June 25, 2008 2:06am CST
hi friends. cellphones communication system fast growing communication system in the world. we can convery our ideas through cellphones very fastly. cellular telephone" or cellular radio, telecommunication system in which a portable or mobile radio trasmitter and receiver, or "telephone", is linked via microwave radio frequnecies to base transmitter and receiver stations that connent the user to a convential tephone network. the geographic region served by a cellular system is subdivided into aareas called cells. Each cell has a central base station and two sets of assigned tramission frequencies, one set is used by the base station, and the other by mobile telephone communication . its prevent radio interference, each well uses frequencies different from those used by its surrounding cells, but cells sufficiently distant from each other can use the same frequencies. when a mobile telephone leaves one cell and enters another, the the telephone call is transferred from one base station and set of tramission frequencies to using a computerized switching system. the first cellular telephone system began operation in tokyo in 1979, and the first u.s system began operation in 1983 in chicago. now we are develop in camera phones ect. share your ideas with me. thank you. have a nice day.