Bharat Sanchar Nigam Limited (BSNL) is the 4th largest telecommunications company in Asia and 7th largest globally, providing GSM and basic telephony services in India. It has over 3 lakh employees. BSNL offers wireless local loop (WLL) services, including fixed and portable WLL, using radio frequencies to connect to the public switched telephone network. Key features include dynamic locking of STD/ISD calls and call waiting/forwarding. The summary provides an overview of BSNL and its WLL services.

1. AT BHARAT SANCHAR NIGAM LIMITED

2.  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.

3. -> WLL (wireless in locked loop)
-> GSM (global system for mobile communication)
-> CDMA (code division multiple access)
-> MTNL ( mahanagar telephone nigam limited)

4. What is WLL?
-Communication system that connects us to PSTN.
- Use Radio Frequency Signals.
- Useful for Subscribers located in pockets.

5. Provides 2 types of services –
(1)Fixed WLL
(2) WLL with portability
Features of WLL –
i) Dynamic STD/ISD locking.
ii) Call Waiting / Call transfer.
iii) Call Forwarding.
iv) STD / ISD call details.

6. - Provided using a telephone instrument.
- FWT will be wall mounted.
-Short cable connected from outdoor
aerial to wall set.
- Wall set powered by an a.c. supply.

7. -Provides portability feature to WLL subscriber.
- This can be done by a portable hand Set which
can be carried in the pocket.

8. History
- Torleiv Maseng is regarded as the father of the GSM
Technology.
- 1989, GSM responsibility was transferred to the
European Telecommunications Standards Institute (ETSI)
- first GSM network was launched in 1991 by Radiolinja in
Finland with joint technical infrastructure maintenance
from Ericsson.

9. • 2G GSM networks operate in the 900 MHz or
1800 MHz bands
• GSM-900 uses 890–915 MHz to send information
from the mobile station to the base station (uplink)
• 935–960 MHz for the other direction (downlink),
• providing 125 RF channels (channel numbers 0
to 124) spaced at 200 kHz. Duplex spacing of 45
MHz is used

11. • MS refers to the physical
phone itself.
• uniquely identified by the
International Mobile
Equipment Identity (IMEI)
number.
• Sim is small smart card that
is inserted into the phone and
carries information specific to
the subscriber

12. • carry out radio communications
between the network and the MS
• handles speech encoding,
encryption, multiplexing (TDMA),
and modulation/demodulation
•between 1 and 16 Transceivers
(TRX)

13. • allocation of radio channels
•frequency administration
•power and signal measurements
from the MS,
•handovers from one BTS to
another

14. • call routing, call setup, and basic
switching functions
• iner-BSC handoffs as well as
coordinates with other MSC's for
inter-MSC handoffs.

15. • gateway between two
networks
• switch to the Public Switched
Telephone Network (PSTN).

16. • HLR maintains subscriber-
specific information such as the
MSISDN, IMSI, current
location
of the MS, roaming
restrictions,
• VLR is a database that
contains
a subset of the information
located on the HLR

17. • EIR is a database that keeps
tracks of handsets on the network
using the IMEI
• handles the authentication and
encryption tasks for the network

18. ◦ All PSTN applications
 Integrated access node
 CSNMM - ADSL + Voice
 Backward compatible with
 CSNMA
 CSE
 Support for V5.2 for access nodes
 Trunk Automatic Exchange (TAX)
 International Gateway
 Signaling transfer point (STP)
◦ IN
 SSP
◦ Mobile applications
 GSM /GPR

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