Digital Microwave Communication E-Book

George Kizer

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1024

Veröffentlichungsjahr: 2013

Beschreibung

The first book to cover all engineering aspects of microwave communication path design for the digital age Fixed point-to-point microwave systems provide moderate-capacity digital transmission between well-defined locations. Most popular in situations where fiber optics or satellite communication is impractical, it is commonly used for cellular or PCS site interconnectivity where digital connectivity is needed but not economically available from other sources, and in private networks where reliability is most important. Until now, no book has adequately treated all engineering aspects of microwave communications in the digital age. This important new work provides readers with the depth of knowledge necessary for all the system engineering details associated with fixed point-to-point microwave radio path design: the why, what, and how of microwave transmission; design objectives; engineering methodologies; and design philosophy (in the bid, design, and acceptance phase of the project). Written in an easily accessible format, Digital Microwave Communication features an appendix of specialized engineering details and formulas, and offers up chapter coverage of: * A Brief History of Microwave Radio * Microwave Radio Overview * System Components * Hypothetical Reference Circuits * Multipath Fading * Rain Fading * Reflections and Obstructions * Network Reliability Calculations * Regulation of Microwave Radio Networks * Radio Network Performance Objectives * Designing and Operating Microwave Systems * Antennas * Radio Diversity * Ducting and Obstruction Fading * Digital Receiver Interference * Path Performance Calculations Digital Microwave Communication: Engineering Point-to-Point Microwave Systems will be of great interest to engineers and managers who specify, design, or evaluate fixed point-to-point microwave systems associated with communications systems and equipment manufacturers, independent and university research organizations, government agencies, telecommunications services, and other users.

Leseprobe

Table of Contents

series

Title Page

Copyright

Preface

Acknowledgments

About the Author

Chapter 1: A Brief History of Microwave Radio Fixed Point-to-Point (Relay) Communication Systems

