Wireless Communications: Principles and Practice

• Authors: Theodore S. Rappaport
• Venue: Wireless Communications: Principles and Practice
• Year: 1996

From the Book:PREFACE: PrefaceThe purpose of this text is to initiate the newcomer to cellular radio and wireless personal communications, one of the fastest growing fields in the engineering world. Technical concepts which are at the core of design, implementation, research, and invention of wireless communication systems are presented in an order that is conducive to understanding general concepts, as well as those specific to particular cellular and personal communication systems and standards. This text is based upon my experiences as an educator, researcher, and consultant, and is modeled from an academic course developed for electrical engineering students as well as a self-study course for practicing engineers and technicians, developed at the request of the Institute of Electrical and Electronics Engineers (IEEE). References to journal articles are used liberally throughout this text to enable the interested reader to delve into additional reading that is always required to master any field. However, for handbook or classroom use, or for those who find it difficult to pursue outside reading, this text has been written as a complete, self-contained teaching and reference book. Numerous examples and problems have been provided to help the reader solidify the material.This book has been designed for the student or practicing engineer who is already familiar with technical concepts such as probability, communication theory, and basic electromagnetics. However, like the wireless communications industry itself, this book combines material from many different technical disciplines, so it is unlikely that any one person will have had introductory courses for all of thetopicscovered. To accommodate a wide range of backgrounds, important concepts throughout the text are developed from first principles, so that readers learn the foundations of wireless communications. This approach makes it possible to use this book as a handbook within industry, or as a teaching tool in a classroom setting.The material and chapter sequence in this text have been adapted from an entry-level graduate course which I first taught in 1991 at the Virginia Polytechnic Institute and State University. Chapter 1 demonstrates the rapid growth of cellular radio throughout the world and provides a glimpse into the future. Chapter 2 covers cellular radio concepts such as frequency reuse and handoff, which are at the core of providing wireless communication service to subscribers on the move using limited radio spectrum. Chapter 2 also demonstrates how interference between mobiles and base stations affects the capacity of cellular systems. Chapter 3 presents radio propagation path loss and log-normal shadowing and describes different ways to model and predict the large-scale effects of radio propagation in many operating environments. Chapter 4 covers small-scale propagation effects such as fading, time delay spread, and Doppler spread, and describes how to measure and model the impact that signal bandwidth and motion have on the instantaneous received signal through the multipath channel. Radio wave propagation has historically been the most difficult problem to analyze and design for, since unlike a wired communication system which has a constant, stationary transmission channel (i.e., a wired path), radio channels are random and undergo shadowing and multipath fading, particularly when one of the terminals is in motion. Chapter 5 provides extensive coverage of the most common analog and digital modulation techniques used in mobile communications and demonstrates trade-offs that must be made in selecting a modulation method. Issues such as receiver complexity, modulation and demodulation implementation, bit error rate analysis for fading channels, and spectral occupancy are presented. Channel coding, adaptive equalization, and antenna diversity concepts are presented in Chapter 6. In portable radio systems where people communicate while walking or driving, these methods may be used individually or in tandem to improve the quality (that is, reduce the bit error rate) of digital mobile radio communications in the presence of fading and noise.Chapter 7 provides an introduction to speech coding. In the past decade there has been remarkable progress in decreasing the needed data rate of high quality digitized speech, which enables wireless system designers to match end-user services to network architectures. Principles which have driven the development of adaptive pulse code modulation and linear predictive coding techniques are presented, and how these techniques are used to evaluate speech quality in existing and proposed cellular, cordless, and personal communication systems are discussed. Chapter 8 introduces time, frequency, and code division multiple access, as well as more recent multiple access techniques such as packet reservation and space division multiple access. Chapter 8 also describes how each access method can accommodate a large number of mobile users and demonstrates how multiple access impacts capacity and the network infrastructure of a cellular system. Chapter 9 describes networking considerations for wide