To review communication conditions as needed.

A demodulator (52) of a mobile terminal (12-1) measures the signal quality of a received downlink signal, and supplies the measured signal quality to an environmental change detector (54). The environmental change detector (54) detects whether the prescribed change occurs that involves reviewing communication conditions, on the basis of the comparison result of different statistics for different time periods of the signal quality from the demodulator (52). The mobile terminal (12-1) transmits the results of environmental change detection by the environmental change detector (54) to a base station (10A) over the uplink. A controller (20) of the base station (10A) notifies a management server (14) of the results of environmental change detection from the mobile terminal (12-1). The management server (14) reviews communication conditions for base stations (10A, 10B), such as base station parameters, according to the results of environmental change detection from the base stations (10A, 10B).