《通信原理与实验 Principles and Experiments of Communications》课程参考书：John G. Proakis Masoud Salehi《Fundamentals of Communication Systems》（Second Edition）

Preface This book is intended as a senior-level undergraduate textbook on communication systems for Electrical Engineering majors.Its primary objective is to introduce the basic techniques used in modern communication systems and to provide fundamental tools and methodolo- gies used in the analysis and design of these systems.Although the book is mainly written as an undergraduate-level textbook,it can be equally useful to the practicing engineer,or as a self-study tool. The emphasis of the book is on digital communication systems,which are treated in detail in Chapters 7 through 15.These systems are the backbone of modern commu- nication systems,including new generations of wireless communication systems,satellite communications,and data transmission networks.Traditional analog communication sys- tems are also covered in due detail in Chapters 3,4,and 6.In addition,the book provides detailed coverage of the background required for the course in two chapters,one on linear system analysis with emphasis on the frequency-domain approach and Fourier techniques, and one on probability,random variables,and random processes.Although these topics are now covered in separate courses in the majority of Electrical Engineering programs,it is the experience of the authors that the students frequently need to review these topics in a course on communications,and therefore it is essential to have quick access to the relevant material from these courses.It is also assumed that the students taking this course have a background in calculus,linear algebra,and basic electric circuits. NEW TO THIS EDITION The following are the major new features in the Second Edition of Fundamentals of Com- munication Systems: Major reorganization of basic digital modulation methods based on geometric repre- sentation of signals Expanded coverage of carrier phase estimation and symbol synchronization -New chapter on multicarrier modulation and OFDM -New and expanded coverage of iterative decoding of turbo codes and LDPC codes -New section on multiple antenna (MIMO)systems for radio channels New chapter on spread spectrum signals and systems ORGANIZATION OF THE BOOK The book starts with a brief review of communication systems in Chapter 1,followed by methods of signal representation and system analysis in both time and frequency domains xvii

Preface This book is intended as a senior-level undergraduate textbook on communication systems for Electrical Engineering majors. Its primary objective is to introduce the basic techniques used in modern communication systems and to provide fundamental tools and methodolo￾gies used in the analysis and design of these systems. Although the book is mainly written as an undergraduate-level textbook, it can be equally useful to the practicing engineer, or as a self-study tool. The emphasis of the book is on digital communication systems, which are treated in detail in Chapters 7 through 15. These systems are the backbone of modern commu￾nication systems, including new generations of wireless communication systems, satellite , communications, and data transmission networks. Traditional analog communication sys￾tems are also covered in due detail in Chapters 3, 4, and 6. In addition, the book provides detailed coverage of the background required for the course in two chapters, one on linear system analysis with emphasis on the frequency-domain approach and Fourier techniques, and one on probability, random variables, and random processes. Although these topics are now covered in separate courses in the majority of Electrical Engineering programs, it is the experience of the authors that the students frequently need to review these topics in a course on communications, and therefore it is essential to have quick access to the relevant material from these courses. It is also assumed that the students taking this course have a background in calculus, linear algebra, and basic electric circuits. NEW TO THIS EDITION The following are the major new features in the Second Edition of Fundamentals of Com￾munication Systems: Major reorganization of basic digital modulation methods based on geometric repre￾sentation of signals - Expanded coverage of carrier phase estimation and symbol synchronization New chapter on multicarrier modulation and OFDM - New and expanded coverage of iterative decoding of turbo codes and LDPC codes - New section on multiple antenna (MIMO) systems for radio channels - New chapter on spread spectrum signals and systems ORGANIZATION OF THE BOOK The book starts with a brief review of communication systems in Chapter 1, followed by methods of signal representation and system analysis in both time and frequency domains xvii