area wireless communication systems, and presents practical networking approaches that are in use or have been proposed for future wireless systems. Chapter 10 unites all of the material from the first nine chapters by describing and comparing the major existing and proposed cellular, cordless, and personal communication systems throughout the world. The trade-offs made in the design and implementation of wireless personal communications systems are illuminated in this final chapter. The compilation of the major wireless standards makes Chapter 10 particularly useful as a single source of information for a wide range of systems.Appendices which cover trunking theory, noise calculations, and the Gaussian approximation for spread spectrum code division systems provide details for those interested in solving practical wireless communications problems.For industry use, Chapters 1-4 and 8 will benefit working engineers in the cellular system design and radio frequency (RF) testing/maintenance/measurement areas. Chapters 5-7 are tailored for modem designers and digital signal processing (DSP) engineers new to wireless. Chapters 9 and 10 should have broad appeal to network operators and managers, as well as working engineers.To use this text at the undergraduate level, the instructor may wish to concentrate on Chapters 1-5, or Chapters 1-4, and 8, leaving the other chapters for treatment in a second semester undergraduate course or a graduate level course. Alternatively, traditional undergraduate courses on communications or network theory may find in Chapters 1, 2, 3, 5, 7, 8, and 9 useful material that can be inserted easily into the standard curriculum. In using this text at the graduate level, I have been successful in covering most of the material in Chapters 1-8 during a standard half-year semester. In Chapters 9 and 10, I have attempted to cover important but rarely compiled information on practical network implementations and worldwide standards.Without the help and ingenuity of several former Virginia Tech graduate students, this text could not have been written. I am pleased to acknowledge the help and encouragement of Rias Muhamed, Varun Kapoor, Kevin Saldanha, and Anil Doradla - students I met in class while teaching the course Cellular Radio and Personal Communications. Kevin Saldanha also provided camera ready copy for this text (which turned out to be no small task!). The assistance of these students in compiling and editing materials for several chapters of this text was invaluable, and they were a source of constant encouragement throughout the project. Others who offered helpful suggestions, and whose research efforts are reflected in portions of this text, include Scott Seidel, Joe Liberti, Dwayne Hawbaker, Marty Feuerstein, Yingie Li, Ken Blackard, Victor Fung, Weifang Huang, Prabhakar Koushik, Orlando Landron, Francis Dominique, and Greg Bump. Zhigang Rong, Jeff Laster, Michael Buehrer, Keith Brafford, and Sandip Sandhu also provided useful suggestions and helpful reviews of early drafts.This text benefits greatly from practical input provided by several industry reviewers. Roman Zaputowycz of Bell Atlantic Mobile Systems, Mike Bamburak of McCaw Communications, David McKay of Allen Telecom Group, Jihad Hermes of Cellular One, Robert Rowe of AirTouch Communications, William Gardner of Qualcomm, and John Snapp of Blue Ridge Cellular provided extremely valuable input as to what materials were most important, and how they could best be presented for students and practicing engineers. Marty Feuerstein of U.S. West NewVector and Mike Lord of Cellular One provided comprehensive reviews which have greatly improved the manuscript. The technical staff at Grayson Electronics also provided feedback and practical suggestions during the development of this text.From the academic perspective, a number of faculty in the wireless communications field provided useful suggestions which I readily incorporated. These reviewers include Prof. J. Keith Townsend of North Carolina State University and Prof. William H. Tranter of the University of Missouri-Rolla. Professors Jeffrey Reed and Brian Woerner of Virginia Tech also provided excellent recommendations from a teaching perspective. I am grateful for the invaluable contributions from all of these individuals.I am pleased to acknowledge the support of the National Science Foundation, the Advanced Research Project Agency, and the many sponsors and friends of the Mobile & Portable Radio Research Group, who have supported our research and educational activities in wireless communications since 1990. It is from the excellent faculty at Purdue University, particularly my advisor, Clare D. McGillem, that I formally learned about communications and how to build a research program. I consider myself fortunate to have been one of the many graduate students who was stimulated to pursue a dual career in engineering and education upon graduation from Purdue.Finally, it is a pleasure to acknowledge my family and students, who put up with my preoccupation on this project, Barbara Coburn and Jill Cals of the IEEE, who championed the IEEE self-study course on the same subject, and Karen Gettman and Camille Trentacoste of Prentice Hall, who commissioned this work and helped me bring this text to you. —Theodore S. Rappaport