Direct Broadcast Satellite Communications
An MPEG Enabled Service
Addison-Wesley Wireless Communications Series
A Prentice Hall Title
Upper Saddle River, NJ 07458
http://www.phptr.com
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book and Prentice Hall was aware of a trademark claim, the designations have been printed in initial caps or all caps.
The author and publisher have taken care in the preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the use of the information or programs contained herein.
The publisher offers discounts on this book when ordered in quantity for special sales. For more information, please contact: Corporate Sales Department, Phone: 800-382-3419, Fax: 201-236-7141 E-mail: [email protected], or write: Prentice Hall PTR, Corporate Sales Department, One Lake Street, Upper Saddle River, NJ 07458
Library of Congress Cataloging-in-Publication Data
Mead, Donald C.
Direct broadcast satellite communications : an MPEG enabled service / Donald C. Mead.
p. c.m.—(The Addison-Wesley wireless communications series) Includes bibliographical references and index.
ISBN 0-201-69582-0
1. Direct broadcast satellite television. 2. MPEG (Video coding standard) I. Title. II. Series.
TK6677.M43 1999
621.388'53--dc21
98-56157
CIP
Copyright © 2000 by Prentice Hall PTR
Prentice -Hall, Inc.
Upper Saddle River, NJ 07458
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior consent of the publisher. Printed in the United States of America.
Reprinted with corrections April, 2000.
ISBN 0-201-69582-0
10 9 8 7 6 5 4 3 2
Prentice-Hall International (UK) Limited, London
Prentice-Hall of Australia Pty. Limited, Sydney
Prentice-Hall Canada Inc., Toronto
Prentice-Hall Hispanoamericana, S.A., Mexico
Prentice-Hall of India Private Limited, New Delhi
Prentice-Hall of Japan, Inc., Tokyo
Prentice-Hall (Singapore) Pte. Ltd., Singapore
Editora Prentice-Hall do Brasil, Ltda., Rio de Janeiro
CONTENTS
1 History of Communication Satellites
1.3 The Early Days of Satellite Communications
1.4.2 Attitude Control and Orbital Positioning
1.5 The Early Commercial Geostationary Earth Orbit Satellites: INTELSAT I and II
1.6 The Evolution of Communication Satellites
1.7 The Hughes Direct Broadcast Satellites
2.1 The 1977 World Administrative Radio Council and 1983 Regional Administrative Radio Council
2.2 Federal Communications Commission Licensing
2.3 Recovery and Reallocation of Spectrum
3 An Overview of the DBS Communication System
3.2 Multiple Access and Multiplexing
3.3 Transponder Power and Configuration
3.6 More Services per Orbital Slot
3.8 Degradation Because of Rain
PART TWO THE KEY SUBSYSTEMS AND DESIGN DECISIONS
4 Key Elements of the Radio Frequency Subsystem
4.2 The Shaped Reflector Antenna
4.3 Modulation and Demodulation
4.5 Traveling Wave Tube Amplifier
5.6 Convolutional Codes/Viterbi Decoding
5.7.1 Inner (Convolutional) Code
5.7.4 Performance of (3, 2, 7) Punctured Code and Concatenated Code
6.1 Objectives of a CA System for DBS
6.3 Some Encryption Preliminaries
6.4 Mathematical Preliminaries
6.4.2 Extended Euclid’s Algorithm
6.5.1 The Data Encryption Standard
PART THREE MPEG INTERNATIONAL STANDARDS
Foreword – Dr. Leonardo Chiariglione, MPEG Convenor
7.2.3 Transport Stream Packet Header
7.2.6 Multiplex-wide Operations
7.2.7 Transport Stream System Target Decoder
7.3 Individual Stream Operations (PES Packet Layer)
7.3.3 Relation to Compression Layer
7.4 Program Specific Information
7.4.2 Program Association Table
7.4.4 Conditional Access Table
7.4.5 Network Information Table
7.4.6 Syntax of the Private Section
8.1 The Need for Video Compression
8.4 Structure of MPEG 2 Coded Video
8.5 Detailed MPEG 2 Coding of Pictures
8.6 The Video Decoding Process
8.6.1 Recovering the 8-by-8 Pixel Blocks
8.6.2 Variable Length Decoding
8.7.1 Special Prediction Modes
8.7.2 Field and Frame Prediction
9.1 MPEG Audio Compression Overview
9.2 Description of the Coded Audio Bitstream
9.4 The Audio Decoding Process
10.1 Existing Uplink Facilities
10.2 Constituents of an Uplink Facility
11 Integrated Receiver Decoder
12 Spaceway and the Global Broadcast Service
12.3 The Global Broadcast Service
13 Intelligent Compression: MPEG 4
13.1 Raster and Waveform Emulation versus Symbolic Compression
13.2 MPEG 4: The First Steps Toward Symbolic Compression
13.2.2 The Enabling Technology for Multimedia
13.3.1 Representation of Primitive AVOs
13.3.3 Multiplex and Synchronization of AVOs
13.4 Technical Description of the MPEG 4 Standard
13.4.1 Coding of Audio Objects
13.4.2 Coding of Visual Objects
A Performance Degradation Because of Rain
B QPSK Modulation and Demodulation
G Operators, Mnemonics, Abbreviations
Foreword
The direct broadcast satellites that currently transmit hundreds of video channels into very small dishes are direct descendants of the pioneering SYNCOM satellites developed more than 35 years ago. Although severely limited in power, antenna gain, and bandwidth, the first of these to operate in a geostationary orbit, SYNCOM 3, was nonetheless able to relay a single black-and-white television signal across the Pacific Ocean, transmitting the Tokyo Olympics to the United States in 1964. The extraordinary receiving sensitivity that accomplished this tour de force was achieved by using a very large earth terminal equipped with a liquid-helium-cooled maser, a combination not exactly suited for use in the average home.