xviii Preface in Chapter 2.Emphasis is placed on the Fourier series and the Fourier transform represen- tation of signals and the use of transforms in linear systems analysis. Chapters 3 and 4 cover the modulation and demodulation of analog signals.In Chapter 3,amplitude modulation (AM)is covered.In Chapter 4,frequency modulation (FM)and phase modulation (PM)are covered.AM and FM radio broadcasting are also treated in these chapters. In Chapter 5,we present a review of the basic definitions and concepts in proba- bility and random processes.Special emphasis is placed on Gaussian random processes, which provide mathematically treatable models for additive noise disturbances.Both time- domain and frequency-domain representations of random signals are presented. Chapter 6 covers the effects of additive noise in the demodulation of amplitude- modulated(AM)and angle-modulated(FM,PM)analog signals and a comparison of these analog signal modulations in terms of their signal-to-noise ratio performance.We also present the characterization of thermal noise and the effect of transmission losses in analog communication systems. Chapter 7 is devoted to analog-to-digital conversion.The sampling theorem and quantization techniques are treated first,followed by waveform encoding methods includ- ing PCM,DPCM,and DM.This chapter concludes with brief discussion of LPC speech decoding and the JPEG standard for image compression. Chapter 8 treats basic digital modulation methods and their performance in AWGN channels.The methods described are binary antipodal and orthogonal signals,and M-ary pulse amplitude modulation(PAM),phase-shift keying(PSK),and quadrature amplitude modulation(QAM).These types of digital signals are characterized in terms of their geo- metric representation.The optimum demodulation of these signals is derived based on the maximum a posteriori and maximum-likelihood criteria.In addition,we also describe methods for carrier phase estimation using a phase-locked loop (PLL),and symbol syn- chronization. In Chapter 9,we treat multidimensional digital modulation signals based on a geo- metric representation of such signals and derive their performance when transmitted in an AWGN channel.Signal types considered include orthogonal signals,biorthogonal sig- nals,simplex signals,binary-coded signals,and frequency-shift keying(FSK).Continuous- phase FSK(CPFSK)and its spectral characteristics are also treated. In Chapter 10,we consider the transmission of digital signals in bandlimited AWGN channels.The effect of channel distortion on the transmitted signals is shown to result in intersymbol interference (ISD).Then,the design of signals that eliminate or control the effect of ISI is described.Finally,we treat the design of adaptive equalizers for suppressing ISI in the channel distorted received signal. The focus of Chapter 11 is on digital signal transmission via multicarrier modula- tion and orthogonal frequency-division multiplexing(OFDM).The implementation of the OFDM modulator and demodulator,based on the use of the FFT algorithm,is described. Additional topics treated include the spectral characteristics of OFDM signals and methods for reducing the peak-to-average power ratio (PAR)in OFDM signals.Finally,we present several applications of OFDM in current digital communication systems

xviii Preface in Chapter 2. Emphasis is placed on the Fourier series and the Fourier transform represen￾tation of signals and the use of transforms in linear systems analysis. Chapters 3 and 4 cover the modulation and demodulation of analog signals. In Chapter 3, amplitude modulation (AM) is covered. In Chapter 4, frequency modulation (FM) and phase modulation (PM) are covered. AM and FM radio broadcasting are also treated in these chapters. In Chapter 5, we present a review of the basic definitions and concepts in proba￾bility and random processes. Special emphasis is placed on Gaussian random processes, which provide mathematically treatable models for additive noise disturbances. Both time￾domain and frequency-domain representations of random signals are presented. Chapter 6 covers the effects of additive noise in the demodulation of amplitude￾modulated (AM) and angle-modulated (FM, PM) analog signals and a comparison of these analog signal modulations in terms of their signal-to-noise ratio performance. We also present the characterization of thermal noise and the effect of transmission losses in analog communication systems. Chapter 7 is devoted to analog-to-digital conversion. The sampling theorem and quantization techniques are treated first, followed by waveform encoding methods includ￾ing PCM, DPCM, and DM. This chapter concludes with brief discussion of LPC speech decoding and the JPEG standard for image compression. Chapter 8 treats basic digital modulation methods and their performance in AWGN channels. The methods described are binary antipodal and orthogonal signals, and M-ary pulse amplitude modulation (PAM), phase-shift keying (PSK), and quadrature amplitude modulation (QAM). These types of digital signals are characterized in terms of their geo￾metric representation. The optimum demodulation of these signals is derived based on the maximum a posteriori and maximum-likelihood criteria. In addition, we also describe methods for carrier phase estimation using a phase-locked loop (PLL), and symbol syn￾chronization. In Chapter 9, we treat multidimensional digital modulation signals based on a geo￾metric representation of such signals and derive their performance when transmitted in an AWGN channel. Signal types considered include orthogonal signals, biorthogonal sig￾nals, simplex signals, binary-coded signals, and frequency-shift keying (FSK). Continuous￾phase FSK (CPFSK) and its spectral characteristics are also treated. In Chapter 10, we consider the transmission of digital signals in bandlimited AWGN channels. The effect of channel distortion on the transmitted signals is shown to result in intersymbol inte1ference (ISi). Then, the design of signals that eliminate or control the effect of ISi is described. Finally, we treat the design of adaptive equalizers for suppressing ISi in the channel distorted received signal. The focus of Chapter 11 is on digital signal transmission via multicarrier modula￾tion and orthogonal frequency-division multiplexing (OFDM). The implementation of the OFDM modulator and demodulator, based on the use of the FFT algorithm, is described. Additional topics treated include the spectral characteristics of OFDM signals and methods for reducing the peak-to-average power ratio (PAR) in OFDM signals. Finally, we present several applications of OFDM in current digital communication systems

