Bsnl training 4th year

Presented By:-Anuj Varshney(1103031029)

Contents History of BSNL Company Profile Telecom Network

◦ Call Setup◦ HOW SUBSCRIBER REACHES TO EXCHANGE◦ Function of exchange◦ How a Telecom Exchange Works? ◦ Switch Room◦ MDF

Pulse Code Modulation Mobile Department- GSM technology Broadband Technologieso WiMAXo 3Go Optical Fibers Conclusion

Conclusion Reference

INTRODUCTION

Profile at a glance India’s oldest and largest communication service provider 4th largest telecommunication company in asia and 7th

largest in the world. Provides GSM and basic telephony service and first

company in India providing 3G. More than 3 laces of employees, officers and engineers are

working at present.

Company Name: Bharat Sanchar Nigam Ltd.Type: State-owned enterpriseFounded: 15 September 2000Headquarters: New Delhi, IndiaIndustry: Telecommunications Employees: 2,44,891Owner(s): Government of IndiaWebsite: www.bsnl.co.in

When a subscriber calls to another subscriber first its request goes to the nearest switching centre that is PSTN

If subscriber is not in the same BSC (Base Switching Centre) then call transfer to MSC

If Caller calls to a mobile subscriber then call transfer is done by MTSO

Provides the switching facility Connection to the outside of the exchangeContains telephone switching hardware such as

cabinets, racks, slots and cards

(Main Distribution Frame)

• M.D.F. is a media between switching network and subscriber’s line

• It is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires.

• It consists of local connection and broadband connection frames

• It provides testing of calls.• All lines terminate individually.

Pulse Code Modulation

Pulse Code Modulation (PCM) system is used to transmit the spoken word in digital form. PCM systems use TDM technique to provide a number of circuits on the same transmission medium.Basic Requirements for PCM System Filtering Sampling Quantisation Encoding Line Coding

PCM Room consist of PCM transmitter and PCM receiver.

Block diagram of transmitter

Block diagram of receiver

PCM Room

Low pass filter sampler Quantizer Encoder

Regenerative

repeaterDecoder

Reconstruction filter

Destination

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MOBILE DEPARTMENT GSM TECHNOLOGY

GSM is the Global System for Mobile Communication. GSM is an international digital cellular telecommunication standard. It is a fully digital system.

A GSM system has up to a maximum of 200 full-duplex channels per cell. Each channel consists of a downlink frequency and an uplink frequency.

GSM handles channel access using a combination of slotted ALOHA, FDM and TDM.

GSM Network Architecture

MS

BTS

BTS

BTS

BTS BTS

BTS

BTS

BTS

BSC

BSC

PSTN

VLR

TRAU HLREIR

SMSC

BC

AUC

VMSC

MSC

Abis

A

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Components of GSM Network

MOBILE SWITCHING CENTRE (MSC)It manages communication between caller, users and other network users. MSC does gateway function while communication is to be established between its customers to other network customers.

HOME LOCATION REGISTER (HLR) A home location register is a database

that contains subscriber’s location information.

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VISITOR LOCATION REGISTER (VLR)A VLR is a database which contains temporary information concerning the mobile subscriber currently located in a given MSC area, but whose HLR is elsewhere.

BASE STATION CONTROLLER (BSC)The BSC is the radio resource management for all under its control. It controls frequency hopping. It performs traffic concentration to reduce the number of lines from BSC to MSC and BTS.

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Function Of BTS Encodes, encrypts, multiplexes,

modulates and feeds the RF signals to the antenna

Transcoding and rate adaption Functionality

Time and frequency synchronisation signals transmission.

11 power classes from .01 watts to 320 watts

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MOBILE DEPARTMENT GSM TECHNOLOGY

GSM is the Global System for Mobile Communication. GSM is an international digital cellular telecommunication standard. It is a fully digital system.

A GSM system has up to a maximum of 200 full-duplex channels per cell. Each channel consists of a downlink frequency and an uplink frequency.

GSM handles channel access using a combination of slotted ALOHA, FDM and TDM.

Broadband Technologies

ALTTC/DX/IBB_OV/AKN

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Broadband Technologies

Wireless

3G Mobile

Wireline

Wi-Fi (Wireless Fidelity)

Satellite

DSL (Digital Sub’s Line)

Cable Modem

Optical Fibre Technologies

PLC (Power Line Communication)

WiMAX

The term broadband refers to a telecommunication signal of greater bandwidth.IT IS USEDTo provide high speed internet connectivity(up to 8 Mbps)To provide VPN services to the broadband customersTo provide video and audio conferencingTo provide both prepaid and postpaid broadband services

Broadband Services

WiMAX Highlights• WiMAX

– Worldwide Interoperability for Microwave Access

– Is a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16

– provides wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access

WiMAX Applications• According to WiMAX Forum it supports 5 classes of

applications:

1. Multi-player Interactive Gaming.

2. Video Conference

3. Streaming Media

4. Web Browsing and Instant Messaging

5. Media Content Downloads

3G COMMUNICATION

• 3G is the next generation of wireless network technology; it is also known as UMTS (Universal Mobile Telecommunication System).

• It provides high speed bandwidth (high data transfer rates) to handheld devices.

• Specifically, 3G wireless networks support the following maximum data transfer rates:-

2 M bits /second to stationary devices. 384 Kbits/ second for slowly moving devices, such as a handset

carried by a walking user. 128 Kbits/second for fast moving devices, such as handset in

moving vehicles.

OPTICAL FIBER:-

Optical fibers are long, thin strands of very pure glass usually 120 µm in diameter. They are arranged in bundles called optical cables and used to transmit light signals over long distances. Parts of optical fiber:-• Core – thin glass center of the fiber where light travels.• Cladding – outer optical material surrounding the core.• Buffer Coating – plastic coating that protects the fiber.

Total Internal Reflection

The angle of the light is always greater than the critical angle.

Cladding does not absorb any light from the core.

The extent that the signal degrades depends upon the purity of the glass and the wavelength of the transmitted light.

Types of Optical Fibers

Optical fibers come in two types:

Single-mode fibers

Multi-mode fibers

Single-mode fibers:-Single-mode fibers are used to transmit one signal per fiber (used in telephone and cable TV). They have small core (9 microns in diameter) and transmit infra-red light from laser.Multi-mode fibers:-Multi-mode fibers are used to transmit many signals per fiber (used in computer networks). They have larger cores (62.5 microns in diameter) and transmit infra-red light from LED.

Applications Carry plain old telephone service

(POTS) For transmission of data Transmitting broadband signals In the biomedical industry Non-Communication Applications

(sensors etc…)

Advantages

Less Expensive Thinner High Carrying Capacity Less Signal Degradation Light Signals Low Power Digital signals Light Weight

Disadvantages Fiber optics are that the cables are

expensive to install. The termination of a fiber optic cable is

complex and requires special tools. They are more fragile than coaxial

cable.

Bharat Sanchar Nigam Ltd. Formed in October 2000 is the world’s 7th

largest Telecommunications company Presently it is one of the largest and leading public

sector unit in IndiaTraining aimed at providing the students with

basic knowledge about telecommunications and the working of telecom exchanges

BSNL In-plant training material www.bsnl.co.in www.wikepedia.org Telecommunication system engineering by Roger

L Freeman

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