Convolutional Encoder Representation. Formulation of the Convolutional Decoding Problem. Properties of Convolutional Codes. Other Convolutional Decoding Algorithms.
Reed-Solomon Codes. Interleaving and Concatenated Codes. Turbo Codes. Goals of the Communications System Designer. Error Probability Plane. Nyquist Minimum Bandwidth. Shannon-Hartley Capacity Theorem. Bandwidth Efficiency Plane. Modulation and Coding Trade-Offs. Defining, Designing, and Evaluating Systems. Bandwidth-Efficient Modulations. Modulation and Coding for Bandlimited Channels. Trellis-Coded Modulation. Receiver Synchronization. Network Synchronization. Allocation of the Communications Resource.
Multiple Access Communications System and Architecture. Access Algorithms. Spread-Spectrum Overview. Pseudonoise Sequences. Direct-Sequence Spread-Spectrum Systems. Frequency Hopping Systems. Jamming Considerations. Commercial Applications. Cellular Systems.
Amplitude Quantizing. Differential Pulse-Code Modulation. Adaptive Prediction. Block Coding. Transform Coding. Source Coding for Digital Data. Examples of Source Coding. Models, Goals, and Early Cipher Systems.
The Secrecy of a Cipher System. Practical Security. Stream Encryption. Public Key Cryptosystems. Pretty Good Privacy. The Challenge of Communicating over Fading Channels. Characterizing Mobile-Radio Propagation. Signal Time-Spreading. Time Variance of the Channel Caused by Motion. Mitigating the Degradation Effects of Fading. Signals, Spectra, and Linear Systems. Fourier Techniques for Linear System Analysis. Fourier Transform Properties.
Useful Functions. Tables of Fourier Transforms and Operations. Bayes' Theorem. Decision Theory. Signal Detection Example. Pearson offers affordable and accessible purchase options to meet the needs of your students. Connect with us to learn more.
He is now head of advanced systems at Communications Engineering Services, a consulting company he founded in We're sorry! We don't recognize your username or password. Please try again. The work is protected by local and international copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning.
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If You're an Educator Download instructor resources Additional order info. Description For courses in Digital Communications. NEW - Expanded coverage of error-correction coding —Particularly in the areas of Reed-Solomon codes, turbo codes, and trellis-coded modulation. NEW - Chapter on fading channels —And how to mitigate their degrading effects. Methodically organizes the nomenclature of fading channels, the fading phenomena, and their effects, making them easier to grasp. NEW - Expanded explanations and descriptions of essential digital communication concepts.
In fulfillment of this objective, there has arisen an impres- sive assortment of signal processing techniques. The book develops these techniques in the context of a unified structure. The structure, in block diagram form, appears at the beginning of each chapter; blocks in the diagram are emphasized, when appropriate, to correspond to the subject of that chapter. Major purposes of the book are to add organization and structure to a field that has grown and continues to grow rapidly, and to insure awareness of the "big picture" even while delving into the details.
Signals and key processing steps are traced from the information source through the transmitter, channel, receiver, and ultimately to the information sink. Signal transformations are organized according to nine functional classes: Formatting and source coding, Baseband signaling, Band- pass signaling, Equalization, Channel coding, Muliplexing and multiple access, Spreading, Encryption, and Synchronization.
Throughout the book, emphasis is placed on system goals and the need to trade off basic system parameters such as signal-to-noise ratio, probability of error, and bandwidth expenditure. Some basic ideas of random variables and the additive white Gaussian noise AWGN model are re- viewed. Also, the relationship between power spectral density and autocorrelation, and the basics of signal transmission through linear systems are established.
Chap- ter 2 covers the signal processing step, known as formatting, in order to render an information signal compatible with a digital system. Chapter 3 emphasizes base- band signaling, the detection of signals in Gaussian noise, and receiver optimiza- tion.
