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INDUSTRIAL TRAINING
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1. Block diagram of cellular communication
2. About BTS
3. About BSC
4. About MSC
5. MODEMS
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Block diagram of cellular communication
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When the subscriber makes the call the
signal reaches the nearest BTS. BTS is nothing but a tower
From BTS the signal reaches the BSC
(exchange) Through BSC it is forwarded to MSC
In MSC switching takes place and the
same process reversed to reach thedestination
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BTS means BASE TRANSCEIVER STATION
BTS is a network component from which allthe signals are transferred and received
It is also called as a base station and
commonly referred as Cell Phone Tower orRadio Base Station
It is applicable in wireless communication
technologies like GSM, CDMA etc
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Various parts of BTS
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There are 4 types of cards
1. Power card2. Control card
3. Alarm card
4. CTU
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POWER CARD
There are 4 power cards in BTS
The basic function is to supply power to allother cards
The input power supply to these cards in48v dc
Output voltage is divided as perrequirement of other cards
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CONTROL CARDS
It controls the function of all other cards
It has another duplicate card
Duplicate card works when the main cardsfails working
It requires the power supply of 5v, 12v,
24v dc
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ALARM CARD
It requires the power supply of 5v, 12v,24v dc
It works as an indicator
It produces alarms during unconditional
situations like> change in temperature
> change in input voltage
> damage in other cards
> over load. Etc
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CTU
CTU means compact transceiver unit
It is the main card in BTS which monitors thesignal
It consists of 4 slots
In each slot 8 channels are present
In them 1 channel is dedicated for alert
signaling and interference between channels Remaining 7 channels can be used at a time
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BSC
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BSC stands for Base Station Controller
It is nothing but an exchange
Several BTS are connected to BSC Through BTS a 2Mbps cable is
connected to BSC
It works as a concentrator where manyconnections from BTS is reduced tosmaller no of connections to MSC
It provides all controlling functions andlinks between switching switch & basestation
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It is responsible for handling and
signaling between mobile phones The output of BSC signal is 16Kbps
MSC
MSC means mobile switching center
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Before MSC the signal enters to thetranscoder
TRANSCODER
Transcoding is the process of taking a audiofile and changing it to a bit rate
It converts the audio signal into 64Kbps
signal
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MAIN MSC
It is basically CPU of mobile network
It controls calls to and from othertelephones
It co-ordinates several BSC
It provides billing information
It co-ordinates the location updates ofmobile subscribers
In MSC switching takes place andsends to corresponding BSC & BTS andfinally to destination
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MODEMS A modem is nothing but a modulator-
demodulator
It is the device which modulates the digitaldata into analog data at transmitter
And it also demodulates the digital informationto analog information at receiver
The main goal is to produce a signal that canbe transmitted and reproduced the signaleasily
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TYPES OF MODEMS Modems are divided into two types :
1. Landline Modems2. Wireless Modems
LANDLINE MODEMS
They are connected to the publicswitched telephone network. To connectthe PSTN a telephone cable is used
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Through exchange a telephone line isallocated to the modem
The signal from exchange consists ofboth analog data and voice
To split both a splitter is connected
The voice signal is connected totelephone
The analog data is connected to
modem Modem demodulates the analog into
digital and connected to PC
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WIRELESS MODEMS
Wireless modems are radiotransmitters/receivers installed intomobile computing devices
They are connected to laptops, mobilephones etc
The best example of wireless modems is the
Wi-Fi connection
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Wi-Fi In wireless network an adapter or USB is
connected to the laptop of computer
A wireless network uses radio waves just likecell phones, televisions and radios.
A computer's wireless adapter translatesdigital data into a radio signal and transmits itusing an antenna.
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The router receives the radio signal anddecodes it into digital data
After processing the signal the router againtranslating it into a radio signal and send itto the computer's wireless adapter
The router sends the information to theInternet using a physical, wired Ethernetconnection.
Ethernet is a standard cable which used tolink the computer to the internet
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Router & adaptor can transmit and receiveradio waves, and they can convert 1s and 0s
into radio waves and convert the radio wavesback into 1s and 0s.
The WiFi communication are very similar tocell phones.
But they transmit at frequencies of 2.4 GHz or5 GHz. The higher frequency allows thesignal to carry more data.
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