High capacity automobile telephone system

The features of the 800MHz High Capacity Automobile Telephone System for public mobile services are described. The system has been developed and is now under construction in Tokyo metropolitan area. Major feature of this system are as follows. 1) High capacity: 100,000 subscribers can be accommodated in the same service area. 2) Efficient utilization of frequency spectrum in the 800MHz band : a) the introduction of small radio zone structure (cellular system) for reuse of the same frequency in radio zones with adequate distance apart by avoiding co-channel interference, b) the increase in the number of channels commonly used by each mobile unit within a radio zone, and, c) the reduction in the occupied bandwidth of radio channels. 3) Fully automatic exchange for a nationwide mobile service. 4)Introduction of various advanced techniques: a) Vehicle location registration technique, by which a switching equipment memorizes the newest location (paging area) of each mobile subscriber. b) Call hand off technique, which enables continuous conversation when a vehicle moves from one radio zone to another during a call. c) Multi-channel access control with two kinds of control channels (paging channel and access channel).