DOCSLIB.ORG

Module 9. Communications

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Module 9. Communications Manual TABLE OF CONTENTS Module 9. TABLE OF CONTENTS MODULE 9. COMMUNICATIONS TABLE OF CONTENTS 9.1 INTRODUCTION ............................................ 9-3 MODULE OBJECTIVES ............................................. 9-4 MODULE SCOPE ................................................... 9-4 9.2 DECISION PROCESS ....................................... 9-4 PROBLEM IDENTIFICATION ........................................ 9-5 IDENTIFICATION OF PARTNERS AND CONSENSUS BUILDING ........... 9-8 ESTABLISH SYSTEM GOALS AND OBJECTIVES ....................... 9-9 ESTABLISH PERFORMANCE CRITERIA ............................... 9-9 FUNCTIONAL REQUIREMENTS ..................................... 9-10 DEFINE FUNCTIONAL RELATIONSHIPS, DATA REQUIREMENTS, AND INFORMATION FLOWS .................................... 9-12 Logical ........................................................ 9-12 Physical ....................................................... 9-12 Central ..................................................... 9-14 Distributed .................................................. 9-16 Trunking ................................................... 9-16 Backbone ................................................... 9-16 Multimedia .................................................. 9-18 IDENTIFY AND SCREEN TECHNOLOGIES ............................ 9-18 IMPLEMENTATION ............................................... 9-23 National ITS Standards ........................................... 9-23 Installation ..................................................... 9-26 9.3 TECHNIQUES AND TECHNOLOGIES ................... 9-26 LAND-LINES ..................................................... 9-26 Twisted-Wire Pairs ............................................... 9-27 Coaxial Cable ................................................... 9-31 Fiber Optic ..................................................... 9-35 WIRELESS ....................................................... 9-39 Area Radio Network ............................................. 9-39 Microwave ..................................................... 9-42 Spread Spectrum Radio ........................................... 9-43 Cellular Radio .................................................. 9-45 Packet Radio ................................................... 9-48 Satellite Transmission ............................................. 9-50 9.4 LESSONS LEARNED ....................................... 9-51 DESIGN PRINCIPLES .............................................. 9-51 OWNED VERSUS LEASED COMMUNICATIONS ....................... 9-53 9-1 Manual TABLE OF CONTENTS Module 9. TABLE OF CONTENTS NTCIP ........................................................... 9-56 SHARED RESOURCE PROJECTS .................................... 9-59 TRANSIENT PROTECTION ......................................... 9-63 COMMUNICATIONS WITHIN THE CONTROL CENTER ................. 9-64 9.5 REFERENCES .............................................. 9-65 9-2 Manual TABLE OF CONTENTS Module 9. TABLE OF CONTENTS MODULE 9. COMMUNICATIONS Figure 9-1. Fiber Optic Cable Installation in Fort Worth, TX. 9.1 INTRODUCTION of information to be transferred from the field components and the control center: (1) The communications subsystem is one of the most critical and expensive elements of a • Commands to the various field freeway management system. The function components. of the communications system is to link the devices in the field with the operating • Data from the system detectors and personnel in the control center. It is the sensors. backbone of the entire freeway management system because it allows the following types • Status checks of field equipment to detect malfunctions. 9-3 Manual TABLE OF CONTENTS Module 9. TABLE OF CONTENTS Typically, the communications system MODULE OBJECTIVES accounts for approximately 25 percent of the total capital costs associated with a freeway The objectives of this module are as follows: management system. Failure to plan, design, and properly maintain the communications • To outline the process that can be system guarantees the entire freeway followed in planning and designing a management system will have problems in new freeway management system or achieving its operational goals and updating or modifying an existing objectives. Poor planning and installation of freeway management system. the communication system can also result in high operating and maintenance costs. To • To highlight the different types of avoid problems with the communications communication technologies that are system, system planners, designers, and commonly used in a freeway operators must be familiar with existing and management system. emerging communication technologies and system architectures. • To provide insight into the issues associated with planning, designing, Three general types of communications constructing, operating, and maintaining systems are used in a freeway management a communications system in a freeway system: management system. • A communications system allowing the MODULE SCOPE transfer of surveillance data and control commands between field devices and the The focus of this module is on the decision control center. process for planning, designing, and selecting a communications system for a • A communications system allowing the freeway management system. It is intended computers within the control center to to help system designers and traffic transfer data and displays between each engineers make informed decisions about other. communications systems. It is not intended to provide detailed information about the • A communications system allowing the operation of different communications operators in the control center to systems or technologies. For more detailed exchange data and information with information about the different other operators and field personnel communications technologies, the reader outside the control center. should consult the Communications Handbook for Traffic Control Devices and This module focuses on the first type of the Traffic Control Systems Handbook.