A mobile station is configured to measure receiving qualities of respective signals from a first antenna and a second antenna of a base station (S3, S5), store the results of the measurement, and request the base station to retransmit a signal from an antenna with a higher receiving quality, based on the stored measurement results, when an error is detected in received data thereafter (S10, S11, S12). The base station retransmits the data, using the antenna with the higher receiving quality (i.e., a base station antenna to yield the higher receiving quality at the mobile station) (S15). In another aspect, the mobile station measures a receiving quality of a signal and notifies the base station of the receiving quality. The base station selects a radio channel adapted to a receiving quality on the basis of the measurement result and transmits a signal, using the radio channel.