eee402f special tut on telecoms basics.pps

7/28/2019 EEE402F Special Tut on Telecoms Basics.pps

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EEE402F Module B: Convergent Voice and Data NetworkMqhele E. Dlodlo & H. Anthony ChanTelecommunication Basics Tutorial

12 April 2013

EEE402F-b / EEE526Z

Convergent Networks

H Anthony [email protected]

http://www.eng.uct.ac.za/~achan

Mqhele E Dlodlo

[email protected]://www.uct.ac.za/courses/eee_mdlodlo/

Department of Electrical Engineering

University of Cape Town

Special Tutorial on Telecommunications
mailto:[email protected]://www.eng.uct.ac.za/~achanmailto:[email protected]:[email protected]://www.eng.uct.ac.za/~achanmailto:[email protected]


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12 April 2013

Aims

To review the Basic Principles of Telecommunications

To outline necessary background knowledge for higher levelsystems analysis, design, selection and management

To identify critical systems characteristics

To identify telecommunication systems as: Radio Systems

Data Systems, and

Television Systems

To outline a sample of Business Services offered byTelecommunication Systems

To cite some strategic issues facing telecommunicationsystems


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Objectives

To demonstrate an understanding of the

place of data communications in

telecommunication systems

To show an appreciation of the ubiquity of

telecommunications in todays society

To show an ability to identify and explain

system characteristics


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Telecommunication

The extension of communication over a distance,under the practical constraints of attenuation, noiseand interference such that something may be lostin the process; hence the term 'telecommunication'

covers all forms of distance and/or conversion ofthe original communications, like radio,

telegraphy,

television, telephony,

data communication and

computer networking.


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Telecommunication Systems

A telecommunication system receives and converts someoriginal information energy (voice, music, video, data) intoan electronic information signal, transmits the signal andconverts the signal at the destination back to its desiredform. No live transfer!

Examples include: Telephone networks

Data communication networks

Computer networks

Broadcast networks radio and television

Main Types: Line systems

Radio systems

Satellite-based systems


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Elementary Concepts Wire-line

A line system passes the electronic

information signal down a wire, cable or fibre

link (or a combination of these)

The propagation speed can be as low as

60% the speed of light in some media.

A source encoder converts analogue

information into a Pulse Code Modulated

(PCM) signal before transmission


7/19EEE402F Module B: Convergent Voice and Data NetworkMqhele E. Dlodlo & H. Anthony ChanTelecommunication Basics Tutorial

12 April 2013

Elementary Concepts - Wireless

In a radio system, the source converts the energyinto an electromagnetic radio signal to transmitover a radio link

The propagation proceeds at the speed of light

In either case, there will be signal degradation dueto electronic noise and other mechanisms

The objective of systems design is to minimisesuch distortions

Interactive telecommunication systems require two-way or duplex channels, but broadcast systemsneed only simplex or one-way channels



12 April 2013

Line System Characteristics

Attenuation and Noise

Modulation: AM, FM, PM, PCM

Twisted pair copper wires

Coaxial cable or tube

Optical fibre

Transmission line characteristics



12 April 2013

Wireless System Characteristics

Electromagnetic radio waves: Surface wave

Sky wave (via ionosphere)

Space wave (line-of-sight and reflected)

Satellite transponder radiation

Tropospheric scatter Electromagnetic light waves (pulsed infra red laser light)

Propagation

Antenna design

Satellite link design

Land-mobile access network design

Maritime communication systems design

Error-control coding

Multiple access control schemes

Detection schemes, e.g. joint detection


10/19EEE402F Module B: Convergent Voice and Data NetworkMqhele E. Dlodlo & H. Anthony Chan

Telecommunication Basics Tutorial

12 April 2013

Data Networks and Systems

Open Systems Interconnection Model

Internetworking Model

Data services and packet switching

Frame mode bearer services

Local area networks (LANs)

Wide area networks (WANs)




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Signalling, Transmission and Switching

Signalling: passing of information from one point to anotherfor setting up or supervision of a telephone call or a dataexchange session

Transmission: dispatch and propagation of a signal,

message, or other form of information by any means, suchas by telegraph, telephone, radio, television, or facsimile viaany medium, such as wire, coaxial cable, microwave, opticalfibre, or radio frequency.

Switching: the process of making connections and relayinginformation between a calling party and a called partyusually through a combination of space and time divisionmultiplex apparatus in the exchange fabric




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ITU-T Signalling System No. 7

Is extended to data and multimedia control

Separates signalling and user traffic

Provides better support for services like:

network management

Network maintenance

Centralised call accounting




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Transmission

The central problem of transmission is the conveyance of signals aswaves over distances significant with respect to the wavelengthsinvolved

Large volumes of data are regularly transmitted sequentially making itnecessary to encode the information into a signal

A travelling sinusoidal wave progressively experiences increased phasedelay and attenuation with distance in the direction of propagation

The main characteristics of transmission media are the propagationconstant, characteristic impedance and reflection coefficient

Transmission media include twisted copper wire pairs, coaxial cables,strip lines, waveguides, optical fibre and free space

Transmission system design and analysis relies greatly onelectromagnetic theory as well as differential and integral calculus




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Switching Principles

Goal: to enable any terminal (telephone, data terminal,computer) as requested by the calling party

Switching centre telephone exchange

Full mesh backbone or core networks Digital switching time division stages shift PCM words in

time between incoming and outgoing channels, multiplexingthem onto different time slots

Space division provides direct physical paths right through

the exchange connecting the local loops of one subscriberto that of another.




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Evolving Core Switching Technologies

Frame Relay (FR)

Asynchronous Transfer Mode (ATM)

Internet Protocol (IP)

IP Virtual Private Network (IP VPN)




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Business Services

Private Automatic Branch Exchange, key-phones, Centrex

Virtual Private Networks (VPN)

Private networks and leased lines

Conference calling ISDN supplementary services

Mobile telecommunication systems paging, SMS, voice,remote login, email, Internet access

Free-phones0800 series

Facsimile

Interactive services teletex, teletext, email, EFT-POS,credit cards, smart cards, voice mail

Voice over IP


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Personal Consumer Services

Television Services High Definition Television (HDTV)

Direct Satellite Television (DSTV/DBS)

Cable Television

Asynchronous Digital Subscriber Line (ADSL) and variants

Wireless Local Loop Dial-up Email or Internet Access

Telephone Banking

Internet Banking

Automatic Teller Machines

Phone Cards Emergency Services

Online Directory Services

Online Shopping


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Strategic Issues

Telecommunications network numbering

Telecommunications standards

Telecommunications network management

Centralised maintenanceReliability

Voice tariffs

Forecasting future demand

Telecommunications security

Telecommuting

Convergence of technologies


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EEE402F-b / EEE526Z

Convergent Networks

The ability to communicate with high speed network

at affordable price is important to the people,

business, and industry in every country to complete

in global market.www.uct.ac.za/depts/commnetwork/

2005

Ref: G. Langley & J. P. Ronyne; Telecommunications

Primer, 4/e; Pitman Publishing, 1993

eee402f special tut on telecoms basics.pps

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