(1,2) communications system (i.e., the communications system needed to transfer 9.2 DECISION PROCESS surveillance information and data, and control commands between the field devices As with the planning and design of the other and the control center). For information on functional elements of a freeway the other types of communications systems, management system, a systems engineering the reader is referred to Module 10. approach can also be applied to the planning, design, and use of a communications system 9-4 Manual TABLE OF CONTENTS Module 9. TABLE OF CONTENTS for a freeway management system. An • The relative importance of the overview of the systems engineering information and how a loss of approach is presented in Module 2. The communication from each device would information in this section highlights some affect the overall operation of the important issues that need to be discussed, system. evaluated, and decided upon as part of the systems engineering process. The user is Table 9-1 summarizes some physical, encouraged to consult other reference institutional, and other issues that might materials, such as the Communications affect the planning and design of the Handbook for Traffic Control Systems for a communications system for a freeway detailed discussion of the technical aspects management system. associated with planning and designing a communications system for traffic control One question that must be addressed in applications. (1) planning and designing a communications system is the type of data that will be PROBLEM IDENTIFICATION transmitted over the communications medium: voice, data, video, or a The first step in planning and designing a combination of all three. A communications communications system for a freeway medium is the pathway over which a signal management system is to identify the is transmitted (i.e., twisted wire pair, coaxial physical, institutional, and other factors that cable, fiber, radio, etc.). “Voice” is the might affect the design of the chosen term for audio signals, since the communications system. System designers impetus for modern communications systems and planners need to collect information on was the need to transmit vocal messages the following attributes and characteristics over the telephone. While some freeway about each of the other elements and management applications, such as Highway subsystems that will be supported by the Advisory Radio, still depend on voice communications system. The types of communications, data is the most general information that should be gathered include type of information transmitted in a the following: communications system in a freeway management system. Digital data is the most • The type of data that will be transmitted common form of transmitted information in by each field device. today’s communications systems. With digital data, information is represented by a • The content and format of the data combination of bits, where a bit can assume transmitted. one of only two states: “0” or “1.” Digital data can be physically transmitted as voltage • How much processing of data will occur differences between pairs of wires, light in the field devices and where this intensities in an optical fiber, frequencies in processing will occur. a transmission line, or phases of a radio wave. Video is animated imagery and • The total number of field devices and represents the most demanding form of data where they will be situated. transmission.
Load more

Recommended publications
  • The Twisted-Pair Telephone Transmission Line
    High Frequency Design From November 2002 High Frequency Electronics Copyright © 2002, Summit Technical Media, LLC TRANSMISSION LINES The Twisted-Pair Telephone Transmission Line By Richard LAO Sumida America Technologies elephone line is a This article reviews the prin- balanced twisted- ciples of operation and Tpair transmission measurement methods for line, and like any electro- twisted pair (balanced) magnetic transmission transmission lines common- line, its characteristic ly used for xDSL and ether- impedance Z0 can be cal- net computer networking culated from manufactur- ers’ data and measured on an instrument such as the Agilent 4395A (formerly Hewlett-Packard HP4395A) net- Figure 1. Lumped element model of a trans- work analyzer. For lowest bit-error-rate mission line. (BER), central office and customer premise equipment should have analog front-end cir- cuitry that matches the telephone line • Category 3: BWMAX <16 MHz. Intended for impedance. This article contains a brief math- older networks and telephone systems in ematical derivation and and a computer pro- which performance over frequency is not gram to generate a graph of characteristic especially important. Used for voice, digital impedance as a function of frequency. voice, older ethernet 10Base-T and commer- Twisted-pair line for telephone and LAN cial customer premise wiring. The market applications is typically fashioned from #24 currently favors CAT5 installations instead. AWG or #26 AWG stranded copper wire and • Category 4: BWMAX <20 MHz. Not much will be in one of several “categories.” The used. Similar to CAT5 with only one-fifth Electronic Industries Association (EIA) and the bandwidth. the Telecommunications Industry Association • Category 5: BWMAX <100 MHz.
