PRINCIPLES OF MOBILE COMMUNICATION

PRINCIPLES OF MOBILE COMMUNICATION

by

Gordon L. Stuber Georgia Institute of Technology

Springer Science+Business Media, LLC

Library of Congress Cataloging-in-Publication Data

A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN 978-1-4757-6270-9 ISBN 978-1-4757-6268-6 (eBook) DOI 10.1007/978-1-4757-6268-6

Copyright © 1996 by Springer Science+Business Media New York Originally published by Kluwer Academic Publishers in 1999 Third Printing 1999. Softcover reprint of the hardcover 1 st edition 1999

AII rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, mechanical, photo-copying, recording, or otherwise, without the prior written permission of the publisher, Kluwer Academic Publishers, 101 Philip Drive, Assinippi Park, Norwell, Massachusetts 02061

Printed an acid1ree pa per.

To my parents

CONTENTS

PREFACE xi

1 INTRODUCTION 1 1.1 Wireless Systems and Standards 3 1.2 Frequency Reuse and the Cellular Concept 14 1.3 Mobile Radio Propagation Environment 15 1.4 Co-channel Interference and Noise 19 1.5 Modulation Techniques 22 1.6 Handoft"s and Channel Assignment 25 1.7 Spectral Efficiency and Grade of Service 30

2 PROPAGATION MODELING 35 2.1 Frequency-Non-Selective (Flat) Multipath-Fading 37 2.2 Frequency-Selective Multipath-Fading 63 2.3 Laboratory Simulation of Multipath-Fading Channels 73 2.4 Shadowing 87 2.5 Path Loss Models 93

3 CO-CHANNEL INTERFERENCE 115 3.1 Multiple Log-normal Interferers 117 3.2 Probability of CCI 124 3.3 Multiple RiceanjRayleigh Interferers 129 3.4 Multiple Log-normal Nakagami Interferers 131 3.5 Multiple Log-normal RiceanjRayleigh Interferers 135

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4 MODULATED SIGNALS AND THEIR POWER SPECTRAL DENSITIES 143 4.1 Analog Frequency Modulation 144 4.2 Basic Description of Digitally Modulated Signals 158 4.3 Amplitude Shift Keying (ASK) 164 4.4 Orthogonal Frequency Division Multiplexing (OFDM) 166 4.5 Phase Shift Keying (PSK) 169 4.6 1I"/4-DQPSK 170 4.7 Continuous Phase Modulation (CPM) 172 4.8 Minimum Shift Keying (MSK) 177 4.9 Partial Response CPM 180 4.10 Power Spectral Densities of Digitally Modulated Signals 187

5 DIGITAL SIGNALING ON FLAT FADING CHANNELS 215 5.1 Vector Representation of Received Signals 216 5.2 Detection of Known Signals in Additive White Gaussian Noise 219 5.3 Error Probability with Coherent Detection 222 5.4 Differential Detection 234 5.5 Diversity Techniques 238

6 DIGITAL SIGNALING ON lSI CHANNELS 263 6.1 Overview of Equalization Techniques 264 6.2 Modeling of lSI Channels 269 6.3 Optimum Receiver for lSI Channels with AWGN 273 6.4 Symbol-by-Symbol Equalizers 281 6.5 Sequence Estimation 295 6.6 Error Probability for MLSE on lSI Channels 308 6.7 Error Probability for Fractionally-spaced MLSE Receivers 323

7 BANDWIDTH EFFICIENT CODING 341 7.1 Convolutional Codes 345 7.2 Trellis Coded Modulation 351 7.3 Coded Performance on AWGN Channels 357 7.4 Coded Performance on Interleaved Flat Fading Channels 362 7.5 Coded Performance on Fading lSI Channels 373

Contents IX

7.6 Evaluation of Union Bounds for TCM 383 7.7 TCM on Equalized lSI Channels 391

8 CODE DIVISION MULTIPLE ACCESS 409 8.1 Introduction to DS and FH Spread Spectrum 411 8.2 Spreading Sequences and Their Correlation Functions 417 8.3 DS Spread Spectrum on Frequency-Selective Fading Channels 425 8.4 Error Probability for DS CDMA on AWGN Channels 434 8.5 Performance Analysis of Cellular CDMA 443

9 CELLULAR COVERAGE PLANNING 467 9.1 Cell Sectoring 468 9.2 Switched-beam Antennas 470 9.3 Cell Splitting 479 9.4 Microcellular Systems 482 9.5 Hierarchical Architectures 487

10 LINK QUALITY MEASUREMENT AND HAND OFF INITIATION 503 10.1 Signal Strength Based Handoff Algorithms 506 10.2 Signal Strength Averaging 508 10.3 Velocity Estimation in Cellular Systems 514 10.4 Velocity Adaptive Handoft' Algorithms 528

10.5 Handoff Analysis 533 10.6 CIR-based Link Quality Measurements 539 10.7 Summary 547

11 CHANNEL ASSIGNMENT TECHNIQUES 555 11.1 Centralized DCA 558 11.2 Decentralized DCA 562 11.3 Fully Decentralized DCA 563 11.4 Hybrid FCAjDCA Schemes 569 11.5 Borrowing Schemes 569 11.6 Directed Retry and Directed Handoff 575 11. 7 Moving Direction Strategies 575 11.8 Reduced Transceiver Coverage 576

