Fundamentals of Telecommunications. Roger L. Freeman Copyright1999Roger L. Freeman Published by John Wiley & Sons, Inc. ISBNs:0-471-29699-6(Hardback);0-471-22416-2(Electronic) Fundamentals of Telecommunications WILEY SERIES IN TELECOMMUNICATIONS AND SIGNAL PROCESSING John G. Proakis, Editor Northeastern University Introduction to Digital Mobil Communications Yoshihiko Akaiwa Digital Telephony, 2nd Edition John Bellamy Elements of Information Theory Thomas M. Cover and Joy A. Thomas Fundamentals of Telecommunications Roger L. Freeman Practical Data Communications Roger L. Freeman Radio System Design for Telecommunications, 2nd Edition Roger L. Freeman Telecommunication System Engineering, 3rd Edition Roger L. Freeman Telecommunications Transmission Handbook, 4th Edition Roger L. Freeman Introduction to Communications Engineering, 2nd Edition Robert M. Gagliardi Optical Communications, 2nd Edition Robert M. Gagliardi and Sherman Karp Active Noise Control Systems: Algorithms and DSP Implementations Sen M. Kuo and Dennis R. Morgan Mobile Communications Design Fundamentals, 2nd Edition William C. Y. Lee Expert System Applications for Telecommunications Jay Liebowitz Digital Signal Estimation Robert J. Mammone, Editor Digital Communication Receivers: Synchronization, Channel Estimation, and Signal Processing Heinrich Meyr, Marc Moeneclaey, and Stefan A. Fechtel Synchronization in Digital Communications, Volume I Heinrich Meyr and Gerd Ascheid Business Earth Stations for Telecommunications Walter L. Morgan and Denis Rouffet Wireless Information Networks Kaveh Pahlavan and Allen H. Levesque Satellite Communications: The First Quarter Century of Service David W. E. Rees Fundamentals of Telecommunication Networks Tarek N. Saadawi, Mostafa Ammar, with Ahmed El Hakeem Meteor Burst Communications: Theory and Practice Donald L. Schilling, Editor Vector Space Projections: A Numerical Approach to Signal and Image Processing, Neural Nets, and Optics Henry Stark and Yongyi Yang Signaling in Telecommunication Networks John G. van Bosse Telecommunication Circuit Design Patrick D. van der Puije Worldwide Telecommunications Guide for the Business Manager Walter H. Vignault Fundamentals of Telecommunications Roger L. Freeman A Wiley-Interscience Publication JOHN WILEY & SONS, INC. New York • Chichester • Weinheim • Brisbane • Singapore • Toronto Designations used by companies to distinguish their products are often claimed as trademarks. In all instances where John Wiley & Sons, Inc., is aware of a claim, the product names appear in initial capital or ALL CAPITAL LETTERS. Readers, however, should contact the appropriate companies for more complete information regarding trademarks and registration. Copyright1999by Roger L. Freeman. All rights reserved. Published by John Wiley & Sons, Inc. 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To Paquita CONTENTS Preface xxi Chapter 1 Introductory Concepts 1 1.1 What Is Telecommunication? 