Practical Fundamentals of Telecommunications and Wireless Communications

Transcription

1 Practical Fundamentals of Telecommunications and Wireless Communications

2 THIS BOOK WAS DEVELOPED BY IDC TECHNOLOGIES WHO ARE WE? IDC Technologies is internationally acknowledged as the premier provider of practical, technical training for engineers and technicians. We specialize in the fields of electrical systems, industrial data communications, telecommunications, automation and control, mechanical engineering, chemical and civil engineering, and are continually adding to our portfolio of over 60 different workshops. Our instructors are highly respected in their fields of expertise and in the last ten years have trained over 200,000 engineers, scientists and technicians. With offices conveniently located worldwide, IDC Technologies has an enthusiastic team of professional engineers, technicians and support staff who are committed to providing the highest level of training and consultancy. TECHNICAL WORKSHOPS TRAINING THAT WORKS We deliver engineering and technology training that will maximize your business goals. In today s competitive environment, you require training that will help you and your organization to achieve its goals and produce a large return on investment. With our training that works objective you and your organization will: Get job-related skills that you need to achieve your business goals Improve the operation and design of your equipment and plant Improve your troubleshooting abilities Sharpen your competitive edge Boost morale and retain valuable staff Save time and money EXPERT INSTRUCTORS We search the world for good quality instructors who have three outstanding attributes: 1. Expert knowledge and experience of the course topic 2. Superb training abilities to ensure the know-how is transferred effectively and quickly to you in a practical, hands-on way 3. Listening skills they listen carefully to the needs of the participants and want to ensure that you benefit from the experience. Each and every instructor is evaluated by the delegates and we assess the presentation after every class to ensure that the instructor stays on track in presenting outstanding courses. HANDS-ON APPROACH TO TRAINING All IDC Technologies workshops include practical, hands-on sessions where the delegates are given the opportunity to apply in practice the theory they have learnt. REFERENCE MATERIALS A fully illustrated workshop book with hundreds of pages of tables, charts, figures and handy hints, plus considerable reference material is provided FREE of charge to each delegate. ACCREDITATION AND CONTINUING EDUCATION Satisfactory completion of all IDC workshops satisfies the requirements of the International Association for Continuing Education and Training for the award of 1.4 Continuing Education Units. IDC workshops also satisfy criteria for Continuing Professional Development according to the requirements of the Institution of Electrical Engineers and Institution of Measurement and Control in the UK, Institution of Engineers in Australia, Institution of Engineers New Zealand, and others.

3 CERTIFICATE OF ATTENDANCE Each delegate receives a Certificate of Attendance documenting their experience. 100% MONEY BACK GUARANTEE IDC Technologies engineers have put considerable time and experience into ensuring that you gain maximum value from each workshop. If by lunchtime on the first day you decide that the workshop is not appropriate for your requirements, please let us know so that we can arrange a 100% refund of your fee. ONSITE WORKSHOPS All IDC Technologies Training Workshops are available on an on-site basis, presented at the venue of your choice, saving delegates travel time and expenses, thus providing your company with even greater savings. OFFICE LOCATIONS AUSTRALIA CANADA INDIA IRELAND MALAYSIA NEW ZEALAND POLAND SINGAPORE SOUTH AFRICA UNITED KINGDOM UNITED STATES idc@idc-online.com Visit our website for FREE Pocket Guides IDC Technologies produce a set of 6 Pocket Guides used by thousands of engineers and technicians worldwide. Vol. 1 ELECTRONICS Vol. 4 INSTRUMENTATION Vol. 2 ELECTRICAL Vol. 5 FORMULAE & CONVERSIONS Vol. 3 COMMUNICATIONS Vol. 6 INDUSTRIAL AUTOMATION To download a FREE copy of these internationally best selling pocket guides go to:

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6 IDC Technologies Pty Ltd PO Box 1093, West Perth, Western Australia 6872 Offices in Australia, New Zealand, Singapore, United Kingdom, Ireland, Malaysia, Poland, United States of America, Canada, South Africa and India Copyright IDC Technologies 2012 All rights reserved. First published 2008 All rights to this publication, associated software and workshop are 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 written permission of the publisher. All enquiries should be made to the publisher at the address above. Disclaimer Whilst all reasonable care has been taken to ensure that the descriptions, opinions, programs, listings, software and diagrams are accurate and workable, IDC Technologies do not accept any legal responsibility or liability to any person, organization or other entity for any direct loss, consequential loss or damage, however caused, that may be suffered as a result of the use of this publication or the associated workshop and software. In case of any uncertainty, we recommend that you contact IDC Technologies for clarification or assistance. Trademarks All logos and trademarks belong to, and are copyrighted to, their companies respectively. Acknowledgements IDC Technologies expresses its sincere thanks to all those engineers and technicians on our training workshops who freely made available their expertise in preparing this manual.

7 Contents 1 Introduction to Telecommunications Telecommunications Principles of Telecommunication Services Telecommunication Standards 2 2 Telecommunications Basics Concepts Simplex, Half-Duplex and Full-Duplex Transmission Modulation Techniques Baseband Vs Broadband Narrowband Vs Wideband Analog Vs Digital Transmission Dial-Up Vs Leased Access Multiplexing Techniques Connection-Oriented Vs Connectionless Communication Local Vs Wide Area Networks The PSTN Vs the Internet The Open Systems Interconnection Model 23 3 Transmission Media Basic Cable Parameters Conducted Transmission Media Coaxial Cable Fiber Optic Cable 48 4 Terrestrial Microwave and Satellites Terrestrial Microwave Satellites 62 5 The Public Switched Telephone Network Introduction Local Network Subscriber Plant Telephone Switching Infrastructure Local Switches Subscriber Line Circuit Truck Switching CCI Signaling System No. 7 92