1.1 In The Beginning

1.2 Microwave Telecommunications Companies

1.3 Practical Applications

1.4 The Beat Goes On

References

Chapter 2: Regulation of Microwave Radio Transmissions

2.1 Radio Frequency Management

2.2 Testing for Interference

2.3 Radio Paths by FCC Frequency Band in the United States

2.4 Influences in Frequency Allocation and Utilization Policy Within the Western Hemisphere

2.5 FCC Fixed Radio Services

2.6 Site Data Accuracy Requirements

2.7 FCC Antenna Registration System (ASR) Registration Requirements

2.8 Engineering Microwave Paths Near Airports and Heliports

References

Chapter 3: Microwave Radio Overview

3.1 Introduction

3.2 Digital Signaling

3.3 Noise Figure, Noise Factor, Noise Temperature, and Front End Noise

3.4 Digital Pulse Amplitude Modulation (PAM)

3.5 Radio Transmitters and Receivers

3.6 Modulation Format

3.7 QAM Digital Radios

3.8 Channel Equalization

3.9 Channel Coding

3.10 Trellis Coded Modulation (TCM)

3.11 Orthogonal Frequency Division Multiplexing (OFDM)

3.12 Radio Configurations

3.13 Frequency Diversity and Multiline Considerations

3.14 Transmission Latency

3.15 Automatic Transmitter Power Control (ATPC)

3.16 Current Trends

References

Chapter 4: Radio Network Performance Objectives

4.1 Customer Service Objectives

4.2 Maintenance Objectives

4.3 Commissioning Objectives

4.4 Design Objectives

4.5 Differences Between North American and European Radio System Objectives

4.6 North American Telecommunications System Design Objectives

4.7 International Telecommunications System Design Objectives

4.8 Engineering Microwave Paths to Design Objectives

4.9 Accuracy of Path Availability Calculations

4.10 Impact of Flat Multipath Variability

4.11 Impact of Outage Measurement Methodology

4.12 Impact of External Interference

4.13 Conclusion

References

Chapter 5: Radio System Components

5.1 Microwave Signal Transmission Lines

5.2 Antenna Support Structures

5.3 Tower Rigidity and Integrity

5.4 Transmission Line Management

5.5 Antennas

5.6 Near Field

5.7 Fundamental Antenna Limitations

5.8 Propagation

5.9 Radio System Performance as a Function of RadioPath Propagation

5.10 Radio System Performance as a Function of RadioPath Terrain

5.11 Antenna Placement

5.12 Frequency Band Characteristics

5.13 Path Distances

5.A Appendix

References

Chapter 6: Designing and Operating Microwave Systems

6.1 Why Microwave Radio?

6.2 Radio System Design

6.3 Designing Low Frequency Radio Networks

6.4 Designing High Frequency Radio Networks

6.5 Field Measurements

6.6 User Data Interfaces

6.7 Operations and Maintenance

6.8 Maintaining the Network

References

Chapter 7: Hypothetical Reference Circuits

7.1 North American (NA) Availability Objectives

7.2 North American Quality Objectives

7.3 International Objectives

7.4 International Telecommunication Union Quality Objectives

7.5 Error-Performance Relationship Among BER, BBER, and SES

References

Chapter 8: Microwave Antenna Theory

8.1 Common Parameters

8.2 Passive Reflectors

8.3 Circular (Parabolic) Antennas

8.4 Square Flat Panel Antennas

8.5 Regulatory Near Field Power Density Limits

8.6 Practical Near Field Power Calculations

8.7 Near Field Antenna Coupling Loss

8.A Appendix

References

Chapter 9: Multipath Fading

9.1 Flat and Dispersive Fading

9.A Appendix

References

Chapter 10: Microwave Radio Diversity

10.1 Space Diversity

10.2 Dual-Frequency Diversity

10.3 Quad (Space and Frequency) Diversity

10.4 Hybrid Diversity

10.5 Multiline Frequency Diversity

10.6 Crossband Multiline

10.7 Angle Diversity

10.A Appendix

References

Chapter 11: Rain Fading

11.1 Point (Single-Location) Rain Loss (Fade) Estimation

11.2 Path Rain-Fade Estimation

11.3 Point-to-Path Length Conversion Factor

11.4 Single-Location Rain Rate R

11.5 City Rain Rate Data for North America

11.6 New Rain Zones

11.7 Worst-Month Rain Rates

11.8 Point Rain Rate Variability

11.9 Examples of Rain-Loss-Dominated Path Designs

11.10 Conclusions

11.A Appendix

References

Chapter 12: Ducting and Obstruction Fading

12.1 Introduction

12.2 Superrefraction (Ducting)

12.3 Subrefraction (Earth Bulge or Obstruction)

12.4 Minimizing Obstruction Fading

12.5 Obstruction Fading Model

12.6 Obstruction Fading Estimation

12.7 Bell Labs Seasonal Parameter Charts

12.8 Refractivity Data Limitations

12.9 Reviewing the Bell Labs Seasonal Parameter Charts

12.10 Obstruction Fading Parameter Estimation

12.11 Evaluating Path Clearance Criteria

12.A Appendix: North American Refractivity Index Charts

12.B Appendix: Worldwide Obstruction Fading Data

References

Chapter 13: Reflections and Obstructions

13.1 Theoretical Rough Earth Reflection Coefficient

13.2 Scattering from Earth Terrain

13.3 Practical Earth Reflection Coefficient

13.4 Reflection Location

13.5 Smooth Earth Divergence Factor

13.6 Reflections from Objects near a Path

13.7 Fresnel Zones

13.8 Antenna Launch Angle (Transmit or Receive Antenna Takeoff Angle)

13.9 Grazing Angle

13.10 Additional Path Distance

13.11 Estimating the Effect of a Signal Reflected from the Earth

13.12 Flat Earth Obstruction Path Loss

13.13 Smooth Earth Obstruction Loss

13.14 Knife-Edge Obstruction Path Gain

13.15 Rounded-Edge Obstruction Path Gain

13.16 Complex Terrain Obstruction Losses

13.A Appendix

13.A.2 Procedure for Calculating RH and RV

13.A.3 Earth Parameters for Frequencies Between 100 kHz and 1 GHz

13.A.4 Earth Parameters for Frequencies Between 1 GHz and 100 GHz

13.A.5 Comments on Conductivity and Permittivity

13.A.6 Reflection Coefficients