Chapter 5 deals with link analysis, an im- portant subject for providing overall system insight; it considers some subtleties that are often missed. Chapters 6, 7, and 8 deal with channel coding—a cost- effective way of providing a variety of system performance trade-offs. Chapter 6 emphasizes linear block codes, Chapter 7 deals with convolutional codes, and Chap- ter 8 deals with Reed-Solomon codes and concatenated codes such as turbo codes.
It also treats the important area of coded modulation, particularly trellis-coded modulation. Chapter 10 deals with synchronization for digital systems. It covers phase-locked loop implementation for achieving carrier synchronization. It covers bit synchronization, frame synchronization, and network synchronization, and it introduces some ways of performing synchronization using digital methods.
Chapter 11 treats multiplexing and multiple access. It explores techniques that are available for utilizing the communication resource efficiently. Chapter 12 intro- duces spread spectrum techniques and their application in such areas as multiple access, ranging, and interference rejection.
This technology is important for both military and commercial applications. Chapter 13 deals with source coding which is a special class of data formatting. Both formatting and source coding involve digiti- zation of data; the main difference between them is that source coding additionally involves data redundancy reduction. Rather than considering source coding imme- diately after formatting, it is purposely treated in a later chapter so as not to inter- rupt the presentation flow of the basic processing steps.
It includes some classical concepts, as well as a class of systems called public key cryptosystems, and the widely used E-mail encryption software known as Pretty Good Privacy PGP. Chapter 15 deals with fading chan- nels. Here, we deal with applications, such as mobile radios, where characteriza- tion of the channel is much more involved than that of a nonfading one. The design of a communication system that will withstand the degradation effects of fading can be much more challenging than the design of its nonfading counterpart.
In this chapter, we describe a variety of techniques that can mitigate the effects of fading, and we show some successful designs that have been implemented. It is assumed that the reader is familiar with Fourier methods and convolu- tion.
It also assumed that the reader has a knowledge of basic probability and has some familiarity with random variables. Appendix B builds on these disciplines for a short treatment on statistical decision theory with emphasis on hypothesis testing—so important in the under- standing of detection theory.
A new section, Appendix E, has been added to serve as a short tutorial on s-domain, z-domain, and digital filtering. If the book is used for a two-term course, a simple partitioning is suggested; the first seven chapters can be taught in the first term, and the last eight chapters in the second term. If the book is used for a one-term introductory course, it is sug- gested that the course material be selected from the following chapters: 1, 2, 3, 4, 5, 6, 7, 9, 10, I have re- ceived an abundance of such assistance, for which I am deeply grateful.
For their generous help, I want to thank Dr. Andrew Viterbi, Dr. Chuck Wheatley, Dr. Ed Tiedeman, Dr. Joe Odenwalder, and Serge Willinegger of Qualcomm. I also want to thank Dr. Bob Bogusch of Mission Research, Dr. Bob Price and Frank Amoroso. I also want to acknowledge those people who played a big part in helping me with the first edition of the book. They are: Dr. Jim Omura, Dr. Adam Lender, and Dr. Todd Citron. I want to thank Dr. Also, thanks to Michelle Landry for writing the sec- tions on Pretty Good Privacy in Chapter 14, and to Andrew Guidi for contributing end-of-chapter problems in Chapter Maury Schiff of Elanix, who put up with my incessant argumentative discussions anytime that I called on them.
I also want to thank my very best teachers—they are my students at the University of California, Los Angeles, as well as those students all over the world who attended my short courses.
Their questions motivated me and provoked me to write this second edition. I hope that I have answered all their questions with clarity. I thank Rose Kernan, my editor, for watching over me and this project, and I thank Bernard Goodwin, Publisher at Prentice Hall, for indulging me and believing in me.
His recommendations were invaluable. Finally, I am extremely grateful to my wife, Gwen, for her encourage- ment, devotion, and valuable advice. She protected me from the "slings and ar- rows" of everyday life, making it possible for me to complete this second edition.
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