8 6 Private Switched Telephone Network Private Branch Exchange (PBX) Centrex Key Systems DECT Computer Telephony Integration (CTI) Other Services Public Network Transport Technologies Switched Analog Services Leased Analog Data Services Digital Transmission Hierarchies Switched Digital Services Switched Integrated Services Data Network (ISDN-BRI) Frame Relay Switched Multi-Megabit Data Services (SMDS) ATM Digital Dedicated Circuit (Leased) Alternatives Integrated Services Data Network Primary Rate Interface (ISDN-PRI) Broadband ISDN (B-ISDN) Synchronous Digital Hierarchy (SDH/SONET) Customer Access Technologies (Broadband) DSL Technologies Full Rate ADSL ADSL2/ADSL HDSL SDSL/SHDSL Very-High Speed Digital Subscriber Line (VDSL) Etherloop Hybrid Fiber Coax (HFC) Fiber to the Curb (FTTC) Fiber to the Home (FTTH) Multi-Channel Multipoint Distribution System (MMDS) Local Multipoint Distribution System (LMDS) Wimax Power System Carrier VSAT Networking Basics Introduction LAN Topologies Media Access Control 189

9 9.4 LAN Standards LAN Extension and Interconnecting Devices Converged Networks Applications Protocols Summary H Implementation Considerations: Qos Cellular Services Cellular Transmission Concepts First Generation (1G) Cellular Systems Second Generation (2G) Cellular Systems Third Generation (3G) Cellular Systems Cordless Phone Systems Mobile Data Transmission WAP Private Mobile Radio (PMR) Systems Wireless LANS Introduction Architecture Specifications Medium Access Control Frame Structure 287 Appendix A Practical Session Data 295 Appendix B - Glossary 309 Appendix C Questions & Answers 327

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11 1 Introduction to Telecommunications Learning objectives After studying this chapter you will: Understand the basic principles of Telecommunications Be familiar with some of the better-known Telecommunication standards bodies 1.1 Telecommunications The word telecommunication is derived from the Greek tele, meaning at a distance. Communications refers to the science and practice of transmitting information. A more relevant definition is given in the Dictionary of Communications Technology, which defines it as a term encompassing the transmission or reception of signals, images, sounds, or information by wire, radio, optic, or infrared media. Telecommunications play a vital role in international commerce, and in industrialized nations it is an accepted necessity. The telecommunications networks in all countries are interlinked to form a global telecommunications network for carrying information of all kinds. The Public Switched Telephone Network (PSTN) was originally developed solely for carrying voice communications, but today carries an ever-increasing amount of data communications traffic. The Internet uses the PSTN circuits to carry some of its data and the phenomenal growth of the Internet has stimulated the growth of data circuit usage in the PSTN. In some countries, Internet traffic accounts for more than half the total PSTN traffic. Cellular radio services are having an enormous impact on the growth of telecommunications networks. In industrialized countries they are used increasingly for mobile business communications. However, in developing countries, they enable many

12 2 Practical Fundamentals of Telecommunications and Wireless Communications customers in the main population centers to obtain affordable telecommunications services. With cellular services the telecommunications provider does not have to invest in the very high costs of a fixed subscriber distribution plant for individual customers and can serve thousands of customers from one transmitter site. Service can be supplied almost immediately. 1.2 Principles of telecommunication services Telecommunications services follow the following principles: The telecommunications networks are used to provide services to the users A service requires the execution of a series of programs by the originating and destination entities The services are decomposed into different layers by the initiating entity, where each layer undertakes a specified portion of the overall service. This makes the services more manageable and allows interoperability between vendors. Most modern systems adhere to the 7-layer OSI reference model The telecommunications services include information transfer, signaling, and billing Information is transferred over the network in the form of bits. These bits have different forms depending on the type of the transmission media; electrical signals on copper cables, pulses of light in fiber optic cables and electromagnetic waves traveling through space Signals can be corrupted during transmission, due to interference Protocols incorporate error correction and detection mechanisms to overcome errors 1.3 Telecommunication standards Telecommunications standards are essential in allowing the global PSTN to function. It is clear that when a telephone call or data message originates in one country and terminates in another, both sender and recipient need to understand each other's messages. This is achieved by using standardized message formats. This enables a message to be successfully passed through a number of countries, as necessary, along the way. Standardization is provided by two international organizations; the International Telecommunication Union (ITU), and the International Organization for Standardization (ISO). These are supplemented by many national standardization agencies. The ITU produce recommendations that serve as world-wide standards, although they are not legally binding. Prior to January 1993 the ITU s telecommunication recommendations were promulgated by the CCITT, the International Consultative Committee for Telephone and Telegraph, which has now been reorganized into the Telecommunication Standardization sector of the ITU. Their recommendations are denoted ITU-T. In similar fashion the International Consultative Committee for Radio (CCIR) handled the standardization of radio communications. This has now become the ITU Radio communication Sector and produces ITU-R recommendations.

13 Introduction to Telecommunications 3 The ISO has issued many important data communications standards. One of the most important is the Open Systems Interconnection Reference Model, which we will discuss later. Many national standards organizations are affiliated to ISO, including the American National Standards Institute (ANSI). Some of the other important telecommunication standards organizations are: Electronics Industries Association (EIA) Telecommunication Industry Association (TIA) European Telecommunication Standardization Institute (ETSI) Institute of Electrical and Electronic Engineers (IEEE) International Electro-technical Commission (IEC) Telecommunications standards are also developed by groups of manufacturers that formulate standards. These often become ad hoc industry standards and may subsequently be incorporated in the recommendations of the International standards organizations. Some examples of these groups are the Frame Relay Forum, the ADSL Forum and the ATM Forum.

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