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11.9 Handoff Priority 11.10Example DCA Schemes for TDMA Systems 11.11Concluding Remarks

578 578 594

A PROBABILITY AND RANDOM PROCESSES 597 A.I Conditional Probability and Bayes' Theorem 597 A.2 Means, Moments, and Moment Generating Functions 599 A.3 Some Useful Probability Distributions 600 A.4 Upper Bound on the cdfc 607 A.5 Random Processes 611

REFERENCES 629

INDEX 659

PREFACE

With the increasing importance of wireless systems and services in the telecom­munications industry, courses in mobile communications are becoming very popular in many universities. When I first introduced a graduate level course in mobile communications at Georgia Tech in 1992, I had great difficulty in finding a textbook that i) provided an up-to-date treatment of the subject area, and ii) was suitable for instruction. In response to this need, I have com­piled this book from a series of course notes that I developed at Georgia Tech from 1992 to 1995. My goal was to produce a textbook that would provide enough background material for a first-year graduate level course, and have enough advanced material to satisfy the more serious graduate students that would like to pursue research in the area. The book is intended to stress the fundamentals of mobile communications engineering that are important to any mobile system design, as opposed to providing a detailed description of existing and proposed wireless standards. This emphasis on fundamental issues should be of benefit not only to students taking formal instruction, but to practicing engineers who are likely to already have a detailed familiarity with the stan­dards and are seeking to deepen their knowledge of the fundamentals of this important field.

Chapter 1 begins with an overview that is intended to introduce the broad array of issues relating to wireless communications. The remainder of the book is directed toward cellular and PCS issues, but many of the concepts apply to other types of wireless systems as well.

Chapter 2 treats propagation modeling and was inspired by the excellent ref­erence by Jakes. It begins with a summary of propagation models for narrow­band and wide-band channels, and provides a discussion of channel simulation techniques that are useful for radio link analysis. It concludes with a discussion of shadowing and path loss models. Chapter 3 is a related· chapter that pro­vides a detailed treatment of co-channel interference, the primary impairment in high capacity cellular systems.

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Chapter 4 covers the various types of modulation schemes that are used in mobile communication systems along with their spectral characteristics. Chap­ter 5 discusses the performance of digital signal on narrow-band flat fading channels with a variety of receiver structures, and includes a discussion of di­versity techniques.

Chapter 6 provides an extensive treatment of digital signaling on the fading lSI channels that are typical of mid-band land mobile radio systems. The chapter begins with the characterization of lSI channels and goes on to discuss tech­niques for combating lSI based on symbol-by-symbol equalization and sequence estimation.

Chapter 7 covers bandwidth efficient coding techniques. While convolutional and block codes find application in mobile communication systems, I have delib­erately concentrated on the bandwidth efficient class of trellis codes. Included is a detailed discussion on the design and performance analysis of trellis codes for additive white Gaussian noise channels, interleaved flat fading channels, and equalized multi path fading lSI channels.

Chapter 8 is devoted to direct sequence code division multiple access (OS COMA) techniques for cellular radio. The chapter includes a discussion of spreading sequences, RAKE receivers, and error probability approximations for OS COMA systems. It concludes with a discussion of issues relevant to cellular COMA, such as capacity estimation and power control.

Chapters 9 through 11 deal with resource management issues in FOMA and TOMA cellular systems. Chapter 9 considers frequency management schemes. Chapter 10 covers the important problem of link quality evaluation and handoff initiation in cellular systems, while Chapter 11 provides an overview of the various channel assignment techniques that have been proposed for FOMA and TOMA cellular systems.

The book contains far too much detail to be taught in a one-semester course. However, I believe that it can serve as a suitable text in most situations through the appropriate selection of material. My own preference for a one-semester course is to include the following in order: Chapter 1, Chapter 2, Sections 3.1 and 3.2, Chapter 4, Chapter 5, Sections 6.1 to 6.5, Chapter 9, and finally either Chapter 8 or Sections 10.1 to IDA.

I would like to acknowledge all those who have contributed to the preparation of this book. The reviewers Vijay Bhargava at the University of Victoria and Sanjiv Nanda at AT&T Bell Labs were very valuable in early stages of this

Preface Xlll

project. The subsequent review by Upamanyu Madhow of the University ath Illinois and in particular the detailed review by Keith Chugg from the University of Arizona have been highly useful for improving this book. I am grateful to my doctoral students, past and present, who have contributed significantly to this book. The contributions of Wern-Ho Sheen, Khalid Hamied, Mark Austin, and Ming-J u Ho are particularly noteworthy. Finally, I would like to thank BellSouth, GTE Labs, Motorola, Panasonic, Hitachi, Nortel, and NSF, for sustaining my research efforts in mobile communications over the past 6 or 7 years, from which much of the material in this book is drawn.

PRINCIPLES OF MOBILE COMMUNICATION