References

Chapter 14: Digital Receiver Interference

14.1 Composite Interference (ΔT/T) Criterion

14.2 Carrier-To-Interference Ratio (C/I) Criterion

14.3 Measuring C/I

14.4 Estimating C/I

14.5 Threshold to Interference (T/I) Criterion

14.6 Why Estimate T/I

14.7 T/I Estimation—Method One

14.8 T/I Estimation—Method Two

14.9 Conclusion

14.A Appendix

14.B Appendix: Receiver Parameters

References

Chapter 15: Network Reliability Calculations

15.1 Hardware Reliability

15.2 System Reliability

15.3 Communication Systems

15.4 Application to Radio Configurations

15.5 Spare Unit Requirements

15.6 BER Estimation

References

Chapter 16: Path Performance Calculations

16.1 Path Loss

16.2 Fade Margin

16.3 Path Performance

16.4 Allowance for Interference

16.5 North American (NA) Path Performance Calculations

16.6 International Telecommunication Union—Radiocommunication Sector (ITU-R) Path Performance Calculations

16.7 Rain Fading and Obstruction Fading (NA and ITU-R)

16.8 Comparing the North American and the ITU-RFlat-Fading Estimates

16.9 Diffraction and Vegetation Attenuation

16.10 Fog Attenuation

16.11 Air Attenuation

16.A Appendix

References

Appendix A: Microwave Formulas and Tables

A.1 General

A.2 Radio Transmission

A.3 Antennas (Far Field)

A.4 Near-Field Power Density

A.5 Antennas (Close Coupled)

A.6 Path Geometry

A.7 Obstruction Loss

A.8 Mapping

A.9 Towers

A.10 Interpolation

Appendix B: Personnel and Equipment Safety Considerations

B.1 General Safety Guidelines

B.2 Equipment Protection

B.3 Equipment Considerations

B.4 Personnel Protective Equipment

B.5 Accident Prevention Signs

B.6 Tower Climbing

B.7 Hand Tools

B.8 Electrical Powered Tools

B.9 Soldering Irons

B.10 Ladders

B.11 Hoisting or Moving Equipment

B.12 Batteries

B.13 Laser Safety Guidelines

B.14 Safe Use of Lasers and LED in Optical Fiber Communication Systems

B.15 Optical Fiber Communication System (OFCS) Service Groups (SG)

B.16 Electrostatic Discharge (ESD)

B.17 Maximum Permissible Microwave Radio RF Exposure

B.18 Protect Other Radio Users [FCC]

B.19 Pause (Prevent all Unplanned Service Events) and ask Yourself (Verizon and AT&T Operations)

B.20 Protect Yourself (Bell System Operations)

B.21 Parting Comment

Index

Copyright © 2013 by The Institute of Electrical and Electronics Engineers, Inc.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey. All rights reserved

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data;

Kizer, George M. (George Maurice), 1945-

Digital microwave communication : engineering point-to-point microwave

systems / George Kizer.

pages cm

ISBN 978-0-470-12534-2 (hardback)

1. Microwave communication systems. 2. Digital communication. I. Title.

TK7876.K548 2013

621.382-dc23

2012048284

Preface

As a young engineer, with only one previous significant project as experience, I was tasked with an overwhelming project: expand the existing South Korean intercity microwave network by 140%. I had a copy of Bob White's Engineering Considerations for Microwave Communications Systems, a couple of volumes of the Lenkurt Demodulator, some Collins Engineering Letters, and a couple of Dick Lane's propagation papers. While these were excellent resources, I was totally unprepared for the job ahead of me. As the old cowboy said, “There were a lot of things they didn't tell me when I signed on for my first cattle drive.” The Korean project was, as you might imagine, rather exciting for a young, enthusiastic engineer. I was introduced to problems I could never have imagined. With the help of many others, I was successful and learned from the experience. However, my technical preparation could have been better.

It has been several years since that first big project. I have done many others and been involved in numerous technical areas related to microwave transmission. However, I continue to be disappointed in the technical information available for the practicing microwave transmission engineer. If I were a new engineer starting on a project, I don't know where I would go to get in-depth technical knowledge on designing fixed point-to-point microwave communication systems. This book is my attempt to remedy the situation.

When I approach a complicated subject for the first time, I like to grasp the overall concepts before diving into the details. I have always admired Dumas and Sands's little blue book, Microwave System Planning. It covers most of the important considerations of microwave path design in less than 140 pages. To provide similar coverage I have organized this book so that the first six chapters address general topics of universal interest. Equations have been kept to a minimum. Figures and tables have been used extensively. The other chapters go into detail on a wide range of topics. The depth of coverage varies. If the topic has been covered adequately in the literature, I attempt to summarize. If the topic has not been covered adequately (e.g., path diversity, dispersive fading, or antenna near field), I go into considerably more detail. Appendix A summarizes the important formulas, and Appendix B covers safety, a critical topic ignored in all other books to date.

This book covers universal design principles. While the agencies performing frequency planning and path design are quite different in North America from those in Europe, the methodologies are similar. I address both North American and European (ITU-R) methods. Several other authors have covered the European (ITU-R) methods; for the first time, this book also covers the North American approach.

