For most of us, Mobile phones are a part of our lives and we use it everyday to make and receive calls.....
Have you ever wondered how a mobile phone receives or establishes a call???
IF YES, CONTINUE READING
I'll be giving steps that takes place when establishing a phone call on moble.
Before going into the steps, you need to know some of the terms used in communication systems!
They include:-
¶ BASE-STATION; this is not the cellphone mast we see everywhere.
A mast is the metal thing that holds the antennas while the base-station is the element that the antennas feed into, that then talks to the world.
¶ CONTROL CHANNEL; is a radio channel used for transmission of control signals.
¶ VOICE CHANNEL; is a radio channel used for transmission of voice signals.
¶ REVERSE CHANNEL; is a radio channel used for transmission of information from mobile phones to the base station.
Before a phone can establish a call, it establishes connection to the service provider's network. E.g. (MTN)
THE STEPS INVOLVED IN ESTABLISHING A MOBILE PHONE CALL INCLUDES:-
¶ A call initiation request is sent on the reverse control channel, the phone also sends its mobile identification no (MIN) with the request, it also sends the electronic serial no and the dialled phone no.
¶ The base station receives the data and sends to the mobile switching center that will check for validity, if valid, a connection to the call party is made.
¶ A request is then sent to the base station to move the caller to an unused voice channel so that conversation can begin.
When a call is made and there is no free voice channel, that's when you hear "network busy". This indicates that large no of calls are made from the coverage area of the base station.
NOTE:- All this happens within few seconds that we almost start hearing the ring tone as soon as a no is dialled.
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