    [Show full text]
  • Transmission Media Transmission Media Are Actually Located Below the Physical Layer and Are Directly Controlled by the Physical Layer
    SYBScIT /Sem III / Computer networks UNIT II • MULTIPLEXING Multiplexing is the set of technique that allow the simultaneous transmission of multiple signals across a single data link.In a multiplexed system, n lines share the bandwidth of one link. The lines on the left direct their transmission streams to a multiplexer (MUX), which combines them into a single stream (many-to-one). At the receiving end, that stream is fed into a demultiplexer (DEMUX), which separates the stream back into its component transmissions (one- to-many) and directs them to their corresponding lines. In the figure, the word link refers to the physical path. The word channel refers to the portion of a link that carries a transmission between a given pair of lines. One link can have many (n) channels. There are three basic multiplexing techniques: frequency-division multiplexing, wavelength- division multiplexing, and time-division multiplexing. • Frequency-Division Multiplexing(FDM) Frequency-division multiplexing (FDM) is an analog technique that can be applied when the bandwidth of a link (in hertz) is greater than the combined bandwidths of the signals to be transmitted. In FDM, signals generated by each sending device modulate different carrier frequencies. These modulated signals are then combined into a single composite signal that can be transported by the link. Carrier frequencies are separated by sufficient bandwidth to accommodate the modulated signal. These bandwidth ranges are the channels through which the various signals travel chapter SYBScIT /Sem III / Computer networks Channels can be separated by strips of unused bandwidth—guard bands—to prevent signals from overlapping. FDM is an analog multiplexing technique that combines analog signals.
    [Show full text]
  • Catv Cabling System
    NYULMC AMBULATORY CARE CENTER – FIT-OUT PHASE 1 Perkins & Will Architects PC 222 E 41st ST, NYC Project: 032698.000 Issued for GMP March 15, 2017 SECTION 27 41 33 CATV CABLING PART 1 - GENERAL 1.1 SYSTEM DESCRIPTION A. Furnish and install a complete and fully operational Television Signal Distribution System capable of delivering up to 158 video channels (6 MHz NTSC Channels containing NTSC, ATSC and QAM modulated programs) and IP Video over an installed Category 6A unshielded twisted pair cable system. The System shall utilize a cable plant comprised of a TIA/EIA 568 compliant horizontal distribution cable system and a coaxial and/or single mode fiber backbone system. The System shall employ Active Automatic Gain Control Electronics to adjust the video signal levels to each TV and shall be capable of supporting up to 14,000 connected devices. The System shall support bi-directional RF transmission for backbone interconnections. Include amplifiers, power supplies, cables, outlets, attenuators, hubs, baluns, adaptors, transceivers, and other parts necessary for the reception and distribution of the local CATV signals. Back-feed existing campus system. (CAT 5e is acceptable to 117 channels) B. Distribute cable channels to TV outlets to permit simple connection of EIA standard Analog/Digital television receivers. C. Deliver at outlets monochrome and NTSC color television signals without introducing noticeable effect on picture and color fidelity or sound. Signal levels and performance shall meet or exceed the minimums specified in Part 76 of the FCC Rules and Regulations D. Provide reception quality at each outlet equal to or better than that received in the area with individual antennas.
    [Show full text]
  • Spread Spectrum and Wi-Fi Basics Syed Masud Mahmud, Ph.D
    Spread Spectrum and Wi-Fi Basics Syed Masud Mahmud, Ph.D. Electrical and Computer Engineering Dept. Wayne State University Detroit MI 48202 Spread Spectrum and Wi-Fi Basics by Syed M. Mahmud 1 Spread Spectrum Spread Spectrum techniques are used to deliberately spread the frequency domain of a signal from its narrow band domain. These techniques are used for a variety of reasons such as: establishment of secure communications, increasing resistance to natural interference and jamming Spread Spectrum and Wi-Fi Basics by Syed M. Mahmud 2 Spread Spectrum Techniques Frequency Hopping Spread Spectrum (FHSS) Direct -Sequence Spread Spectrum (DSSS) Orthogonal Frequency-Division Multiplexing (OFDM) Spread Spectrum and Wi-Fi Basics by Syed M. Mahmud 3 The FHSS Technology FHSS is a method of transmitting signals by rapidly switching channels, using a pseudorandom sequence known to both the transmitter and receiver. FHSS offers three main advantages over a fixed- frequency transmission: Resistant to narrowband interference. Difficult to intercept. An eavesdropper would only be able to intercept the transmission if they knew the pseudorandom sequence. Can share a frequency band with many types of conventional transmissions with minimal interference. Spread Spectrum and Wi-Fi Basics by Syed M. Mahmud 4 The FHSS Technology If the hop sequence of two transmitters are different and never transmit the same frequency at the same time, then there will be no interference among them. A hopping code determines the frequencies the radio will transmit and in which order. A set of hopping codes that never use the same frequencies at the same time are considered orthogonal .
