TATA TELESERVICES LTD, NOIDA.
MILAN KUMAR GUPTA
VTH SEMESTER (3RD YEAR)
B.Tech. (ELECTRONICS & COMMUNICATION)
Tata Group is an Indian multinational conglomerate company headquartered in
the Bombay House in Mumbai, India. In terms of market capitalization and
revenues, Tata Group is the largest private corporate group in India. It has
interests in communications and information technology, engineering, materials,
services, energy, consumer products and chemicals. The Tata Group has
operations in more than 80 countries across six continents and its companies
export products and services to 80 nations. The Tata Group comprises 114
companies and subsidiaries in eight business sectors, 27 of which are publicly
listed. 65.8% of the ownership of Tata Group is held in charitable trusts.
Companies which form a major part of the group include Tata
Steel (including Tata Steel Europe), Tata Motors (including Jaguar and Land
Rover), Tata Consultancy Services, Tata Technologies, Tata
Tea(including Tetley), Tata Chemicals, Industries, Tata, Tata
Communications, Tata Sons, Tata Teleservices and the Taj Hotels.
•TATA LEADERSHIP IN DIVERSE INDUSTRIES
•The world's largest integrated tea operation-Tata Tea
•Asia’s largest software exporter-TCS
•The world’ sixth largest manufacturer of watches –Titan
•India’s largest private sector steel producer-Tata Steel
•Largest 5-star chain of luxury hotels in India-Indian Hotels
•India’s largest manufacturer of soda ash-Tata Chemical
•TATA Motors is leading company of the world
INTRODUCTION TO CELLULAR GROWTH
FATHER OF TELEPHONE: Alexander Graham Bell
IN 1876, Alexander Graham Bell patented his telephone, a device for
carrying actual voice over wires the term cellular usually refers to wireless
service that uses the 850 MHz block of frequencies. The term mobile refers to
any wireless telephone. The terms mobile user and cellular user are synonymous.
Various Mobile Technologies
CDMA(Code Division Multiple Access)
In the CDMA scheme, the digital information from each user is allowed to access the system
simultaneously (as each user requests) using the same frequency spectrum. Frequency
division is still used, but a large bandwidth is used for each carrier. A user “channel” in
CDMA is defined by a specific code and an associated carrier frequency. The user code is
correlated against the receive signal to recover only the information specific to that user. The
capacity of a CDMA system is governed by the amount of interference in the environment
that the receiver can tolerate before it is unable to recover the desired user information.
Third generation (3G) networks were conceived from the Universal Mobile
Telecommunications Service (UMTS) concept for high speed networks for enabling a variety
of data intensive applications. 3G systems consist of the two main standards, CDMA2000 and
2G 3G 3.5G
GSM CDMA ONE UMTS CDMA 2000 UMTS
1X(for Voice only) 3X(Data+Voice) EVDO/HSIA
Multiple Access Techniques FDMA+TDMA CDMA WCDMA CDMA WCDMA
TATA Products Tata Dokomo Tata Indicom Tata Photon+ Tata Dokomo
Max.Speed(Kbps) 9.6 9.6 307.2 2 3.1 21
Bandwidth(Tata) 8.8MHz 10MHz 10MHz 10MHz
Frequency Band(Tata) 1800MHz 850MHz 850MHz
Uplink 835.455-840.375MHz 835.455-840.375MHz
Downlink 880.455-885.375MHz 880.455-885.375MHz
Bandwidth (per user) 200KHz 1.23MHz 5MHz 1.23MHz 5MHz
Modulation Techniques GMSK QPSK/OQPSK QPSK/BPSK QPSK/OQPSK QPSK,(16-,64) QAM/4-PAM
GSM Vs CDMA
What is the difference between GSM and CDMA? The comparison of GSM vs CDMA is very
useful and interesting from buyer's as well as student's perspective. The following article on
GSM vs CDMA will help you to understand the differences between these two technologies.
Call Quality: This is an area where CDMA scores substantially over GSM. Statistics are
hugely in favor of CDMA. Various factors such as echoes, call dropping, or voice distortion
are almost non-existent in CDMA, whereas in GSM, there is a high probability of errors. To
give you an analogy, the bus on the street will continue to ply even when it's full, but if the
honeycomb has reached full capacity, the honey cannot be deposited.
GSM vs CDMA Call Qality Score: CDMA scores. Goal count 0-1.
Carriers: GSM is one up on CDMA as far as carriers are concerned. The law requires
CDMA carriers to provide handsets to users, for which the users cannot change their
carriers. Whereas, GSM users can change their carriers whenever they want.
GSM vs CDMA Carriers Score: GSM scores. Goal count 1-1.
Network: It's an on-going battle between the two. Both the technologies are
continuously improving the qualities of their network and adding various aspects to it as
GSM vs CDMA Network Score: Both score. Goal count 2-2.
Worldwide: There is a special number that every GSM compatible device in the
world can call in case of an emergency. That number is 112. But in CDMA, this cannot be
implemented because of certain technological limitations.
GSM vs CDMA Worldwide Score: GSM scores. Goal count 3-2
Battery Life: GSM, being a relatively simpler technology, uses less amount of cell
phone battery than CDMA.
GSM vs CDMA Battery Life Score: GSM scores. Goal count 4-2
Coverage: GSM and CDMA, both have similar network coverage areas. They are
present almost everywhere. The service providers of both technologies are striving hard to
cover whatever inches that are left.
GSM vs CDMA Coverage Score: Both score. Goal count 5-3
Speed: Both GSM and CDMA are rapidly improving their capabilities in this regard.
