What Is The Cellular Network
A cellular
network or mobile network is a communication network where the
last link is wireless. The network is distributed over land areas called cells,
each served by at least one fixed-location transceiver,
but more normally three cell
sites or base
transceiver stations. These base stations provide the cell with the
network coverage which can be used for transmission of voice, data, and other
types of content. A cell typically uses a different set of frequencies from
neighboring cells, to avoid interference and provide guaranteed service quality
within each cell.
When joined together, these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers. (e.g., mobile phones, tablets and laptops equipped with mobile broadband modems, pagers, etc. ) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission.
Cellular networks offer a number of desirable
features :
- More capacity than a single large transmitter, since the same frequency can be used for multiple links as long as they are in different cells.
- Mobile devices use less power than with a single transmitter or satellite since the cell towers are closer.
- Larger coverage area than a single terrestrial transmitter, since additional cell towers can be added indefinitely and are not limited by the horizon.
Major telecommunications providers have deployed voice and data cellular networks over most of the inhabited land area of Earth. This allows mobile phones and mobile computing devices to be connected to the public switched telephone network and public Internet. Private cellular networks can be used for research or for large organizations and fleets, such as dispatch for local public safety agencies or a taxicab company.
Mobile Searching Centre
Cellular networks maintain information for tracking the location of their subscribers' mobile devices. In response, cellular devices are also equipped with the details of appropriate channels for signals from the cellular network systems. These channels are categorized into two fields :
Strong Dedicated Control Channel
- Used to transmit digital information to a cellular mobile phone from the base station and vice versa.
Strong Paging Channel
Strong Paging Channel
- Used for tracking the mobile phone by MSC (Mobile Switching Centre) when a call is routed to it.
A typical cell site offers geographical coverage of between 9 and 21 miles. The base station is responsible for monitoring the level of the signals when a call is made from a mobile phone. When the user moves away from the geographical coverage area of the base station, the signal level may fall. This can cause a base station to make a request to the MSC (Mobile Switching Centre) to transfer the control to another base station that is receiving the strongest signals without notifying the subscriber. (this phenomenon is called handover). Cellular networks often encounter environmental interruptions like a moving tower crane, overhead power cables, or the frequencies of other devices.
References
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