    [Show full text]
  • Radio Communications in the Digital Age
    Radio Communications In the Digital Age Volume 1 HF TECHNOLOGY Edition 2 First Edition: September 1996 Second Edition: October 2005 © Harris Corporation 2005 All rights reserved Library of Congress Catalog Card Number: 96-94476 Harris Corporation, RF Communications Division Radio Communications in the Digital Age Volume One: HF Technology, Edition 2 Printed in USA © 10/05 R.O. 10K B1006A All Harris RF Communications products and systems included herein are registered trademarks of the Harris Corporation. TABLE OF CONTENTS INTRODUCTION...............................................................................1 CHAPTER 1 PRINCIPLES OF RADIO COMMUNICATIONS .....................................6 CHAPTER 2 THE IONOSPHERE AND HF RADIO PROPAGATION..........................16 CHAPTER 3 ELEMENTS IN AN HF RADIO ..........................................................24 CHAPTER 4 NOISE AND INTERFERENCE............................................................36 CHAPTER 5 HF MODEMS .................................................................................40 CHAPTER 6 AUTOMATIC LINK ESTABLISHMENT (ALE) TECHNOLOGY...............48 CHAPTER 7 DIGITAL VOICE ..............................................................................55 CHAPTER 8 DATA SYSTEMS .............................................................................59 CHAPTER 9 SECURING COMMUNICATIONS.....................................................71 CHAPTER 10 FUTURE DIRECTIONS .....................................................................77 APPENDIX A STANDARDS
    [Show full text]
  • A Guide to Radio Communications Standards for Emergency Responders
    A GUIDE TO RADIO COMMUNICATIONS STANDARDS FOR EMERGENCY RESPONDERS Prepared Under United Nations Development Programme (UNDP) and the European Commission Humanitarian Office (ECHO) Through the Disaster Preparedness Programme (DIPECHO) Regional Initiative in Disaster Risk Reduction March, 2010 Maputo - Mozambique GUIDE TO RADIO COMMUNICATIONS STANDARDS FOR EMERGENCY RESPONDERS GUIDE TO RADIO COMMUNICATIONS STANDARDS FOR EMERGENCY RESPONDERS Table of Contents Introductory Remarks and Acknowledgments 5 Communication Operations and Procedures 6 1. Communications in Emergencies ...................................6 The Role of the Radio Telephone Operator (RTO)...........................7 Description of Duties ..............................................................................7 Radio Operator Logs................................................................................9 Radio Logs..................................................................................................9 Programming Radios............................................................................10 Care of Equipment and Operator Maintenance...........................10 Solar Panels..............................................................................................10 Types of Radios.......................................................................................11 The HF Digital E-mail.............................................................................12 Improved Communication Technologies......................................12
    [Show full text]
  • Digital Television Systems
    This page intentionally left blank Digital Television Systems Digital television is a multibillion-dollar industry with commercial systems now being deployed worldwide. In this concise yet detailed guide, you will learn about the standards that apply to fixed-line and mobile digital television, as well as the underlying principles involved, such as signal analysis, modulation techniques, and source and channel coding. The digital television standards, including the MPEG family, ATSC, DVB, ISDTV, DTMB, and ISDB, are presented toaid understanding ofnew systems in the market and reveal the variations between different systems used throughout the world. Discussions of source and channel coding then provide the essential knowledge needed for designing reliable new systems.Throughout the book the theory is supported by over 200 figures and tables, whilst an extensive glossary defines practical terminology.Additional background features, including Fourier analysis, probability and stochastic processes, tables of Fourier and Hilbert transforms, and radiofrequency tables, are presented in the book’s useful appendices. This is an ideal reference for practitioners in the field of digital television. It will alsoappeal tograduate students and researchers in electrical engineering and computer science, and can be used as a textbook for graduate courses on digital television systems. Marcelo S. Alencar is Chair Professor in the Department of Electrical Engineering, Federal University of Campina Grande, Brazil. With over 29 years of teaching and research experience, he has published eight technical books and more than 200 scientific papers. He is Founder and President of the Institute for Advanced Studies in Communications (Iecom) and has consulted for several companies and R&D agencies.