During the succeeding years, increases in the transmitter power and antenna gain of the satellites has resulted in more than a millionfold increase in effective radiated power. Improvements in solid-state technology have resulted in uncooled, low-cost ground station receivers nearly as sensitive as the maser. This combination allows the use of the small dishes for television reception, but the limited bandwidth allocated for direct broadcast service limits the number of uncompressed analog television signals to a number too small to create a profitable commercial service.
The final technological advance needed to make a business out of direct broadcast satellites was the development of digital compression techniques and standards. Digital compression multiplies the number of television signals that can be provided by a substantial factor while improving the picture quality. The very low-cost decompressor used in the home equipment required the use of state-of-the-art digital design and manufacturing techniques.
The DBS satellites represent a significant milestone in the development of communications. Don Mead was deeply involved in the creation of geostationary communication satellites, having been responsible for the digital circuits used in SYNCOM’s telemetry and command systems. When Hughes started what became DIRECTV in 1990, Don became our compression guru, creating a laboratory in which the candidate systems could be compared, and serving on the international committee that selected the detailed international standard.
I am sure you will find this book stimulating and instructive because it covers in one place all of the disciplines involved in DBS communications.
Harold A. Rosen
Preface
This book, intended for electronics and communications engineers, describes how all of the individual developments of today’s Direct Broadcast Satellites (DBS) came together to provide an overall communication system capable of delivering more than 200 audio/video services.
The state of the art in communications technology is changing so rapidly that it is difficult for anyone associated with electronic communications to remain current. The developments in compression, in particular, are proceeding at a pace that exceeds even the staggering rate of Moore’s law, which predicts the increasing capabilities of semiconductors that underlie almost all current technologies.
This book starts with a specific communication system, DBS services, and then shows how the MPEG 1 and MPEG 2 standards were used to implement this system. Thus, the book provides the reader with not just an MPEG or communications satellite discussion, but a complete discussion of how the MPEG standards are used to implement a modern satellite broadcast system.
Organization of the Book
The book is divided into the following five parts:
Part One provides an overview of DBS. This includes Chapter 1, History of Communication Satellites; Chapter 2, Regulatory Framework, including international and Federal Communications Commission regulations; and Chapter 3, An Overview of the DBS System.
Part Two describes the key subsystems and design decisions for DBS. These include Chapter 4, Key Elements of the Radio Frequency Subsystem; Chapter 5, Forward Error Correction; and Chapter 6, Conditional Access.
Part Three describes the key elements of the MPEG international standards as they apply to DBS. It includes Chapter 7, MPEG 2 Systems; Chapter 8, MPEG 2 Video Compression; and Chapter 9, MPEG 1 Audio Compression.
Part Four describes the ground subsystems that connect the customer to the satellite: Chapter 10, DBS Uplink Facilities; and Chapter 11, Integrated Receiver Decoder.
Part Five explores some future digital satellite services and technologies. These include Chapter 12, Spaceway and the Global Broadcast Service; and Chapter 13, Intelligent Compression: MPEG 4.
Using This Book
This book is intended for a diverse group of readers, ranging from those who want to obtain a general overview of Direct Broadcast Satellites to those who want to delve deeply into one or all of the technical facets of DBS systems. To accommodate this diversity, sections within the book are annotated by a marginal icon system:
| • | No icon means the material is suitable for all readers. |
|
 |
• | The rectangular satellite icon means the section contains some technically difficult material. |
 |
• | A circular world icon means the section contains serious technical material and probably should only be read by those desiring to gain in-depth knowledge of the subject. |
Certain reference materials, which make the book more self-contained for communications engineers, are included in the appendices. Technical decisions made by DIRECTVTM and the international Digital Video Broadcast standard are used as case studies throughout the book.
Acknowledgments
No book of this nature could possibly be written without the support of a very large number of people. First, all of DBS would have never been possible without Dr. Harold Rosen, my mentor and friend of many years. Dr. George Hrycenko of Hughes Electronics and Suzanne Holdings of the FCC both helped enormously with reference materials for Chapter 2.
Another major contributor to DBS is MPEG, so I want to acknowledge the efforts of all of my MPEG colleagues and, in particular, those of the ‘indispensable man’—the convenor of MPEG, Dr. Leonardo Chiariglione.
Nancy Nilson assisted in the typing of the manuscript. David Dunn-meyer was our faithful proofreader, and my wife, Barbara, took care of many of the administrative efforts. Irv Rabowsky, my long-time colleague, was a constant source of encouragement and help with a number of aspects of the book, and he personally reviewed Chapter 9.
Simon Yates of Thomson Publishing originated the concept of the book, and Karen Gettman, Mary Hart, and Tara Herries of Addison Wesley Longman gave constant encouragement and support during the writing. I also wish to thank the other AWL employees for their support throughout.
Finally, I dedicate the book to the memory of my mother, Pearl Marie Mead, who was my biggest fan. She looked forward to the publication of this book, but her untimely death came before she could enjoy its completion.