A base station apparatus for communicating to a mobile station over a downlink shared channel includes a reception unit configured to receive downlink radio quality information from the mobile station over a control channel frequency-multiplexed with an uplink shared channel, a measurement unit configured to measure a radio quality of the control channel, and a determination unit configured to determine reliability of the downlink radio quality information based on the radio quality. Also, a communication control method at a base station apparatus for communicating to a mobile station over a downlink shared channel includes receiving downlink radio quality information from the mobile station over a control channel frequency-multiplexed with an uplink shared channel, measuring a radio quality of the control channel, and determining based on the radio quality whether the mobile station has transmitted the downlink radio quality information.