    [Show full text]
  • HD Television on Cat 5/6 Cable Cable TV on Cat 5/6 Cable
    HD Television on Cat 5/6 Cable Cable TV on Cat 5/6 Cable Innovative Technology .... Exceptional Quality! The Lynx® Television Network Distributes up to 640 digital Increases flexibility for moves, adds channels on Cat 5 or Cat 6 cable and changes Excellent for cable TV, SMATV, or Improves reliability off-air television distribution Creates a technology bridge to Simplifies cabling requirements Internet TV and IPTV The Lynx Television Network simultaneously simplifies installation, standardizes the wiring, delivers up to 210 HDTV channels, 640 and reduces maintenance requirements. standard digital channels, or 134 analog channels on Cat 5 or Cat 6 cable. Frequency The Lynx Network increases system flexibility capabilities are 5 MHz to 860 MHz. because moves, adds, and changes are easy with Cat5/6 cable. A Lynx hub in the wiring closet converts an unbalanced coaxial signal into eight or A homerun wiring design improves reliability sixteen balanced signals transmitted on because there are no taps or splitters between twisted pair cables. At the point of use a the distribution hub and the TV. wallplate F or single port converter changes the signal back to coaxial form. The Lynx Network also provides a “technology bridge” to Internet TV and IPTV by setting up the cabling that these technologies use. A patented RF balun is the centerpiece of the Lynx design. A pair of send / receive baluns delivers a clean RF signal to each TV (on pair four). The baluns use an RF technology that delivers HD, digital, and analog channels on network cables without using any bandwidth Wallplate F Single port converter on the network itself.
    [Show full text]
  • Introduction to Digital Subscriber's Line (DSL) Chapter 2 Telephone
    Introduction to Digital Subscriber’s Line (DSL) Professor Fu Li, Ph.D., P.E. © Chapter 2 Telephone Infrastructure · Telephone line dates back to Bell in 1875 · Digital Transmission technology using complex algorithm based on DSP and VLSI to compensate impairments common to phone lines. · Phone line carries the single voice signal with 3.4 KHz bandwidth, DSL conveys 100 Compressed voice signals or a video signals. 1 · 15% phones require upgrade activities. · Phone company spent approximately 1 trillion US dollars to construct lines; · 700 millions are in service in 1997, 900 millions by 2001. · Most lines will support 1 Mb/s for DSL and many will support well above 1Mb/s data rate. Typical Voice Network 2 THE ACCESS NETWORK • DSL is really an access technology, and the associated DSL equipment is deployed in the local access network. • The access network consists of the local loops and associated equipment that connects the service user location to the central office. • This network typically consists of cable bundles carrying thousands of twisted-wire pairs to feeder distribution interfaces (FDIs). Two primary ways traditionally to deal with long loops: • 1.Use loading coils to modify the electrical characteristics of the local loop, allowing better quality voice-frequency transmission over extended distances (typically greater than 18,000 feet). • Loading coils are not compatible with the higher frequency attributes of DSL transmissions and they must be removed before DSL-based services can be provisioned. 3 Two primary ways traditionally to deal with long loops • 2. Set up remote terminals where the signals could be terminated at an intermediate point, aggregated and backhauled to the central office.
