Abstract: A wireless telephone system provides telecommunications services for personal wireless telephone sets over an area which is divided into service cells. Each of the cells is defined by reception characteristics of a plurality of radio base stations within the cell. The telephone system includes a service controller and a port being wireline connected between each radio base station and the service controller. The service controller selects radio base stations for setting up radio links with wireless sets of calling or called persons. A base station which serves a wireless set and surrounding idle base stations monitor strengths of radio signals received from the wireless set and report running averages of the monitored signal strengths to the service controller. Movement of the wireless set from one cell to another cell during a call is detected as a drop in the running average reported by the serving base station.