To augment the text, Internet resources are also available. Understanding multipath (Chapter 9) is critical to path engineering. After you grasp the concept of a spectrum analyzer (a device that displays received power (on the Y-axis) in a narrow bandwidth around a specific frequency (on the X-axis), take a look at the following videos on YouTube: Digital Radio Multipath Experiment (authored by Eddie Allen)http://youtu.be/AR8Nee-GmTI and Digital Radio Dispersive Fading (authored by Ron Hutchinson)http://youtu.be/ugaz4R3babU. These videos graphically illustrate the received signal distortion caused by multipath propagation.

Wiley has graciously provided a Website for additional data associated with the book: http://booksupport.wiley.com. Enter the ISBN, title, or author's name to access the files. The following folders of information are provided:

Site Index and Book Updates or CorrectionsA detailed index of the site folder contents is provided in one document. The other document describes any updates or corrections that may be discovered.

Computer CodeThis folder contains actual working code for several of the important algorithms described in the book. The code is Microsoft QuickBasic but can be easily converted to other languages.

DataThis folder contains critical data required to implement many of the algorithms discussed in the book.

FiguresThis folder contains detailed color pictures from Chapters 2 and 8. Like the book, they are copyrighted by Wiley.

Public Domain ReferencesThis folder contains resources related to the book's topics. Most of the publications are from the US government. A few are from the National Spectrum Manager's Association. While NSMA documents are not public domain, NSMA has granted the right to distribute their documents freely as long as they are attributed to NSMA.

Rain fading is a complex, difficult subject. Defining high frequency microwave path performance in a rain environment is subject to considerable variability between short-term estimates and actual performance in all cases. Spatial and temporal variations of an order of magnitude or more are common. Rain-related documentation (and climatic data in general) is just too extensive to be easily described or provided. To gain an appreciation for the problem, a good start would be to go to the NOAA Website http://www.nws.noaa.gov/oh/hdsc/currentpf.htm#PF_documents_by_state and download the basic documents found there. For more detailed study, you may need to contact NOAA directly for archival support. Be prepared to be surprised by the challenge of this topic.

My goal is to provide you with the technical background to understand and perform the significant tasks in microwave path design. While no book can make you an expert, I believe this book can significantly enhance your knowledge. As you probably know, success is a combination of ability, preparation, and opportunity. I can't help you with the first and last requirements, but I am confident this book can help you with the preparation.

Acknowledgments

First, I would like to thank Mike and Cathy Newman. Mike suggested this project and was a great supporter and facilitator. Cathy connected me with Wiley. I would also like to thank all my reviewers: Michael Newman (Editorial Coordinator and general whip wielder), Prof. Donald Dudley, Thomas Eckels, Ted Hicks, William Ruck, and last (alphabetically but not technically), Dr. William Rummler. They have given me many great suggestions and corrections. I am in their debt. I especially want to thank the late Dr. Dudley who convinced Wiley this book needed to be published. Also, Dr. Rummler's many technical and ITU-R-related comments and corrections are very much appreciated.

I would also like to thank my editor, Mary Hatcher, production editor, Stephanie Loh, and project manager, Jayashree Saishankar. Moving a concept from text to book is a daunting task; this book was especially demanding. Without their tireless efforts and creative ideas, the project could not have been completed successfully.

I don't want to forget all my associates at Collins Radio, Rockwell International, and Alcatel-Lucent who have contributed do my day to day experiences in microwave radio. I appreciate the friends I have made in many industry associations and government offices I have frequented over the years. I fondly remember the many trips Bob Miller and I made to Washington, D.C. in support of industry regulatory matters. The many customers I have worked with have helped me improve as an engineer; I have enjoyed our mutual experiences. I have many friends throughout the industry but I would like to single out four: Dick Lane has been a longtime associate. I appreciate his knowledge and advice. Eddie Allen is always helpful with path design advice. He is a world-class microwave propagation expert. Of course, it is hard to say too much good about Bill Rummler. He and I have worked together in FCC, FWCC, ITU-R, and TIA matters, and his political and technical capabilities cannot be overstated. Mike Newman has been a longtime associate. He and I started working together 20 years ago when the industry created the FCC Part 101 rules and regulations. This pleasant association has continued ever since.

Although it took me a couple of years to assemble this book, it is based on decades of projects, courses, and presentations. I would like to thank my wife Anne and our children, Amy and Mark, who over the years have put up with the seemingly endless trips and other interruptions that were a constant part of my professional life—and a source of the material for this book.

