A base station apparatus comprising: a reception unit configured to receive, on a physical uplink shared channel from a mobile station apparatus, one or more signal pre-coding information reported using a periodic feedback mode or an aperiodic feedback mode, the periodic feedback mode being such that all wideband reception quality information and transmit signal pre-coding information, as well as one reception quality information and transmit signal pre-coding information which are to be applied to a plurality of sub-bands selected by the mobile station apparatus, are simultaneously transmitted in one sub-frame, the aperiodic feedback mode being such that respective reception quality information and transmit signal pre-coding information corresponding to all sub-bands are simultaneously transmitted in one sub-frame, and each transmit signal pre-coding information indicating a pre-coding to be performed on a downlink signal to be transmitted to the mobile station apparatus; and a transmission unit configured to transmit to the mobile station apparatus in response to receiving the one or more transmit signal pre-coding information, the downlink signal on a physical downlink control channel, wherein for a case that first transmit signal pre-coding information most recently received among the one or more transmit signal pre-coding information has been reported using the aperiodic feedback mode, the downlink signal includes a pre-coder confirmation indicating that the first transmit signal pre-coding information has been used to pre-code the downlink signal, and for a case that the first transmit signal pre-coding information has been reported using the periodic feedback mode, the downlink signal includes, instead of the pre-coder confirmation, one of the one or more transmit signal pre-coding information which has been used to pre-code the downlink signal. a reception unit configured to receive, on a physical uplink shared channel from a mobile station apparatus, one or more signal pre-coding information reported using a periodic feedback mode or an aperiodic feedback mode, the periodic feedback mode being such that all wideband reception quality information and transmit signal pre-coding information, as well as one reception quality information and transmit signal pre-coding information which are to be applied to a plurality of sub-bands selected by the mobile station apparatus, are simultaneously transmitted in one sub-frame, the aperiodic feedback mode being such that respective reception quality information and transmit signal pre-coding information corresponding to all sub-bands are simultaneously transmitted in one sub-frame, and each transmit signal pre-coding information indicating a pre-coding to be performed on a downlink signal to be transmitted to the mobile station apparatus; and a transmission unit configured to transmit to the mobile station apparatus in response to receiving the one or more transmit signal pre-coding information, the downlink signal on a physical downlink control channel, wherein for a case that first transmit signal pre-coding information most recently received among the one or more transmit signal pre-coding information has been reported using the aperiodic feedback mode, the downlink signal includes a pre-coder confirmation indicating that the first transmit signal pre-coding information has been used to pre-code the downlink signal, and for a case that the first transmit signal pre-coding information has been reported using the periodic feedback mode, the downlink signal includes, instead of the pre-coder confirmation, one of the one or more transmit signal pre-coding information which has been used to pre-code the downlink signal. <EOS>