Lecture 1 KNT4073 Introduction Final

8/4/2019 Lecture 1 KNT4073 Introduction Final

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KNT 4073 Telecommunication Networks andServices 1

Telecommunication

Networks and Services

Prepared by

Dr AL-Khalid Othman

Department Electronic and Telecommunication EngineeringFaculty of Engineering

UNIMAS


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Course Aim

The aim of the course is to expose thestudent with the understanding of thetelecommunication network and services both

internationally and locally.


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Learning Objectives

Upon successful completion of this course thestudent is capable of :

discussing the telecommunication industries and itsrelated area

differentiating between different switching technologybeing used and their advantages and disadvantagesrespectively

describing new and advanced telecommunicationnetworking and services

identifying telecommunication network and services inMalaysia


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Teaching - Learning Approach

Lectures

Class tutorials


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Assessment

Test 1 15%

Test 2 15%

Assignments 20%

Final Examination 50%


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Resources

[1] A.L. Garcia & I. Widjaja, Communications Networks- Fundamental Concepts and KeyArchitectures, McGraw-Hill Series, 2000.

[2] S. Kasera & P. Sethi, ATM Networks- Concept and Protocol, Tata McGraw Hill PublishingCompany Limited, 2001

[3] W. Stallings, ISDN and Broadband ISDN with Frame Relay and ATM, 4th Edition PrenticeHall, 1999

[4] W. Goralski, Frame Relay for High Speed Networks, John Wiley & Sons, Inc., 1999.[5] P.S. Neelakanta, A Text Book on ATM Telecommunications, Principle and Implementation,

CRC Press, 2000.[6] Malaysia Government, The National Telecommunication Policy of Malaysia (1994-2020).[7] Malaysia's Regulatory Policy Update APEC Telecommunications and Information Working

Group 27th Meeting | 24-28 March 2003| Kuala Lumpur, Malaysia[8] McCarthy Tetrault, Telecommunication Regulation Handbook Module 5, Competition Policy,

2000.

[9] Byeong Gi Lee and Sunghyun Choi, Broadband Wireless Access and Local Networks:Mobile WiMax and WiFi, Artech House, 2008

[10] Juangzhou Wang, High Speed Wireless Communications: 3G Long-Term Evolution, and 4GMobile System, Cambridge University Press, 2008.

[11] Shih-Lin Wu and Yu-Chee Tseng (eds), Wireless Ad Hoc Networking: Personal-Area, Local-Area, and the Sensory-Area Networks, Auerbach Publications, 2007
http://library.books24x7.com/books.asp?imprintid=30http://library.books24x7.com/books.asp?imprintid=190http://library.books24x7.com/books.asp?imprintid=190http://library.books24x7.com/books.asp?imprintid=190http://library.books24x7.com/books.asp?imprintid=190http://library.books24x7.com/books.asp?imprintid=30http://library.books24x7.com/books.asp?imprintid=30http://library.books24x7.com/books.asp?imprintid=30


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Introduction

Telecommunication Networksand Services


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The Development of

Telecommunications Network

Structures and Services

Standards

The success of a new services

Technology

RegulationMarket


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Factor 1: Technology

Fundamental physicalconsiderations

Technology capabilitiesbased on S- shapedcurve

New invention oftechnology

Capab

ility

Time


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Factor 2: Regulation

Based on Government regulation

Regulation provide a framework thatdetermines what types of services and

networks can be implemented. Addressing the issue of which information

should be available to people over atelecommunications networks.


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Factor 3: Market

Determined by customer

Depend on cost, usefulness, and appeal ofthe service.

Cost of services decrease with the size of thesubscriber base due to economies of scale

Usefulness of service frequently depends onthere being a critical mass of subscribers

Example: email depend on destination Appeal of service depends on comfortability

of service


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Factor 4: Standard

Basically, an agreement to ensureinteroperable among equipment vendors.

Capable talk to one another

Have a choice of buying equipment frommultiple suppliers

Standard are extremely important in

telecommunications where the value of anetwork is to large extent determined by thesize of the community that can be reached.


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Discussion

What are the criteria of designing acommunication network?


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KNT 4073 Telecommunication Networks andServices

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Communication Design Consideration

Range

Power

Cost

Bandwidth Speed

Reliability

Convenience Accuracy


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Range

The further information has to be transmitted, themore difficult it is to get the message throughuncorrupted

Wired link require repeaters for long distances but

work well at low frequencies. Coaxial, optical fibre work with long distance and

high frequencies.

Terrestrial radio links require different frequencies

for different purposes, eg., HF (long distanceionosphere communication across the world); VHF(variety shorter rage uses); UHF (give large BW forTV); medium wave for broadcasting.


