237 3.9.4 Quadrature AmplitudeModulation 239 3.9.5 Frequency Division Multiplexing 242 3.9.6 Orthogonal Frequency Division Multiplexing 244 3.9.7 Implementing OFDM: The FFT 247 3.9.8 Spread Spectrum 254 3.10 Chapter Summary 261 Problems 261 4 Internet Protocols and Packet Delivery Algorithms 269 4.1 Chapter Objectives 269 4.2 Introduction 269 4.3 Useful Preliminaries 270 4.3.1 Packet Switching 270 4.3.2 Binary Operations 272 4.3.3 Data Structures and Dereferencing Data 272 4.4 Packets, Protocol Layers, and the Protocol Stack 277 4.5 Local Area Networks 281 4.5.1 Wired LANs 282 4.5.2 Wireless LANs 284 4.6 Device Packet Delivery: Internet Protocol 286 4.6.1 The Original IPv4 286 4.6.2 Extension to IPv6 286 4.6.3 IP Checksum 290 4.6.4 IP Addressing 294 4.6.5 Subnetworks 296 4.6.6 Network Address Translation 298 4.7 Network Access Configuration 300 4.7.1 MappingMAC to IP: ARP 301 4.7.2 IP Configuration: DHCP 302 4.7.3 Domain Name System (DNS) 302 4.8 Application Packet Delivery: TCP and UDP 303 4.9 TCP: Reliable Delivery and Network Fairness 309 4.9.1 Connection Establishment and Teardown 311 4.9.2 Congestion Control 311 4.9.3 TCP Timeouts 319 4.10 Packet Routing 321 4.10.1 Routing Example 322 4.10.2 Mechanics of Packet Forwarding 323 4.10.3 Routing Tasks 325 4.10.4 Forwarding Table Using Supernetting 326 4.10.5 Route Path Lookup 330 4.10.6 Routing Tables Based on Neighbor Discovery: Distance Vector 343 4.10.7 Routing Tables Based on Network Topology: Link State 348 4.11 Chapter Summary 359 Problems 359 5 Quantization and Coding 363 5.1 Chapter Objectives 363 5.2 Introduction 363 5.3 Useful Preliminaries 364 5.3.1 Probability Functions 364 5.3.2 Difference Equations and the z Transform 366 5.4 Digital Channel Capacity 369 5.5 Quantization 372 5.5.1 Scalar Quantization 373 5.5.2 Companding 379 5.5.3 Unequal Step Size Quantization 382 5.5.4 Adaptive Scalar Quantization 383 5.5.5 Vector Quantization 385 5.6 Source Coding 389 5.6.1 Lossless Codes 390 5.6.1.1 Entropy and Codewords 390 5.6.1.2 The Huffman Code 392 5.6.1.3 Adapting the Probability Table 404 5.6.2 Block-based Lossless Encoders 405 5.6.2.1 Sliding-Window Lossless Encoders 405 5.6.2.2 Dictionary-based Lossless Encoders 407 5.6.3 Differential PCM 409 5.6.3.1 Sample-by-sample Prediction 410 5.6.3.2 Adaptive Prediction 417 5.7 Image Coding 420 5.7.1 Block Truncation Algorithm 422 5.7.2 Discrete Cosine Transform 425 5.7.3 Quadtree Decomposition 430 5.7.4 Color Representation 431 5.8 Speech and Audio Coding 433 5.8.1 Linear Prediction for Speech Coding 434 5.8.2 Analysis by Synthesis 439 5.8.3 Spectral Response and NoiseWeighting 440 5.8.4 Audio Coding 442 5.9 Chapter Summary 447 Problems 447 6 Data Transmission and Integrity 453 6.1 Chapter Objectives 453 6.2 Introduction 453 6.3 Useful Preliminaries 454 6.3.1 Probability Error Functions 454 6.3.2 Integer Arithmetic 458 6.4 Bit Errors in Digital Systems 461 6.4.1 Basic Concepts 461 6.4.2 Analyzing Bit Errors 463 6.5 Approaches to Block Error Detection 470 6.5.1 Hamming Codes 472 6.5.2 Checksums 478 6.5.3 Cyclic Redundancy Checks 482 6.5.4 Convolutional Coding for Error Correction 489 6.6 Encryption and Security 507 6.6.1 Cipher Algorithms 508 6.6.2 Simple Encipherment Systems 509 6.6.3 Key Exchange 512 6.6.4 Digital Signatures and Hash Functions 519 6.6.5 Public-key Encryption 520 6.6.6 Public-key Authentication 522 6.6.7 Mathematics Underpinning Public-key Encryption 522 6.7 Chapter Summary 526 Problems 526 References 531 Index 541