Preface xix In Chapter 12,we present the basic limits on communication of information,includ- ing the information content of memoryless sources,efficient coding of the source out- put,and the capacity of the AWGN channel.Two widely used algorithms for encoding the output of digital sources,namely,the Huffman coding algorithm and the Lempel-Ziv algorithm,are also described. In Chapter 13,we treat channel coding and decoding.Linear block codes and con- volutional codes are described for enhancing the performance of a digital communication system in the presence of AWGN.Both hard-decision and soft-decision decoding of block and convolutional codes are treated.Coding for bandwidth-limited channels (trellis-coded modulation),turbo codes,and low-density parity check codes are also treated. In Chapter 14,we treat the characterization of physical wireless channels and the construction of mathematical models for time-varying,fading multipath channels.The per- formance of binary modulation in Rayleigh fading channels is determined and the benefits of signal diversity for combating signal fading is demonstrated.The RAKE demodulator is described and its performance on frequency selective channels is evaluated.Also treated in this chapter is the use of multiple transmit and receive antennas for increasing the transmis- sion rate and obtaining signal diversity in wireless communication systems.Methods for mapping digital signals for transmission on multiple antennas are also presented,including block coding methods such as the Alamouti code and trellis codes.The final topic treated in this chapter is link budget analysis for radio channels. The final chapter of this book introduces the reader to spread-spectrum digital com- munication techniques and their use in combating interference,both intentional (jamming) and unintentional,the latter arising from other users of the channel.In particular,we treat direct sequence (DS)spread spectrum and frequency-hopping(FH)spread spectrum,and their performance characteristics in the presence of interference.Also treated is the gener- ation of pseudo-noise(PN)sequences for use in spreading the spectrum of the transmitted signal.The final topic of this chapter describes the use of spread spectrum signals in digital cellular communication systems,including 2nd-,3rd-,and 4th-generation(2G,3G,4G) cellular systems. Throughout the book many worked examples are provided to emphasize the use of the techniques developed in theory.Following each chapter are a large number of prob- lems at different levels of difficulty.The problems are followed by a selection of com- puter problems,which usually ask for simulation of various algorithms developed in that chapter using MATLAB.The solutions to the MATLAB problems are made available at www.pearsonhighered.com. Acknowledgments We wish to thank the reviewers of the first and second editions of this book(Selin Aviyente, Michigan State University;Costas Georghiades,Texas A&M University;Dennis Goeckel, University of Massachusetts,Amherst;Bijan Mobasseri,Villanova University;Robert Morelos-Zaragoza,San Jose State University;Ahmad Safaai-Jazi,Virginia Tech;Lei Wei

Preface xix In Chapter 12, we present the basic limits on communication of information, includ￾ing the information content of memoryless sources, efficient coding of the source out￾put, and the capacity of the AWGN channel. Two widely used algorithms for encoding the output of digital sources, namely, the Huffman coding algorithm and the Lempel-Ziv algorithm, are also described. In Chapter 13, we treat channel coding and decoding. Linear block codes and con￾volutional codes are described for enhancing the performance of a digital communication system in the presence of AWGN. Both hard-decision and soft-decision decoding of block and convolutional codes are treated. Coding for bandwidth-limited channels (trellis-coded modulation), turbo codes, and low-density parity check codes are also treated. In Chapter 14, we treat the characterization of physical wireless channels and the construction of mathematical models for time-varying, fading multipath channels. The per￾formance of binary modulation in Rayleigh fading channels is determined and the benefits of signal diversity for combating signal fading is demonstrated. The RAKE demodulator is � described and its performance on frequency selective channels is evaluated. Also treated in this chapter is the use of multiple transmit and receive antennas for increasing the transmis￾sion rate and obtaining signal diversity in wireless communication systems. Methods for mapping digital signals for transmission on multiple antennas are also presented, including block coding methods such as the Alamouti code and trellis codes. The final topic treated in this chapter is link budget analysis for radio channels. The final chapter of this book introduces the reader to spread-spectrum digital com￾munication technJ.ques and their use in combating interference, both intentional Uamming) and unintentional, the latter arising from other users of the channel. In particular, we treat direct sequence (DS) spr,ead spectrum and frequency-hopping (FH) spread spectrum, and their performance characteristics in the presence of interference. Also treated is the gener￾ation of pseudo-noise (PN) sequences for use in spreading the spectrum of the transmitted signal. The final topic of this chapter describes the use of spread spectrum signals in digital cellular communication systems, including 2nd-, 3rd-, and 4th-generation (2G, 3G, 4G) cellular systems. Throughout the book many worked examples are provided to emphasize the use of the techniques developed in theory. Following each chapter are a large number of prob￾lems at different levels of difficulty. The problems are followed by a selection of com￾puter problems, which usually ask for simulation of vaiious algorithms developed in that chapter using MATLAB. The solutions to the MATLAB problems are made available at www.pearsonhighered.com. Acknowledgments We wish to thank the reviewers of the first and second editions of this book (Selin Aviyente, Michigan State University; Costas Georghiades, Texas A&M University; Dennis Goeckel, University of Massachusetts, Amherst; Bijan Mobasseri, Villanova University; Robert Morelos-Zaragoza, San Jose State University; Ahmad Safaai-Jazi, Virginia Tech; Lei Wei

