Showing papers in "Electronics in 1979"

Cellular system expands number of mobile-phone channels

Abstract: Anyone trying to make even a local call from a phone in an automobile soon discovers that it is very difficult to get a clear channel. Advanced Mobile Phone Service which uses decentralized, low-power transmitters and antennas to link calls made to or from cars to the regular phone lines. The same frequencies may be used by different transmitters, provided they are at a sufficient distance from one another. Through frequency reuse, a cellular mobile-telephone system in one coverage area can handle many more calls simultaneously than the number of allocated frequency channels. A hexagonal cell is the most efficient, requiring the fewest transmitter sites. LSI and stored-program control make the system practical.