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Power

Less power at sending end (Tx), simpler and cheaperfor transmitting installation but Rx can be morecomplex.

Radiated power may need to be kept high to allowthe use of cheap receivers (radio broadcasting)


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Cost

Has to be kept as low as is compatible with achievingthe desired system performance.


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Bandwidth

Large BW increase of cost and complexity of systemdesign.

Example, in telephone channel, the BW is halved atthe start by using SSB (single sided) techniques andthen making what is left for the voices.

The standard voice frequency channel for telephoneis 4KHz.


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Speed

Cheaper system sending information teleprinters,facsimile, SMS.

Sending faster information, more BW required butless time.


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Reliability

How much does it matter if your signal arrivescorrupted?

The aim is to use the cheapest system which will giveacceptable reproducibility of signal.


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Convenience

Encompasses a multitude of factors of which mostrestricting technically is the need for new systems tobe compatible with the existing system.

Use more comprehensive integrated circuits whereaspossible (must be digital); ease for production andcheap for repairing.

Upgrading the system


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Accuracy/Quality

The received signal must be accurate compared tothe original but required more complex andexpensive communication system.


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THE TELEPHONE NETWORK

The Public Switched Telephone Network(PSTN)

Analog Circuits

What is Sound?

The Voiceband

Plain Ordinary Telephone Service (POTS)


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The Public Switched Telephone

Network (PSTN)

Many communication technologies are based onthe Public Switched Telephone Network (PSTN)- voice, data or networking.

It is important to have an understanding of thestructure and operation of the telephonenetwork.


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What is the basic model for the

telephone network?

At the top of the diagram, we have atelephone and a telephone switch.

The telephone is located in a building called a

Customer Premise (CP), and the telephoneswitch is located in a building called a CentralOffice (CO).

One could refer to the telephone as CustomerPremise Equipment (CPE).

Th P bli S it h d T l h


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The Public Switched Telephone

Network (PSTN)


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PSTN

The telephone is connected to the telephone switchwith two copper wires, often called a local loop or asubscriber loop, or simply a loop.

This a dedicated access circuit from the customer

premise into the network. We usually have the same arrangement at the other

end, with the far-end telephone in a differentcustomer premise and the far-end telephone switchusually in a different central office.


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Connection - Why copper?

Copper is a good conductor of electricity - butnot perfect: it has some resistance to the flowof electricity through it.

Because of this, the signals on the loopdiminish in intensity or attenuate withdistance, and if the loop were too long, youwouldn't be able to hear the other person.


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PSTN

The maximum resistance allowed is usually 1300 ohms, whichworks out to about 18,000 feet or 18 kft, which is 3 miles or 5 kmon standard-thickness 26-gauge cable, but could be as long as14 miles or 22 km on thicker 19-gauge cable.

Thus, COs traditionally had a serving area of three miles radius

around them, about 27 square miles or 75 km2

. With suburban sprawl, we can't build COs every five miles, so in

practice, new subdivisions are served from remote switches,which are low-capacity switches in small huts or undergroundcontrolled environment vaults. local loop is essential.


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KNT 4073 Telecommunication Networks and

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PSTN

The remote provides telephone service locally on theloops in the subdivision.

The remote and the loops are connected back to thenearest CO via a loop carrier system that uses fiber

or radio.

Telephone switches are connected with trunks.

While subscriber loops are dedicated access circuits,trunks are shared connections between COs.


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Discuss what do understand about PSTNstructure.


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To establish a connection between one customerpremise and another, the desired network address(telephone number) is signaled to the network (to theCO switch or remote) over the loop, then the switch

seizes an unused trunk circuit going in the correctdirection and the connects the loop to that trunk - forthe duration of the call.

When one end or the other hangs up, the trunk isreleased for someone else to connect between those

two COs.


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PSTN

This method for sharing the trunks is knownas circuit switching.


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Voice and data equipment which connects tothe PSTN over regular telephone lines mustwork within the characteristics of the local

loop, so an understanding of thecharacteristics and limitations of the localloop is essential.


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Analog Circuits

Telephones transmit information over copperwires using voltage

Voltage is a representation of analog from

speakers voice Analog circuit


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Analog Circuits

The technique for representing information on anordinary local loop is called analog.

The term analog comes from the design of thetelephone.

A microphone in the telephone handset is placed in thepath of the sound pressure waves coming out of thespeakers throat.

As the sound pressure waves hit the microphone, theychange its electrical characteristics.


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Analog Circuits

The electrical characteristics of the microphonechange as the sound pressure waves hit it to make avoltage on the telephone wires change.

This voltage is a representation or analogof the

sound pressure waves.

