BSNL is India's largest telecommunication company, providing basic telephony and 3G services. The document discusses BSNL's history and network infrastructure, including how calls are routed through exchanges and technologies like PCM, GSM, broadband, WiMAX, and optical fibers. It describes the components and functions of telecom exchanges, switches, and transmission systems that enable telecommunication services.

1. Presented By:-
Anuj Varshney
(1103031029)

2.  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 Technologies
o WiMAX
o 3G
o Optical Fibers
 Conclusion
 Conclusion
 Reference

3.  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.

4. Company Name: Bharat Sanchar Nigam Ltd.
Type: State-owned enterprise
Founded: 15 September 2000
Headquarters: New Delhi, India
Industry: Telecommunications
Employees: 2,44,891
Owner(s): Government of India
Website: www.bsnl.co.in

5. 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

9. Provides the switching facility
Connection to the outside of the exchange
Contains telephone switching hardware such as
cabinets, racks, slots and cards

10. (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.

11. 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

12. 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
Regenerati
ve repeater
Decoder
Reconstruc
tion filter
Destinatio
n

13. 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.
13

14. MS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BTS
BSC
BSC
PSTN
VLR
TRAU
HLR
EIR
SMSC
BC
AUC
VMSC
MSC
A

15.  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.
15

16.  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.
16

17. 17
 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

18. 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.
18

19. ALTTC/DX/IBB_OV/AKN
19
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

20. 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 conferencing
To provide both prepaid and postpaid broadband
services
Broadband Services

21. • 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

22. 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

23. • 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.

25. 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.

26.  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.

27. Optical fibers come in two types:
 Single-mode fibers
 Multi-mode fibers

28. 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.

32.  Carry plain old telephone service (POTS)
 For transmission of data
 Transmitting broadband signals
 In the biomedical industry
 Non-Communication Applications (sensors
etc…)

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

34.  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.

35. 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 India
Training aimed at providing the students with basic
knowledge about telecommunications and the
working of telecom exchanges

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

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