Niharika Presentation

7/31/2019 Niharika Presentation

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A

SUMMER TRAINING

PRESENTATION

ONCDMA TECHNOLOGY

FROM

TATA TELE SERVICES LIMITED

LUCKNOWSUBMITTED BY

NIHARIKA

EC. 4TH YEAR


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TATA is a name synonymous with quality and the highest standards. The company started off with

its founder Jamshed ji Tata setting up the first steel plants in India. Over a period of more than 100

years the company has grown making forays into a wide variety of businesses.

Today the company is a trendsetter across markets and segments. The group is radically innovatingand reinterpreting the meaning of growth. The latest in a long line of path-breaking achievements by

the company is the launch of TATA-TELESERVICES LIMITED or TTSL, which is the

backbone behind the hugely successful telecom brand, TATA INDICOM.


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The process by which multiple signals are transmitted over the same

channel at the same time is called multiplexing.

The various types of multiplexing techniques are:

FDMA


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TDMA


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CDMA


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TELEPHONE

In telephone the voice signal is converted to an electronic signal bythe microphone in the handset. This signal is then transmitted overtelephone wires.

A telephone is a device that is capable of transmitting and receivingat the same time. Devices that can transmit and receive at the sametime are called full duplex devices.

MOBILE TELEPHONES

In mobile telephones signals are broadcasted through air rather thantransmitting through wires.

For covering a large area, very powerful transmitters and very highantenna towers were required.


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Wireless communication systems use E&M waves to transmit

signals through the air. When subscribers share the same frequencythey will create interference. it the invention of the radio, expensivecabling requirements were eliminated and transoceanic wirelesscommunication became possible. Radio was invented by Marconian Italian scientist in 1895. In radio communication the informationsignal is converted into an electromagnetic wave form and isbroadcast in space using radiating devices known as antennas

The resource: Frequency

The problem: Interference

The solutions: Multiple Access Techniques


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CDMA is a multiple access direct sequence spreadspectrum modulation technique. It takes narrow bandinformation (10 kHz) from user and transmits it over awide RF bandwidth (1.23 MHz).CDMA uses correlative

codes to distinguish each individual user in the system.

CDMA employs analog-to-digital conversion (ADC) incombination with spread spectrum technology. Audioinput is first digitized into binary elements. The

frequency of the transmitted signal is then made to varyaccording to a defined pattern (code), so it can beintercepted only by a receiver whose frequency responseis programmed with the same code, so it follows exactlyalong with the transmitter frequency.


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CDMA one is also known as IS-95 (InterimStandard -95).IS-95 is the mobile station basestation compatibility standard for Dual-mode

Wideband Spread Spectrum Cellular. It is also known as the CDMA Air Interface

specification.

For PCS (Personal Computer System), interimStandard-95-A is employed. It has a maximumdata rate of 14.4 kbps whereas IS-95 specifies amaximum data rate of 9.6 kbps.


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Mobile StationMSThe Mobile is the hardware used by the subscriber toaccess the cellular network.

Two main types of MS:-

Vehicle Mounted: These devices are mounted in avehicle and the antenna is physically mounted on theoutside of the vehicle.

Hand portable Unit: This equipment comprises of asmall telephone handset not much bigger than acalculator. The antenna is connected to the handset.


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Functions of BSC are:

Call control processes

Database of subscribers Record calls for billing

Switch the calls to PSTN


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The mobile switching center (MSC) is the primary service

for handling voice calls and SMS as well as other. The MSC

sets up and releases the end-to-end connection, handles

mobility and hand-over requirements during the call and takescare of charging and real time pre-paid account monitoring


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Handoff describes the process of transferring a call

from one cell to another.

As the phone moves through a network, the system

controller transfers the call from one cell to another,

this process is called Handoff.

TYPES OF HANDOFF

HARD HANDOFF

SOFT HANDOFF


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In cellular service there are two main competingnetwork technologies:

Global System for Mobile Communications (GSM)

Code Division Multiple Access (CDMA)

1- DATA TRANSFER SPEED2-SUBSCRIBER IDENTITY MODULE (SIM)

CARDS:3-ROAMING4-SPEECH QUALITY5-CAPACITY AND SPECTRAL EFFICIENCY6-DATA CAPABILITY


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