This is all we mean by analog: representation. Thevoltage on the wires is an analog of the soundpressure waves coming out of the speakers throat.


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What is Sound?

Sound is a wave, a longitudinal wave

Sound needs a medium to travel

Sound vibrates the air like a slinky

An echo is a reflection of sound of an object. It's like

playing tennis Sound travels at the speed of sound, surprise! (331

m/s)

The sound phenomena we hear when an ambulance

passes us by is known as the Doppler Effect


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The Voiceband

In electronics, voice band means the typical humanhearing frequency range that is from 20 Hz to 20 kHz.

In telephony, it means the frequency range normallytransmitted by a telephone line, generally about 200

3600 Hz.

Frequency-division multiplexing in telephony normallyuses 4 kHz carrier spacing.

The rate at which the amplitude of a signal drops off

near the upper and lower limits can vary with thedesign of the band-pass filters.


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The question of frequency spacing was addressed atan international meeting in the 1930s.

Germany and Britain favored 2 kHz spacing, whilethe Netherlands and some other countries preferred6 kHz.

The question was compromised at the Americanposition, which was the 4 kHz spacing that remainedstandard and also fixed the standard PCM samplerate at 8 kHz, which in turn defines what "voiceband"means for this purpose.


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Plain Ordinary Telephone Service

(POTS)

Plain old telephone service, or POTS, is a termwhich describes the voice-grade telephone servicethat remains the basic form of residential and smallbusiness service connection to the telephone network

in most parts of the world. The name is a reflection of the telephone service still

available after the advent of more advanced forms oftelephony such as ISDN, mobile phones and VoIP.


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POTS

It has been available almost since theintroduction of the public telephone system inthe late 19th century, in a form mostly

unchanged to the normal user despite theintroduction of Touch-Tone dialing, electronictelephone exchanges and fiber-opticcommunication into the public switched

telephone network (PSTN).


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POTS

The system was originally known as the PostOffice Telephone Service or Post OfficeTelephone System in many countries.

The term was dropped as telephone serviceswere removed from the control of nationalpost offices.


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POTS services :

bi-directional, or full duplex, voice path with limitedfrequency range of 300 to 3400 Hz: in other words, asignal to carry the sound of the human voice bothways at once;

call-progress tones, such as dial tone and ringing

signal; subscriber dialing;

operator services, such as directory assistance, longdistance, and conference calling assistance;

a standards compliant analog telephone interfaceincluding BORSCHT functions
http://en.wikipedia.org/wiki/BORSCHT


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BORSCHT functions

BORSCHT circuitry is typically located on a telecommunications

network line card and is increasingly integrated into a chipset byseveral semiconductor companies for low-cost implementation of astandard POTS telephone interface for non-traditional telephonynetworks such as cable television networks, fiber optic, VoIP andwireless local loop.

Battery feed - device or system that supplies electrical or other types ofenergy to an output load or group of loads.

Overvoltage protection-Used transient voltage suppressor or TVS -ageneral classification of an array of devices that are designed to react tosudden or momentary overvoltage conditions.

Ringing-is the sound made by a telephone to indicate an incoming call.
http://en.wikipedia.org/wiki/BORSCHThttp://en.wikipedia.org/wiki/BORSCHT


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BORSCHT functions

Supervision-a loop start is a supervisory signal givenby a telephone or PBX in response to the completionof the loop circuit, commonly referred to as 'off-hook'.

Codec- device or program capable of performing

encoding and decoding on a digital data stream orsignal.

Hybrid-is a single transformer that has three windings

Testing
http://en.wikipedia.org/wiki/BORSCHThttp://en.wikipedia.org/wiki/BORSCHT


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POTS other features :

Many calling features became available to POTSsubscribers after computerization of telephoneexchanges during the 1970s and 1980s. The servicesinclude:

Voicemail - is a centralized system of managingtelephone messages for a large group of people.

Caller ID - is a telephone service that transmits thecaller's number to the called party's telephoneequipment during the ringing signal or when the call

is being set up but before the call is answered.


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Call waiting - If a calling party places a call to a calledparty which is otherwise engaged, and the calledparty has the call waiting feature enabled,

Speed dialing is the use of a very short series oftelephone numbers to reach public services. Typically

these are two or three digits, and are most commonlyknown as being emergency telephone numbers like1-1-2 and 9-1-1.

Conference call (three-way calling) - is a telephonecall in which the calling party wishes to have more

than one called party listen in to the audio portion ofthe call.


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POTS-Summary

The communications circuits of the PSTN continue to bemodernized by advances in digital communications, however,other than improving sound quality, these changes have beenmainly transparent to the POTS customer.

The function of the POTS local loop presented to the customer

for connection to telephone equipment is practically unchangedand remains compatible even with telephones built in the early20th century.

