| 摘要 |
PURPOSE:To suppress the deterioration of a frequency use efficiency due to the double use of the radio line at the time of using an on-vehicle repeater by selecting a micro zone base station and a small zone base station, which can be directly communicated, without using the on-vehicle repeater. CONSTITUTION:Micro zone base stations a101 and b102 and small zone base stations c201 and d202 transmit the base station information of present transmitting electric powers Pa, Pb, Pc and Pd. A portable terminal 20 periodically receives the signal from base stations a101, b102, c201 and d202. From the base station transmitting electric power code in a signal, the transmitting electric powers Pa, Pb, Pc and Pd and actually received receiving electric powers Ea, Eb, Ec and Ed are obtained, From the difference between both, propagation losses La, Lb, Lc and Ld of respective base stations are obtained. When the call is executed by the outgoing call and the incoming call, the portable terminal 20 selects the base station with the smallest of the propagation losses La, Lb, Lc and Ld of respective base stations and sends an communication request signal. |
