| 摘要 |
PURPOSE:To realize hand off during conversation without providing the receivers of two systems, and besides, without making a signal burst-like. CONSTITUTION:The radio frequencies of a number corresponding to zone traffic of radio zones are allocated to the radio zones 2a to 2d, and one frequency f1 among these frequencies is allocated in common to all the zones, and as for the same frequency, spreading codes different for every zone are allocated. A mobile machine is provided with two correlators 15, 16 in, e.g. the zone 2a to communicate by the frequency f2, and when speech quality is deteriorated, the mobile machine executes once switching to the common frequency f1, and continues communication by one side of the correlators 15, 16, and simultaneously, scans spreading codes by the other side, and measures the receiving level of a down signal, and determines a hand off destination radio zone. When the determined zone is 2a, for instance, the communication is continued by switching the communication to the communication by the frequency f2 or f3 other than the common frequency f1. In the zone other than the zone 2d to which only f1 is allocated, the common frequency f1 is used only for the switching of channel during conversation and line setting, etc., at the time of the origination and the termination of a call. |