Due to the wide availability of POTS, new forms ofcommunications devices such as modems and facsimilemachines are designed to use the POTS service to transmit

digital information.


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Discussion

What is the procedure for the telephonenetwork to be connected?


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CONNECTING TELEPHONE

NETWORK


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IP-Telephony

What is Voice-over-IP?

Voice-over-Internet-Protocol or Voice-over-IPor VoIP allows one to send a voice

transmission via a network instead of thestandard telephone infrastructure.

Calls can be routed via the Internet, widearea network (WAN), or local area network

(LAN).

Wh t i IP PBX (I t t


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What is an IP-PBX (Internet

Protocol Private Branch eXchange)?

An IP-PBX is a customer premises business phonesystem that manages telephones throughout theenterprise and acts as a gateway to both voice anddata networks.

An IP-PBX allows you to place calls using a networkinstead of standard telephone infrastructure.

Telephones can be connected to the IP-PBX via thenetwork and calls can be routed via the networkinstead of the standard public switched telephone

network.


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What are the advantages of an IP-

PBX system?

What are the advantages of an IP-


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PBX system?Multiple Branch Offices

With VoIP, expanding your business phone system tomultiple branch office sites is easy.

Integrated IP Gateways allow you to traffic calls betweenoffices over the Internet and save on long distance

charges. Dialing branch offices is as easy as calling an extension

down the hall.

Make certain that your IP-PBX has an administration toolthat simplifies the process of configuring IP gateways

between remote systems.


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Toll Bypass

IP-PBXs enable businesses to reduce the costof long distance calling by routing callsinexpensively over IP networks.

If you have overseas facilities, using an IP-PBXcould reduce your business's costs significantly.

R t Offi


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Remote Office

Even if your business has a single remote office, an IP-PBX can give you the flexibility to pick an affordablesolution.

Purchasing a solution that allows for a small or largenumber of IP trunks might be right for you.

Work From Home

Vertical's sophisticated IP-PBX software extends easilyand seamlessly to your telecommuters, contractors, andconsultants and makes them part of the corporate phone

system.


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Ubiquity and low cost make telephone network anessential component of computer communications.

Telephone network operate on basis of circuitswitching.

Circuit switching involves setting up physical pathfrom one telephone across network to othertelephone.

At telephone offices operators make physical

connections that allows electric current to flow fromone telephone to the other.


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Examples

IP Telephony

PBX 3CX

Etc.


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The switch prepares to accept dialed digitsand provides user with dial tone.

User then enter telephone number that

generates sequence of pulses or sequence oftones. Switch equipment converts these pulses or

tones into a telephone number.

The call setup procedure involves finding apath from source to destination.



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Fig 12 shows a typical arrangement in a metropolitan

area.Fig. 12: Routing in typical metropolitan area

Add i d R ti


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Addressing and Routing

Each subscriber has an address (telephone number)

Addresses are hierarchical Example: Dominos Pizza in downtown Charlottesville

1 804 979 2656

1 804 979

country code; area code; number of local exchange;

2656Subscriber number

The information contained in a telephone address is exploitedwhen establishing a route from caller to callee.


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International standard organisationsfor telecommunications

International Telecommunication


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Union (ITU)

ITU is based in Geneva Comprises of members: countries, industrial companies

and international organizations.

1st July 1994- 3 main sectors

1st sector- Telecommunication Standardization Sector(ITU-T) responsible for setting standards for public voiceand data services (formerly the remit of the ConsultativeCommittee on International Telegraphy and Telephony orCCITT)

2nd sector-Radio Communication Sector (ITU-R) isresponsible for radio frequency spectrum management forboth space and terrestrial use to be performed by the

International Radio Consultative Committee (CCIR). 3rd sector-The development sector (ITU-D) is responsible

for improving telecommunications equipment andsystems in developing countries.



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Union (ITU)

Organize conference on world and/or regional basis andoperate study group

G-Transmission systems and media, digital systems and

networks

H- Audiovisual and multimedia systems

I- Integrated services digital networkP-Telephone transmission quality, telephone installations,

local line networks

Q-Switching and signalling

R-Telegraph transmission

S-Telegraph services terminal equipmentU-Telegraph switching

http://www.itu.int/ITU-T/publications/recs.html


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Other Organizations

International Organization for Standardization-concerns on software issue

Main contribution of ISO -OSI 7 layers

International Electrotechnical Committee (IEC)-

hardware issue

European Telecommunications Standards Institute(ETSI)- developing wide range standards and othertechnical documentation as Europes contribution to

worldwide standardization in telecommunications,broadcasting and information technology.


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Lecture 1 KNT4073 Introduction Final

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