    [Show full text]
  • Analysis of FHSS-CDMA with QAM-64 Over AWGN and Fading Channels Prashanth G S1
    International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 04 Issue: 08 | Aug -2017 www.irjet.net p-ISSN: 2395-0072 Analysis of FHSS-CDMA with QAM-64 over AWGN and Fading Channels Prashanth G S1 Assistant Professor, Dept. of ECE, JNNCE, Shivamogga, Karnataka, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract – CDMA is a type of channel access method in huge amount of power which result in implementation of which users using the same channel will use the same extra hardware to normalize the power requirement. [2] frequency band and also can access the channel at the same Frequency-hopping spread spectrum (FHSS) is a time. Using CDMA, more users can be allocated in the channel method of transmitting radio signals by rapidly compared to TDMA and FDMA. CDMA can be achieved using switching a carrier among many frequency channels Direct sequence spread spectrum(DSSS) and Frequency using a pseudo random sequence known to both transmitter hopping spread spectrum(FHSS). FHSS-CDMA consumes less and receiver. FHSS-CDMA consumes less power compared to power compared to DSSS-CDMA. High data rate modulation DSSS-CDMA. High data rate modulation schemes are used schemes are used along with FHSS-CDMA to deliver high along with FHSS-CDMA to deliver high quality multimedia quality multimedia content. High data rate modulation content. QAM-64 modulation technique as good bandwidth techniques have good bandwidth efficiency in FHSS-CDMA. In efficiency with wideband FHSS-CDMA. Author in [4], wireless communication, QAM is one of the most commonly discusses about broadband wireless access techniques. used modulation technique. Due to noise and interference, For 4G systems data rates up to 100 Mbps will be high data rate modulation techniques are prone to errors.
    [Show full text]
  • Digital Subscriber Lines and Cable Modems Digital Subscriber Lines and Cable Modems
    Digital Subscriber Lines and Cable Modems Digital Subscriber Lines and Cable Modems Paul Sabatino, [email protected] This paper details the impact of new advances in residential broadband networking, including ADSL, HDSL, VDSL, RADSL, cable modems. History as well as future trends of these technologies are also addressed. OtherReports on Recent Advances in Networking Back to Raj Jain's Home Page Table of Contents ● 1. Introduction ● 2. DSL Technologies ❍ 2.1 ADSL ■ 2.1.1 Competing Standards ■ 2.1.2 Trends ❍ 2.2 HDSL ❍ 2.3 SDSL ❍ 2.4 VDSL ❍ 2.5 RADSL ❍ 2.6 DSL Comparison Chart ● 3. Cable Modems ❍ 3.1 IEEE 802.14 ❍ 3.2 Model of Operation ● 4. Future Trends ❍ 4.1 Current Trials ● 5. Summary ● 6. Glossary ● 7. References http://www.cis.ohio-state.edu/~jain/cis788-97/rbb/index.htm (1 of 14) [2/7/2000 10:59:54 AM] Digital Subscriber Lines and Cable Modems 1. Introduction The widespread use of the Internet and especially the World Wide Web have opened up a need for high bandwidth network services that can be brought directly to subscriber's homes. These services would provide the needed bandwidth to surf the web at lightning fast speeds and allow new technologies such as video conferencing and video on demand. Currently, Digital Subscriber Line (DSL) and Cable modem technologies look to be the most cost effective and practical methods of delivering broadband network services to the masses. <-- Back to Table of Contents 2. DSL Technologies Digital Subscriber Line A Digital Subscriber Line makes use of the current copper infrastructure to supply broadband services.
    [Show full text]
  • Broadcast Television (1945, 1952) ………………………
    Transformative Choices: A Review of 70 Years of FCC Decisions Sherille Ismail FCC Staff Working Paper 1 Federal Communications Commission Washington, DC 20554 October, 2010 FCC Staff Working Papers are intended to stimulate discussion and critical comment within the FCC, as well as outside the agency, on issues that may affect communications policy. The analyses and conclusions set forth are those of the authors and do not necessarily reflect the view of the FCC, other Commission staff members, or any Commissioner. Given the preliminary character of some titles, it is advisable to check with the authors before quoting or referencing these working papers in other publications. Recent titles are listed at the end of this paper and all titles are available on the FCC website at http://www.fcc.gov/papers/. Abstract This paper presents a historical review of a series of pivotal FCC decisions that helped shape today’s communications landscape. These decisions generally involve the appearance of a new technology, communications device, or service. In many cases, they involve spectrum allocation or usage. Policymakers no doubt will draw their own conclusions, and may even disagree, about the lessons to be learned from studying the past decisions. From an academic perspective, however, a review of these decisions offers an opportunity to examine a commonly-asserted view that U.S. regulatory policies — particularly in aviation, trucking, and telecommunications — underwent a major change in the 1970s, from protecting incumbents to promoting competition. The paper therefore examines whether that general view is reflected in FCC policies. It finds that there have been several successful efforts by the FCC, before and after the 1970s, to promote new entrants, especially in the markets for commercial radio, cable television, telephone equipment, and direct broadcast satellites.
    [Show full text]