Both have introduced 3G mobile phones in their fold. Both are competing to gain space in
GSM vs CDMA Speed Score: Both score. Goal count 6-4
Building Penetration: Again, in initial days, both technologies couldn't find
building penetration, but after research in signaling systems, and through experience,
service providers of both technologies have been able to give decent service to the mobile
phones in buildings.
GSM vs CDMA Penetration Score: Both score. Goal count 7-5
GSM vs CDMA: Which is Better?
Both have their good qualities and bad qualities. GSM has some limitations where call
quality is concerned, but GSM can be easily implemented and easily integrated into
existing technology. Whereas, CDMA is little difficult to implement. By my estimation,
GSM has an upper hand. So, the answer to the question, "GSM vs CDMA which is better?"
is GSM. More on:
(Global System for Mobile
WHAT IS GSM
GSM is a 2G technology that was developed to solve the fragmentation
GSM is the world’s first cellular system to specify digital modulation.
It is a most popular 2G technology.
To allow roaming within European countries.
To allow interaction with ISDN(Integrated Service Data Network).
SIM (Subscriber Identity Module) :
SIM is a memory device that stores information such as Subscribers
identification number, Privacy keys & User specific information.
SIM has 4 digits PIN which subscriber must key in to activate service from any
Called number is not associated with MS but is linked to the SIM.
Control of transmission power.
Mobile Assisted Hand over (MAHO).
Support of Short Message Service (SMS).
Base Station Switching Public
Subsystem Subsystem Networks
HLR VLR AUC
BTS BSC PSTN
BTS BSC Network
BTS OMC Support
GSM Architecture consists of four major parts.
1. Mobile Station (MS).
2. Base Station Subsystem (BSS).
3. Network & Switching Subsystem.
4. Operation Support Subsystem.
1. Mobile Station (MS):
The MS consists of Mobile Equipment (ME) & SIM.
At the time of manufacture, an International Mobile Equipment Identity (IMEI) is
programmed into ME.
A SIM is required to activate GSM ME.
The International Mobile Subscriber Identity (IMSI) is programmed into SIM along
with security parameters & algorithms.
The called number is not linked to ME but to SIM.
2. Base Station Subsystem (BSS):
The BSS consists of
A. Base Station Controller (BSC).
B. Base Transceiver Station (BTS).
A. Channel Management.
Configuration of channel with respect to use as speech, data or signaling
Selection, allocation & release of channel.
Monitoring of channel.
B. Frequency Hopping & power control.
Assignment of frequency hops sequence & start time.
Assignment of Effective Radiated Power values to mobile stations.
C. Handoff Management.
Collect signal quality data from adjacent BSSs.
Analyze signal quality data & determine when to handoff.
Keep MSC informed regarding handoff activity
3. Network & Switching Subsystem.
The NSS consists of
A. Mobile Switching Center (MSC).
B. HLR database.
C. VLR database.
D. AuC database.
A. Mobile Switching Center (MSC).
It handles the switching of GSM calls between external networks (PSTN, ISDN)
Call setup, supervision and release.
Billing information collection.
Paging & alerting.
Management of radio resources during call.
Manage connections to BSS, other MSCs & PSTN/ISDN.
Interrogation of appropriate registers.
B. Home Location Register (HLR).
The HLR is centralized database that holds permanent data of mobile
Generally one HLR per operator.
The HLR is kept updated with the current locations of subscribers, including
those who may have roamed to another network operator within or outside country.
HLR maintains following database.
2. Service subscription information.
3. Service restrictions.
4. Supplementary services subscribed.
5. Mobile terminal characteristics.
6. Billing/Accounting information
C. Visitor Location Register (VLR).
The VLR is a database which temporarily stores the IMSI & customer information
for each roaming subscriber who is visiting the coverage area of a particular MSC.
Generally one VLR per MSC.
VLR maintains following database.
1. Features currently activated.
2. Temporary Mobile Station Identity.
3. Current location info about MS.
Once roaming subscriber logged in the VLR, the MSC sends necessary
information to the visiting subscribers HLR so that calls to the roaming mobile can
be routed over the PSTN by the roaming users HLR.
Even if the subscriber is in the area covered by its home MSC, it is entered in
that particular VLR.
D. Authentication Centre (AuC).
As the radio interface and mobile stations are very vulnerable to malicious
misuse, a separate Authentication Centre (AuC) has been defined to protect user
identity and data transmission.
The authentication centre is strongly protected database which is generally
associated with HLR.
It contains algorithm for authentication as well as keys for encryption and
generates the values needed for user authentication in the HLR.
E. Equipment Identity Register (EIR).
The authentication centre contains a register called the EIR.
The EIR maintains information to authenticate terminal equipment so that fraud,
stolen terminals can be identified and denied services.
The information is in the form of White (valid terminal), Gray (Malfunctioning
terminals) & Black (Stolen terminals).
4. Operation Support Subsystem (OSS).
The OSS supports one or several Operations Maintains Centers (OMCs) which
are used to monitor & maintain the performance of each MS, BSC, & MSC within a
The OMC also has provision for adjusting all base station parameters & billing
procedures, as well as for providing system operators with the ability to determine
the performance & integrity of each piece of equipment in the system.
A bis Interface A Interface SS7
BTS BSC MSC PSTN
1. Air Interface:
The Air Interface is the common radio interface between the MS& BTS enabling
communication between MS & BTS.
2. A-bis Interface:
The A-bis interface connects a BTS to BSC.
It carries traffic & maintenance data.
It is standardized by GSM for all manufacturers.
However the A-bis for all GSM manufacturers have small differences, thereby
forcing service providers to use the same manufacturer for the BTS & BSC
3. A Interface:
The A Interface connects BSC & MSC.
A Interface is standardized by GSM & uses SS7 protocol.
A Interface allows service provider to use BTS & MSC from different manufacturer.