1 1.2 Telecommunication Will Touch Everybody 1 1.3 Introductory Topics in Telecommunications 2 1.3.1 End-Users, Nodes, and Connectivities 2 1.3.2 Telephone Numbering and Routing 6 1.3.3 Use of Tandem Switches in a Local Area Connectivity 7 1.3.4 Busy Hour and Grade of Service 7 1.3.5 Simplex, Half-Duplex, and Full Duplex 9 1.3.6 One-Way and Two-Way Circuits 9 1.3.7 Network Topologies 10 1.3.8 Variations in Traffic Flow 14 1.4 Quality of Service 15 1.5 Standardization in Telecommunications 16 1.6 Organization of the PSTN in the United States 17 1.6.1 Points of Presence 17 Review Exercises 18 References 19 Chapter 2 Signals Convey Intelligence 21 2.1 Objective 21 2.2 Signals in Everyday Life 21 2.3 Basic Concepts of Electricity for Communications 22 2.3.1 Early Sources of Electrical Current 22 2.3.2 Electrical Telegraph: An Early Form of Long- Distance Communications 23 2.3.3 What Is Frequency? 25 2.4 Electrical Signals 30 2.4.1 Introduction to Transmission 30 2.4.2 Modulation 31 2.4.3 Binary Digital Signals 33 vii viii CONTENTS 2.5 Introduction to Transporting Electrical Signals 34 2.5.1 Wire Pair 34 2.5.2 Coaxial Cable Transmission 37 2.5.3 Fiber Optic Cable 38 2.5.4 Radio Transmission 38 Review Exercises 40 References 41 Chapter 3 Quality of Service and Telecommunication Impairments 43 3.1 Objective 43 3.2 Quality of Service: Voice, Data, and Image 43 3.2.1 Introduction to Signal-to-Noise Ratio 43 3.2.2 Voice Transmission 44 3.2.3 Data Circuits 46 3.2.4 Video (Television) 47 3.3 Three Basic Impairments and How They Affect the End-User 47 3.3.1 Amplitude Distortion 47 3.3.2 Phase Distortion 48 3.3.3 Noise 50 3.4 Level 53 3.4.1 Typical Levels 53 3.5 Echo and Singing 54 Review Exercises 54 References 55 Chapter 4 Transmission and Switching: Cornerstones of a Network 57 4.1 Transmission and Switching Defined 57 4.2 Traffic Intensity Defines the Size of Switches and the Capacity of Transmission Links 57 4.2.1 Traffic Studies 57 4.2.2 Discussion of the Erlang and Poisson Traffic Formulas 63 4.2.3 Waiting Systems (Queueing) 66 4.2.4 Dimensioning and Efficiency 66 4.2.5 Quantifying Data Traffic 71 4.3 Introduction to Switching 71 4.3.1 Basic Switching Requirements 71 4.3.2 Concentration and Expansion 72 4.3.3 Essential Functions of a Local Switch 73 4.3.4 Some Introductory Switching Concepts 75 4.3.5 Early Automatic Switching Systems 75 4.3.6 Common Control (Hard-Wired) 77 4.3.7 Stored Program Control 77 4.3.8 Concentrators and Remote Switching 79 CONTENTS ix 4.4 Some Essential Concepts in Transmission 80 4.4.1 Introduction 80 4.4.2 Two-Wire and Four-Wire Transmission 80 4.5 Introduction to Multiplexing 83 4.5.1 Definition 83 4.5.2 Frequency Division Multiplex 84 4.5.3 Pilot Tones 87 4.5.4 Comments on the Employment and Disadvantages of FDM Systems 89 Review Exercises 90 References 92 Chapter 5 Transmission Aspects of Voice Telephony 93 5.1 Objective 93 5.2 Definition of the Voice Channel 93 5.2.1 Human Voice 94 5.3 Operation of a Telephone Subset 94 5.3.1 Subset Mouthpiece or Transmitter 97 5.3.2 Telephone Earpiece or Receiver 97 5.4 Subscriber Loop Design 97 5.4.1 Basic Design Considerations 97 5.4.2 Subscriber Loop Length Limits 98 5.4.3 Designing a Subscriber Loop 99 5.4.4 Extending the Subscriber Loop 101 5.4.5 “Cookbook” Design Methods for Subscriber Loops 102 5.4.6 Current North American Loop Design Rules 105 5.5 Design of Local Area Wire-Pair Trunks (Junctions) 106 5.5.1 Introduction 106 5.5.2 Inductive Loading of Wire-Pair Trunks (Junctions) 106 5.5.3 Local Trunk (Junction) Design Considerations 107 5.6 VF Repeaters (Amplifiers) 108 Review Exercises 