Vidya Pratishthan’s College of Engineering
Baramati Dist Pune-413 133
Department of Electronics and Telecommunication
Engineering
A REPORT
ON
INDUSTRIAL VISIT '16
CHINCHWAD
To
The Principal,
Vidya Pratishthan’s College of Engineering, Baramati.
Subject: - Report of Industrial Visit at BSNL Exchange, Chinchwad
Respected Sir,
Department of E and TC Engineering conducted Industrial Visit at BSNL
Exchange, Chinchwad. Hereby, we are submitting the Report of Industrial Visit
which we conducted on 3 and 4 February 2016.
Report Consists of activities conducted at RTTC and BSNL Exchange
• Overview of telecommunication networks
• Visit to Transmission lab
• Visit to BTS Lab
• Visit to BSC Lab
• Visit to MSC Lab
• Visit to GMSC Lab
Visit In-charge
HoD, E and TC
Principal
Industrial tour was organized by Electronics and Telecommunication Engineering department
under the guidance of Mr. S. S. Muttagi (Assistant Professor) and Mrs. J. S. Rangole (Ho.D., E&TC.)
on 3rd and 4th February 2016 for the students of 8th semester to guide them and make them aware
about the actual field work in telecom industry. We also thank the supervisor staff at BSNL
Telephone Exchange to guide us through the entire process.
1. EVENT AT A GLANCE
Students were taken to BSNL Telecom Exchange, Chinchwad to provide them knowledge
about actual field work done in telecom companies, telecommunications networks, and to introduce
with the principles of the telecommunication industry, mobile technologies, including GSM and
CDMA, and emerging trends in telecom networking. Purpose of this visit was to provide students
with exposure to the systems and equipment used in BSNL and enhances awareness concerning job
options in the industry.
2. COMPANY PROFILE
Bharat Sanchar Nigam Limited (BSNL) is an Indian state-owned telecommunications company
headquartered in New Delhi, India. It was incorporated on 15 September 2000 and took over the
business of providing of telecom services and network management from the erstwhile Central
Government Departments of Telecom Services (DTS) and Telecom Operations (DTO), with effect
from 1 October 2000 on a going concern basis. It is the largest provider of fixed telephony, largest
broadband services provider with more than 60% Market share, and fourth largest mobile telephony
provider in India.
BSNL is India's oldest and largest communication service provider (CSP). It had a customer
base of 117 million as of January 2014. It has footprints throughout India except for the
metropolitan cities of Mumbai and New Delhi, which are managed by Mahanagar Telephone Nigam
(MTNL).
1. BTS TOWER
As per schedule we visited Ground based BTS Tower (tower height 80 mtr). There were
different types of antennas mounted on the tower. Circular shaped antenna, rectangular antenna,
parabolic antenna; circular antenna is used for microwave communication with the range of 1 km.
Another antenna was rectangular shaped which was mounted vertically with some tilt. There were 3
such antennas mounted along the same horizontal axis covering 3 different directions
(Sectorization). These antennas were unidirectional used for transmission and receiving the signals
from Mobile Station.
Antennas were implemented with optimum planning to cover radius of 5-10 Km. Each antenna
was connected with coaxial cables (feeders) for transmission & reception of the signals. Drum
antennas were used as link (microwave frequencies) to communicate with other towers. This kind
of communication is called as the mini-link communication. Apart from Ground based Tower,
different other kinds of towers can also serve the purpose:
•
•
•
•
Rooftop Telecommunication tower
Triangular Telecommunication tower
Tubular Telecommunication tower
Angular Telecommunication tower
2. BASE STATION CONTROLLER (BSC)
From BTS we visited BSC Lab. BSC stands for (Base Station Controller), and is responsible for
handling traffic and signaling between a mobile phone and network switching subsystem. As per the
GSM Architecture, single BSC handles few BTS (Base Transceiver Station). At Chinchwad
Telephone Exchange, BSCs were installed to serve 2G as well as 3G connections. BSCs used for 3G
are compact in size as compared to that of 2G BSCs. These BSCs are also connected to the Ethernet
Cables, to provide seamless connectivity through internet
BSC contains 3 connection wires one for transmission and remaining two for reception. The
rooms containing BSC’s are generally unmanned room, so as to avoid any damage due static human
charges. BSCs work on –ve 48 volt supply.BSC is responsible for the allocation of Radio Resources
to a mobile handset. Also, Handoffs are also been handled by BSC.
Transfer of data is carried out through Abis link. Digital Distribution Frame (DDF) is used to
transfer the call to their respective BTS. Data Traffic from BSC to MSC is carried through
Transcoders (TC). Ater link is used to relay the signal between BSC to TC. As per the statistics
provided by the supervisors, one BSC can handle maximum of 1900 Erlangs of traffic, and
maximum of 448 TREs.
3. MOBILE SWITCHING CENTRE (MSC)
The MSC is a telephone exchange that makes the connection between mobile users within the
network, from mobile users to the public switched telephone network and from mobile users to
other mobile networks. The MSC also administers handovers to neighboring base stations, it also
keeps a record of the location of the mobile subscribers, and is responsible for subscriber services
and billing.
MSC can be divided into few blocks as shown in the figure above, they can be as follow:
• Home Locator Register (HLR): It stores the information related to the subscriber identity.
MSC authenticate the subscriber based on the data stored in HLR.
• Visitor Locator Register (VLR): It is a part of MSC which stores the current location of the
subscriber. VLR is responsible for Roaming.
• Equipment Identity Register (EIR): It is a registry which stores IMEI information from the
mobile subscriber. Entry in EIR is used during call setup procedure.
4. GATEWAY MOBILE SWITCHING CENTRE (GMSC)
The GMSC is a special kind of MSC that is used to route calls outside the mobile network.
Whenever a call for a mobile subscriber comes from outside the mobile network or the subscriber
wants to make a call to somebody outside the mobile network the call is routed through the GMSC.
In practice, the GMSC is just a function that can be part of a MSC.
OUTCOME OF VISIT
“See & know, is better motto than, read & learn”
Students understood the basic working of MSC and BSC. Visit has resulted into
enhanced learning process. During the visit students observed the practical
implementations of syllabus. Apart from this, they gained the knowledge related to
the building architecture of tower, room temperature and safety. Thus this visit was
accomplished satisfactorily.