Submited By:-
GURUDAYAL SINGH BHANDARI

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Bharat Sanchar Nigam Limited Area Exchange, Bhopal On GSM Architecture
About the Bharat Sanchar Nigam Limited
“BHARAT SANCHAR NIGAM LIMITED” is abbreviated as BSNL. It is fourth
largest departement of TeleCommunication Company in Asia and seventh in
world today. Which is one of the most earning revenue in India. Above more than
3 laces employees, officer and engineers working in BSNL at present.
It was 31 march 2002 when BSNL started GSM mobile and
today it has provided almost 35 lacks mobiles in all over M.P.
WLL system which is also a mobile with limited mobility in city & can have Tele communication facility in that area almost. While GSM can cover
all cities of the country.
SCOPE OF TRAINING
Training is one of the essential parts of engineering studies as it provides us confidence and exposure to the real world problem. In my training I used my learned skills and saw how things work in real world. Now we are quite confident about our fundamentals as we have tested them during our project and have gained experience of working with discipline. Practical training provides us a view of professional and prepares us to face the upcoming challenges.
After achieving the proper goal of the engineer has enter in professional life. According to this life one has to serve an industry, may be public or private or self own. for the efficient work in the field he must be well aware of practical knowledge as well as theoretical knowledge. Since we belong to the electronic field it is really helpful to take training at a place that clears a doubt and inquisitively regarding.
INTRODUCTION TO GSM
GSM is known as Global System for Mobile Communication. A technology developed in 1985 by a French company known as Group Special Mobile.
Cellular radio provides mobile telephone service by employing a network of cell sites distributed over a wide range. A cell site contains a radio transceiver and a base station controller, which manages, sends, and receives traffic from the mobiles in its geographical area to a cellular phone switch. It also employs a tower and its antennas, and provides a page link to the distant cellular switch called a mobile telecommunication switching office. This MTSO places calls from land based telephones to the wireless customers, switches calls between cells as mobile travel across cell boundaries, and authenticates wireless customers before they make calls.
GSM calls are either based on data or voice. Voice calls use audio codes called half-rate, full-rate and enhanced full-rate. Data calls can turn the cell phone into a modem operating at 9600 bps.
It uses digital technology and time division multiple access transmission methods.
Voice is digitally encoded via a unique encoder, which emulates the characteristics of human speech. This method of transmission permits a very efficient data rate/information content ratio.
One of its great strength is the international roaming capability that gives consumers seamless and same standardized same number contact ability in more than 170 countries. GSM satellite roaming has extended service access to areas where terrestrial coverage is not available.
GSM technology is continually evolving. Having made great leaps forward in the past 10 years. It is facing an even greater evolution in the years ahead.
HISTORY OF GSM
The first mobile telephone service started in 1946 in St. Louis, Missouri, USA as an manually operated system. Between 1950 and 1960, it evolved as an automatic system with reduced cost and increased, but small subscriber base. Mobile telephony service in its useful form appeared in 1960s.
The period from 1940 – 60
• The 1st mobile telephone service started in 1946 in St. Louis Missouri, USA.
• Between 1950 and 1960 it evolved as an automatic system.
• Mobile telephony service in its useful from appeared in 1960s.
The period from 1980 - 95
• Each country developed its own system
• In 1982 the Conference of European Posts and Telegraphs (CEPT) formed a study group called the Group Special Mobile (GSM) to study and develop a European public land mobile system which had to meet certain criteria :
Good subjective speech quality.
Low terminal and service cost.
Support for international roaming
Ability to support hand held terminals.
Support for range of new service and facilities.
Spectral efficiency.
In 1989, GSM responsibility was transferred to European Telecommunication Standards Institute (ETSI)
GSM specifications were published in 1990 as:-
Commercial service started in mid – 1991
By 1993 there were 36 GSM networks in 22 countries
The First Generation Mobile Communication System appeared in 1970s and remained till 1980s.They used analog transmission techniques for radio page link and confined its users to their respective systems areas for which the mobile phone was designed. Capacity of system was limited and roaming between the coverage areas of different systems was impossible. Apart from being very expensive these system provides very poor QoS and supported only voice communication.
The Second Generation Mobile Communication System has grew out of the limitation of first generation systems. They supported large subscriber base, carried both voice and data and have capable of design and deliver new value added services. GSM and CDMA emerged as the trend setting technologies. The domination of 2G systems became apparent in second half of 1990s.
The Third Generation Mobile Communication Systems provide high functionality with seamless global roaming. Apart from providing very high data rates, 3G systems seek to integrate the wire line systems with mobile systems. 3G would provide users consistent voice, data, graphical, multi-media regardless of their location in the network. They also integrate the Intelligent Network (IN) capabilities intinto mobile systems.
Cellular Principal And Mobility Issues: -
In mobile communication the wired 2W subscriber line is replaced with a wireless mobile link. Once the customer is liberated from the confines of the wire and made free to move, the following issues arise :-
• Demand on the scarce radio resources.
• Authentication of the customer.
• Security and privacy on the radio
• Provide unique service profile.
• Keep track of the user as they move.
• Proving service across networks.
• Billing the customer whenever and wherever he makes and receives calls from.
An important issue in mobile communication is the need to authenticate the genuineness of the customer whenever he receives or attempts to make communication. Since the media being open space, it is necessary to verify whether the customer is the one whom he claims to be before resources allocation. Security of the mobile account is to be ensured to prevent unauthorized use and also misuse of one’s subscription. Privacy of the communication over radio is to be ensured though the radio signals are available everywhere for interception.
One of the important issues for the customer is the availability of seamless service profile irrespective of his location. This is an essential feature of the mobile communication, particularly when the customer visits a service area served by an operator different from his own. Different dialing codes for accessing the same service in different networks can lay havoc in realizing the services by the customer.