XX Preface University of Central Florida;and Stephen Wilson,University of Virginia)for their com- ments and recommendations.Their suggestions have resulted in significant improvements to the various topics covered in this book. John G.Proakis Adjunct Professor, University of California at San Diego and Professor Emeritus, Northeastern University, Masoud Salehi Northeastern University

xx Preface University of Central Florida; and Stephen Wilson, University of Virginia) for their com￾ments and recommendations. Their suggestions have resulted in significant improvements to the various topics covered in this book. John G. Proakis Adjunct Professor, University of California at San Diego and Professor Emeritus, Northeastern University, Masoud Salehi Northeastern University

CHAPTER Introduction Every day,in our work and in our leisure time,we use and come in contact with a variety of modern communication systems and communication media,the most common being the telephone,radio,and television.Through these media,we are able to communicate (nearly)instantaneously with people on different continents,transact our daily business, and receive information about various developments and noteworthy events that occur all around the world.Electronic mail and facsimile transmission have made it possible to rapidly communicate written messages across great distances. Can you imagine a world without telephones,radios,and televisions?Yet,when you think about it,most of these modern communication systems were invented and developed during the past century.Here,we present a brief historical review of major developments within the last 200 years'that have had a major role in the development of modern commu- nication systems. 1.1 HISTORICAL REVIEW Telegraphy and Telephony.One of the earliest inventions of major significance to communications was the invention of the electric battery by Alessandro Volta in 1799. This invention made it possible for Samuel Morse to develop the electric telegraph,which he demonstrated in 1837.The first telegraph line linked Washington with Baltimore and became operational in May 1844.Morse devised the variable-length binary code given in Table 1.1,in which letters of the English alphabet were represented by a sequence of dots and dashes (code words).In this code,more frequently occurring letters are represented by short code words,while less frequently occurring letters are represented by longer code words. The Morse code was the precursor to the variable-length source coding method, which is described in Chapter 12.It is remarkable that the earliest form of electrical com- munications that was developed by Morse,namely,telegraphy,was a binary digital com- munication system in which the letters of the English alphabet were efficiently encoded into corresponding variable-length code words with binary elements

Introduction �Every day, in our work and in our leisure time, we use and come in contact with a variety of modern communication systems and communication media, the most common being the telephone, radio, and television. Through these media, we are able to communicate (nearly) instantaneously with people on different continents, transact our daily business, and receive information about various developments and noteworthy events that occur all around the world. Electronic mail and facsimile transmission have made it possible to rapidly communicate written messages across great distances. Can you imagine a world without telephones, radios, and televisions? Yet, when you think about it, m©st of these modern communication systems were invented and developed during the past century. Here, we present a brief historical review of major developments within the last 200 years'that have had a major role in the development of modern commu￾nication systems. 1.1 HISTORICAL REVIEW Telegraphy and Telephony. One of the earliest inventions of major significance to communications was the invention of the electric battery by Alessandro Volta in 1799. This invention made it possible for Samuel Morse to develop the electric telegraph, which he demonstrated in 1837. The first telegraph line linked Washington with Baltimore and became operational in May 1844. Morse devised the variable-length binary code given in Table 1.1, in which letters of the English alphabet were represented by a sequence of dots and dashes (code words). In this code, more frequently occurring letters are represented by sho1t code words, while less frequently occurring letters are represented by longer code words. The Morse code was the precursor to the variable-length source coding method, which is described in Chapter 12. It is remarkable that the earliest form of electrical com￾munications that was developed by Morse, namely, telegraphy, was a binary digital com￾munication system in which the letters of the English alphabet were efficiently encoded into corresponding variable-length code words with binary elements. 1