System design for portable telephones: methods to enable initiating and receiving calls from a vehicle

The author proposes the application of the small zone format which adapts the microcell for plural position-registration as one step in realizing a portable telephone set method for communicating at any time, at any place, and to anywhere by using cordless telephones with small (10 mW) output power. Another proposal is to install cordless-telephone key service units on poles along the streets in spans of 100 to 200 meters for transmissions between portable telephone sets: by overlapping the service zones with at least two adjacent cordless telephone key service units, plural-position registration would be implemented. It is also proposed that a transmission diversity technique be used to eliminate the instantaneous disconnections of the speech paths that would be caused by channel switching while frequently crossing through the microcell zones