The main difference between a standard telephone and a mobile phone is that a standard telephone converts the sound waves of your voice into electrical signals which are sent along telephone lines and a mobile phone converts the sound waves of your voice into radio waves which are transmitted through the air. Both types of phones require a transmission network. Base stations connect mobile phones to the communication system Base stations consist of a number of antennas that both transmit and receive signals from mobile phones. These antennas are mounted on towers, or on the sides or roofs of tall buildings. After receiving the signal from a mobile phone, the base station then transmits the signals to a 'switching centre' - a telephone exchange for mobile phones.
Base stations are in 'cells' A mobile phone system requires a number of base stations.
Each base station sits in the middle of a geographical area known as a 'cell'. In order to operate the mobile phone network as efficiently as possible, base stations are located so as to maximise the number of calls that can be connected during peak use periods. Therefore, the geographic size of a cell depends on the traffic during these periods. Cells in populated areas, with many mobile phone users, will be smaller than cells in less populated areas. As you cross the boundary of one cell, the cell next to it will automatically take over.