About the Author

George Kizer has been a microwave engineer for the US Air Force, Collins Radio, Collins Microwave Radio Division of Rockwell International, and Alcatel (now Alcatel-Lucent). He has been a systems engineer, project manager, and product manager for microwave products. From 1991 to 1996, George served as Chairman of the Fixed Point-to-Point Communications Section of TIA in Washington, D.C. During this time, the Section, in coordination with the National Spectrum Management Association, assisted the FCC in the creation of Part 101, the rules that govern licensed microwave communication in the United States. George retired from Alcatel in 2001 and has been a private consultant since then. He lives in Plano, Texas, with his wife Anne and two dogs, Jax and Zoey.

Chapter 1: A Brief History of Microwave Radio Fixed Point-to-Point (Relay) Communication Systems

1.1 In The Beginning

Message relaying and digital transmission seem like recent inventions. Not true—these go way back. The first known message relay system was created by the Egyptian king Sesostris I about 2000 bce. The earliest recorded digital relay transmission by electromagnetic means was around the same time during the Trojan War. King Agamemnon and his troops used signal fires located on mountaintop repeater stations to communicate with each other. The king even used that method to send a message to his wife Clytemnestra. The binary message was either the war was continuing (no fire) or the war was over and he was returning home (fire). The Greek general Polybius, in 300 bce, developed a more complex message set to allow greater information transfer per transmitted symbol. One to five torches were placed on top of each of two walls. Since each wall had five independent states, this allowed 24 Greek characters plus a space to be transmitted with each symbol. This basic concept of using two orthogonal channels (walls then and in-phase and quadrature channels today), with each channel transmitting independent multiple digital states, is the basis of the most modern digital microwave radio systems of today (Bennett and Davey, 1965).

Digital transmission systems continued to advance using the basic concept developed by Polybius. Systems used in the eighteenth and early nineteenth centuries were direct descendents of this approach. In 1794, the French government installed a two-arm optical system, developed by the Chappe brothers 2 years earlier, which could signal 196 characters per transmitted symbol. This system used several intermediate repeater sites to cover the 150 miles between Paris and Lille. In 1795, the British Admiralty began using a 64-character dual multiple shutter optical system. Versions of this semaphore system are in use in the military today (Bennett and Davey, 1965).

Synchronous digital transmission began in 1816 when Ronalds installed an 8-mile system invented by the Chappe brothers. Each end of the system had synchronized clocks and a synchronized spinning wheel that exposed each of the letters of the alphabet as it spun. At the transmitting end, the operator signaled when he or she saw the letter of interest. At the receiving end, a sound (caused by an electric spark) signaled when to record the exposed letter (Bennett and Davey, 1965).

Sömmering proposed a telegraphic system in 1809. Wire (cable)-based electromagnetic telegraphic systems began in the early 1800s with the discovery of the relationship between electricity and magnetism by Aepinus, Oersted, Ampère, Arago, Faraday, Henry, Ohm, Pouillet, and Sturgeon and chemical batteries by Volta, Becquerel, Daniell, Bunsen, and Grove (although a chemical battery from 250 bce was discovered in Baghdad, Iraq, by Konig in 1938). In 1886, Heaviside introduced the concept of impedance as the ratio of voltage divided by current. In 1892, he reported that an electrical circuit had four fundamental properties: resistance, inductance, capacity, and leakage. In 1830, Joseph Henry used an electromagnet to strike a bell over 1 mile of wire. In 1834, Gauss and Weber constructed an electromagnetic telegraph in Gottingen, Germany, connecting the Astronomical Observatory, the Physical Cabinet, and the Magnetic Observatory. In 1838 in England, Edward Davy patented an electrical telegraph system. In 1837, Wheatstone and Cooke patented a telegraph and in 1839 constructed the first commercial electrical telegraph. Samuel Morse, following Henry's approach, teamed with Alfred Vail to improve Morse's original impractical electromagnetic system. The Morse system, unlike earlier visual systems, printed a binary signal (up or down ink traces). Vail devised a sequence of dots and dashes that has become known as Morse code. Morse demonstrated this system in 1838 and patented it in 1840. This design was successfully demonstrated over a 40-mile connection between Baltimore and Washington, DC in 1844. About 1850, Vail invented the mechanical sounder replacing the Morse ink recorder with a device allowing an experienced telegraph operator to receive Morse code by ear of up to 30 words per minute. Morse and Vail formed the Western Union to provide telegram service using their telegraphic system (Carl, 1966; IEEE Communications Society, 2002; Kotel'nikov, 1959; O'Neill, 1985; Salazar-Palma et al., 2011; Sobol, 1984; AT&T Bell Laboratories, 1983).