Abstract: The handover method disclosed relates to a mobile communication system in which, based on the number of handovers in mobile units, the size of the radio zone to be assigned to a mobile unit is selected. The mobile switching center measures the number of handovers in each of the mobile units engaging in communication and, during the handover in the mobile unit, the handover target radio zone is assigned based on the measured value of the number of handovers. The target handover of mobile units is determined by the target determination controller based the number of handovers memorized in the handover number recorder. The assignment of the appropriate size radio zone prevents an excess load on the mobile switching center and the capacity to accommodate subscribers in the mobile communication system is enhanced.

Abstract: In a TDMA cellular mobile communication system, incoming signals from the public switched network are converted by speech coder/data compressor units of a MTSO (mobile telephone switching office) to low-bit-rate signals and combined into a first TDM signal for transmission to a base station. The components of the first TDM signal are respectively routed according to a channel assignment signal and fed into desired modulators which are periodically activated according to the channel assignment signal to transmit signals on assigned channels to mobile units. Signals from the mobile units are received by demodulators at the base station and combined into a second TDM signal which is transmitted to the MTSO. The components of the second TDM signal are routed according to the channel assignment signal to appropriate speech decoder/data expander units for conversion to the original high-bit-rate signals for transmission to the network.

Abstract: In a cellular mobile communication system, each base station is allocated common frequencies shared with other base stations in addition to unique frequencies. One of the unique frequencies is assigned by a base station to a mobile terminal in response to a call request. The field strength of a signal from that mobile terminal is detected and one of the common frequencies is assigned to it if the detected field strength becomes lower than a threshold. The base station receives a field strength signal from a neighboring station indicating the field strength of a version of the signal at the neighboring station and compares it with a threshold, and combines the signal of that mobile terminal with the version of the signal received by and relayed from the neighboring station when the field strength of that version of the signal is higher than the threshold. At the given mobile station, a signal from the base station which assigned the common frequency is combined with a signal from the neighboring station.

Abstract: A mobile communication system in which overlapping location areas are defined by radio base stations on an autonomous distribution basis. In a first embodiment, a mobile station registers the location thereof when moved in a radio zone which is not included in a location area notified by a radio base station and held therein. In a second embodiment, the mobile station registers the location when entered a radio zone in which location area being notified by the radio base station does not include the radio zone where the mobile station registered the location last. In a first and a second embodiment, the mobile station memorizes radio zones which it has passed after location registration as route information and may report the route information to a radio base station in the event of next location registration. The radio base station sequentially includes in the location area the radio zones which frequently appear in the route information.