Pawan..bsnl

PRESENTED BY-

SUMMER TRAINING ON

PAWAN BHARTIE.C.E. 4TH YEAR

INTRODUCTION DIVISION OF EXCHANGE MAIN DISTRIBUTION FRAME POWER SECTION PCM ROOM SWITCH ROOM BROADBAND SERVICES INTRODUCTION TO GPRS GPRS ARCHITECTURE OPTICAL FIBER GSM

CONTENTS

Bharat Sanchar Nigam Limited(BSNL) is a Govt. of India Enterprises.

BSNL provides telecom services all over the India.Technological developments in the field of

telecommunication in India have been taking place at much faster as per the global trend. Particularly during last three years.

There has been a major transformation in the switching technology.

INTRODUCTION

DEVELOPMENT OF ELECTRONIC EXCHANGE

At the beginning of electronic exchange vacuum tubes and gas tubes were used as switching devices.

By the development of semiconductor devices , diodes,transistors,FET,CMOS are used as a switching devices.

1ST GENERATION- In control circuits of switch room integrated circuits are used in ICs which are different type of logic gates,counter,flip-flop,timers, multiplexers etc.2ND GENERATION- In this signals are stored in PROMs and signals for call processing and for supervision are obtained in the output of the memory. In such exchange gates multiplexers, flipflop,counters timers and RAM are used.3RD GENERATION- In the third generation stored program control switching(SPC switching) is used.

DIFFERENT GENERATION OF ELECTRONIC

EXCHANGE

-

To obtain flexibility in interconnecting, external line plants and the exchange equipment and between different circuits in the exchange itself, certain arrangements is made by the use of iron frames.

The primary function of MDF is to remove fault. It is also known as Fault Remove Section It is divided into two parts.

1) Exchange side: exchange side is connect with the switch room.

2) Line side: line side is connected with the subscribers.

M.D.F. (main distribution frame)

A means for permanently terminating the external cables.For mounting the protective devices connected to the

incoming circuits.Providing the connection between the exchange side and

the line side by the jumpers.An interception point for use in connection with fault

locating tests.

Facilities provided by M.D.F.

This is one of the important section of the exchange which control the whole exchange runs.

The power can be provided using one of the following methods.

Direct mains supply which is converted into dc with the help of rectifiers.

Power generator Battery

POWER SECTION

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

At present, Switching system is based on the principle of stored program control(SPC).

Program related to call processing divided in different stages of system & are stored in its RAM/ROM.

Processer used in control unit’s handle or process the call is to establish a connection between incoming and outgoing edges of a switch.

Switch Room

The term broadband refers to a telecommunication signal of greater bandwidth.

It is used to provide high speed internet connectivity(up to 8 Mbps)

To provide VPN services to the broadband customers

To provide video and audio conferencingTo provide both prepaid and postpaid broadband

services

Broadband Services

GPRS is a data service for GSM, European standard digital cellular service.

It is a packet-switched mobile data service.It is a wireless packed based network.GPRS further enhancing GSM network to carry data, is

also an important component in the GSM evolution entitled GSM+high-speed mobile data usage is enabled with GPRS

GPRS

GPRS is ideal for sending and receiving the data via the mobile station.

This enables the user to send information via E-mail and also have access to mobile internet services.

It is used for virtual market application It is used for E- commerce

Services GPRS provides

Optical Fiber

The idea of fiber optics is use to light, instead of current or voltage, as the energy which carries the signal, with the light as a carrier that is turned on and off, with binary amplitude modulation.

It is composed

of fine threads of glass in layer called core and cladding.The core has higher refractive index then then cladding. It works on the principle of total internal reflection with in a

fiber core.

TOTEL INTERNAL REFLECTION

Optical Fiber Cable:

Global system for mobile communication (GSM) is a globally accepted standard for digital cellular communication. GSM is the name of a standardization group established in 1982 to create a common European mobile telephone standard

GSM is a cellular network which means that mobile phones connect to it by searching for cells in the immediate vicinity. GSM operates in the 900 MHz frequency band.

GSM

GSM System Architecture

BSC

BSC

MSC

MS

MS

MS BTS

BTS

BTS

GMSC

PSTNISDNPDN

EIRAUC

HLR

VLR

System Architecture Mobile Station (MS)

Mobile Equipment

Portable , vehicle mounted, hand held device. Uniquely identified by an IMEI (International Mobile

Equipment Identity) Voice and data transmission Monitoring power and signal quality of surrounding

cells for optimum handover Power level : 0.8W – 20 W 160 character long SMS.

System Architecture Base Station Subsystem (BSS)

Base Station Subsystem is composed of two parts that communicate across the standardized interface allowing operation between components made by different suppliers

1. Base Transceiver Station (BTS)

2. Base Station Controller (BSC)

System Architecture Base Station Subsystem (BSS)

Base Transceiver Station (BTS):

Encodes , encrypts ,multiplexes , modulates and feeds the RF signals to the antenna.

Frequency hopping Communicates with Mobile station and BSC Consists of Transceivers (TRX) units

System Architecture Base Station Subsystem (BSS)

Base Station Controller (BSC)

Manages Radio resources for BTS Assigns Frequency and time slots for all MS’s in its area Handles call set up Handover for each MS Radio Power control It communicates with MSC and BTS

System Architecture Network Switching Subsystem(NSS)

Mobile Switching Center (MSC)

Heart of the network Manages communication between GSM and other

networks Call setup function and basic switching Call routing Billing information and collection Mobility management

- Registration- Location Updating- Inter BSS and inter MSC call handoff

MSC does gateway function while its customer roams to other network by using HLR/VLR.

System Architecture Network Switching Subsystem

Home Location Registers (HLR)

- permanent database about mobile subscribers in a large service area(generally one per GSM network operator)

- database contains prepaid/postpaid , roaming restrictions , supplementary services.

Visitor Location Registers (VLR)

- Temporary database which updates whenever new MS enters its area, by HLR database

- Controls those mobiles roaming in its area - Reduces number of queries to HLR - Database contains IMSI Location Area , authentication key

System Architecture Network Switching Subsystem

Authentication Center (AUC) - Protects against intruders in air interface- Maintains authentication keys and algorithms and

provides security - Generally associated with HLR

Equipment Identity Register (EIR)- Database that is used to track handsets using the IMEI

(International Mobile Equipment Identity)- Made up of three sub-classes: The White List, The Black List and

the Gray List- Only one EIR per PLMN

CONCLUSION

In the service sector, telecom industry is the most active and attractive.

Though the telecom industry is growing rapidly India's telecom density is less than the world's average telecom density as most of India's market is yet to be covered.

At present, there are nearly 400 million telecom connections in the country and every month 10 million new connections are being added.

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