Mobile Technologies

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Switching on a Mobile Phone

  • Mobile phone uses low intensity microwave signals in order to transmit and receive voice and data information.
  • The mobile phone transmits radio signals when switched on enabling it to broadcast its radio location so that calls can be diverted to it. Mobile phones communicate using a network of cells to transmit data
  • When a phone is powered up it listens for an SID on the control panel. The SID is the System Identification Code.
  • This code is unique and is assigned to each network provider.
  • If the phone cannot find any channels to listen to, it knows that it is out of range and displays a "no service message". When the phone recieves an SID it compares it to the SID programmed into it's hardware. If the two SIDs match, the phone knows it has connected to it's home network.
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Making a Call on a Mobile Phone

  • When a mobile phone call is made, the microphone within the mobile phone picks up the voice signal and a microchip converts it into a radio wave signal so that it can be transmitted over the mobile network.
  • The phone's antennae will broadcast this signal to the nearest mobile phone mast which receives the signal and transmits it to its base station.
  • The area over which the base station has control is known as a cell and the base station will co-ordinate the transmission of the signal across the cell.
  • Phone calls made from one mobile to another on the same network will be routed through base stations until they arrive at the destination phone. Phone calls made to mobile phones on a different network may take a lengthier route
  • The radio transmitter and receiver contained within a mobile phone itself are not capable of transmitting signals over long distances
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Network Coverage

  • The area where you live is divided up into smaller areas, each area served by its own masts and base station, referred to as cells and hexagon in shape.
  • Cell masts and base stations are placed strategically to ensure maximum cell coverage.
  • As a user moves across a city during a call, they will move between cells, therefore the call must be transferred from one cell to another smoothly.
  • The network automatically switches coverage responsibility from one base station to another through a process called handoff
  • The use of cells means that the system can handle many more calls at once, because each cell uses the same set of frequencies as the cells located close to it. The more cells, the greater the number of calls that can be made at once.
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Mobile Switching Center

  • Mobile phones can also be used to make calls to landlines
  • A mobile switching centre carries out switching functions, such as call set-up, release and routing. 
  • It also routes other services such as SMS messages and conference calls as well as interfacing with the public switched telephone network.
  • The MSC allows base stations to connect to it, while it connects to the PSTN
  • This enables all forms of communication, whether between two mobile phones or a mobile and a landline.
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Comments

Alexia48

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Great and useful info! Thanks for sharing with us!

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