This document provides an overview of Anusha Srivastava's industrial training at the Advanced Level Telecom Training Centre (ALTTC) in Ghaziabad, India. It discusses the history and mission of ALTTC. The document then summarizes key concepts in telecommunications including the basic working of telecom networks, switching, public switched telephone networks, multiple access techniques, GSM network architecture and components, IP addressing, fiber optic transmission systems, CDMA, and references used.

1. A Presentation
based on
Industrial Training in ALTTC, Ghaziabad
on
TELE-COMMUNICATION
Submitted by:
Anusha Srivastava
ECE 4th year
R.K.G.I.T, Ghaziabad
Guided by:
Om Pal Singh
S.D.E,
ALTTC, Ghaziabad

2. About ALTTC
Advanced Level Telecom Training Centre
Advanced Level Telecom Training Centre (ALTTC), Ghaziabad is the apex training
institute of BSNL. An ISO 9001: 2008 accredited institute, ALTTC was set up as a
joint venture of International Telecommunication Union, Geneva, UNDP and the
Government of India in 1975. ALTTC functions on the frontiers of telecom
technology, finance and management and imparts training to the leaders in the
business. The strength of ALTTC lies in the state of art labs, massive infrastructure
and trained, talented and qualified human resource pool.
The Centre'sMission statement is "To Deliver Excellence Through Training".
The training areas cover vast spectrum of topics such as Digital Switching and IN;
Mobile Communication: GSM, 3G, CDMA; Data communication and Information
Technology: MPLS, VPN, Broadband, IPv6, Database Administration, Server
Administartion, IT Security; Optical Networks: SDH, DWDM, NGSDH, NGN, Access
Networks, Management, Telecom Finance, Building Science (Civil and Electrical) and
Telecom Network Planning 2

3. What is Telecommunication
Telecommunication is communication at a distance by technological means,
particularly through electrical signals or electromagnetic waves.
3

4. WORKING OF BASIC TELECOMMUNICATION
NETWORK
CALL SETUP:
When a subscriber calls to another subscriber first its request goes to
the nearest switching center that is PSTN (Public Switching
Telecommunication Network). Then it processes the caller and
subscriber’s number if it exists in the same BSC (Base Station
Controller) then call setup is completed.
If subscriber is not in the same BSC then call transfer to MSC (Mobile
Switching Centre) then it transfers the call to prior BSC then call setup
is completed.
If Caller calls to a mobile subscriber then call transfer is done by
MTSO(Mobile Telephone Switching Office)
now call transfer is done on BTS (Base Transceiver Station) and call
setup is completed.

6. Switching
Switching is basically establishing a temporary path or connection
between two points or it can also be defined as writing at one point of
time and reading at another point of time. There are two modes of
switching employed in our network.
• Circuit Switching
•Packet Switching
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7. PSTN (Public Switched Telephone Network)
The public switched telephone network (PSTN) is the aggregate of the
world's circuit-switched telephone networks that are operated by national,
regional, or local telephone operators, providing infrastructure and services
for public telecommunication.
7

8. Multiple Access
FDMA Frequency Division Multiple Access
• Each user on a different frequency
• A channel is a frequency
TDMA Time Division Multiple Access
• Each user on a different window period in time (“time slot”)
• A channel is a specific time slot on a specific frequency
CDMA Code Division Multiple Access
• A channel is a unique code pattern
• Each user uses the same frequency all the time, but mixed with different
distinguishing code patterns
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9. 9

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

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

13. • It is responsible for allocation of
radio channels.
•Operates frequency
administration
•power and signal measurements
from the Mobile station.
•handovers from one BTS to
another.

14. •It is responsible for call routing,
call setup, and basic switching
functions.
•Different BSCs are connected to
the MSC.
• Inner-BSC handoffs as well as
coordinates with other MSC's for
inter-MSC handoffs.

15. DATABASES
 HLR(Home Location Register )
maintains subscriber specific
information such as the
MS,ISDN(Integrated Services
Digital Network), IMSI, current
location
of the MS, roaming restrictions.
 VLR(Visitor Location Register ) is a
database that contains a subset of the
information
located on the HLR.

16. IP ADDRESSINNG
• Each host on a TCP/IP network is uniquely identified at the IP
layer with an address.
• An Internet Protocol (IP) address specifies the location of a
host or client on the Internet.
• The IP address is also known as Protocol address
• The IPv4 address is 32 bits long
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17. iPv4 Address Scheme
17
•In decimal the address range is 0.0.0.0 to
255.255.255.255
•The IP address is of the form <networkID,hostID>

18. FIBER OPTICS TRANSMISSION SYSTEM
FIBER OPTICS: The use and demand for optical fiber has grown tremendously
and optical-fiber applications are numerous. Telecommunication applications are
widespread, ranging from global networks to desktop computers. These involve
the transmission of voice, data, or video over distances of less than a meter to
hundreds of kilometers, using one of a few standard fiber designs in one of several
cable designs.
ADVANTAGES OF FIBRE OPTICS :
Fiber Optics has the following advantages :
• SPEED: Fiber optic networks operate at high speeds - up into the gigabits
• BANDWIDTH: large carrying capacity
• DISTANCE: Signals can be transmitted further without needing to be
"refreshed" or strengthened.
• RESISTANCE: Greater resistance to electromagnetic noise such as radios,
motors or other nearby cables.
• MAINTENANCE: Fiber optic cables costs much less to maintain.

19. OPTICAL FIBER CABLE(OFC)
Optical Fiber is new medium, in which information (voice, Data or Video) is
transmitted on the principle of Total Internal Reflection through a glass or plastic fiber,
in the form of light.
In the following sequence.
1.Information is encoded into Electrical Signals.
2.Electrical Signals are converted into light Signals.
3.Light Travels down the Fiber.
4.A Detector Changes the Light Signals into Electrical Signals.
5.Electrical Signals are decoded into Information.

20. In wireless communication every region is divided into cells.
Cell size is constant for whole system. GSM is a form of
multiplexing, which divides the available bandwidth among the
different channels. Most of the times the multiplexing used is
either TDM (Time division multiplexing) or FDM (Frequency
Division Multiplexing). SM differs from its predecessor
technologies in that both signaling and speech channels are
digital, and thus GSM is considered a second generation (2G)
mobile phone system.

21. • 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.

22. CODE DIVISION MULTIPLE ACCESS (CDMA)
Code Division Multiple Access (CDMA) consistently provides better
capacity for voice and data communications that other commercial mobile
technologies, allowing more subscribers to connect at any given time, and
it is the common platform on which 3G technologies are built.
CDMA is a spread spectrum technology, allowing many users to occupy
the same time and frequency allocations in a given band/space
ADVANTAGES OF CDMA:
Increased cellular communications security
Simultaneous conversations
Low power requirements and little cell-to-cell coordination needed by
operators.
Extended reach-beneficial to rural users situated far from cells.

23. REFERENCES
1. Data Communication And Networking- Behrouz A. Foruzan
2. Wireless Communication and Networks-William Stallings
3. Computer Networking – Kurose & Ross
4. www.bsnl.co.in
5. www.newbsnl.co.in