108 References 109 Chapter 6 Digital Networks 111 6.1 Introduction to Digital Transmission 111 6.1.1 Two Different PCM Standards 112 6.2 Basis of Pulse Code Modulation 112 6.2.1 Sampling 112 6.2.2 Quantization 113 6.2.3 Coding 117 6.3 PCM System Operation 122 6.4 Line Code 123 x CONTENTS 6.5 Signal-to-Gaussian-Noise Ratio on PCM Repeatered Lines 124 6.6 Regenerative Repeaters 125 6.7 PCM System Enhancements 126 6.7.1 Enhancements to DS1 126 6.7.2 Enhancements to E1 126 6.8 Higher-Order PCM Multiplex Systems 127 6.8.1 Introduction 127 6.8.2 Stuffing and Justification 127 6.8.3 North American Higher-Level Multiplex 127 6.8.4 European E1 Digital Hierarchy 129 6.9 Long-Distance PCM Transmission 131 6.9.1 Transmission Limitations 131 6.9.2 Jitter and Wander 131 6.9.3 Distortion 132 6.9.4 Thermal Noise 132 6.9.5 Crosstalk 133 6.10 Digital Loop Carrier 133 6.10.1 New Versions of DSL 133 6.11 Digital Switching 133 6.11.1 Advantages and Issues of Digital Switching 133 6.11.2 Approaches to PCM Switching 134 6.11.3 Review of Some Digital Switching Concepts 140 6.12 Digital Network 142 6.12.1 Introduction 142 6.12.2 Technical Requirements of the Digital Network 143 6.12.3 Digital Network Performance Requirements 148 Review Exercises 150 References 152 Chapter 7 Signaling 155 7.1 What Is the Purpose of Signaling? 155 7.2 Defining the Functional Areas 155 7.2.1 Supervisory Signaling 155 7.2.2 Address Signaling 156 7.2.3 Call Progress—Audible-Visual 156 7.3 Signaling Techniques 156 7.3.1 Conveying Signaling Information 156 7.3.2 Evolution of Signaling 157 7.3.3 Subscriber Call Progress Tones and Push- Button Codes (North America) 164 7.4 Compelled Signaling 164 7.5 Concepts of Link-by-Link and End-to-End Signaling 166 7.6 Effects of Numbering on Signaling 167 7.7 Associated and Disassociated Channel Signaling 168 7.8 Signaling in the Subscriber Loop 168 CONTENTS xi 7.8.1 Background and Purpose 168 7.9 Metallic Trunk Signaling 171 7.9.1 Basic Loop Signaling 171 7.9.2 Reverse-Battery Signaling 172 Review Exercises 173 References 173 Chapter 8 Local and Long-Distance Networks 175 8.1 Objective 175 8.2 Makeup of the PSTN 175 8.2.1 Evolving Local Network 175 8.2.2 What Affects Local Network Design? 176 8.3 Design of Long-Distance Networks 179 8.3.1 Introduction 179 8.3.2 Three Design Steps 179 8.3.3 Link Limitation 180 8.3.4 Numbering Plan Areas 182 8.3.5 Exchange Location 182 8.3.6 Hierarchy 182 8.3.7 Network Design Procedures 183 8.4 Traffic Routing in a National Network 188 8.4.1 New Routing Techniques 188 8.4.2 Logic of Routing 189 8.4.3 Call-Control Procedures 190 8.4.4 Applications 191 8.5 Transmission Factors in Long-Distance Telephony 194 8.5.1 Introduction 194 8.5.2 Echo 195 8.5.3 Singing 195 8.5.4 Causes of Echo and Singing 195 8.5.5 Transmission Design to Control Echo and Singing 198 8.5.6 Introduction to Transmission-Loss Engineering 198 8.5.7 Loss Plan for Digital Networks (United States) 200 Review Exercises 201 References 202 Chapter 9 Concepts in Transmission Transport 203 9.1 Objective 203 9.2 Radio Systems 204 9.2.1 Scope 204 9.2.2 Introduction to Radio Transmission 204 9.2.3 Line-of-Sight Microwave 205 9.2.4 Fades, Fading and Fade Margins 221 9.2.5 Diversity and Hot-Standby 223 9.2.6 Frequency Planning and Frequency Assignment 225