Patent ID: 8750234

Claim:
A mobile station apparatus which communicates with a base station apparatus using a plurality of component carriers and transmits Hybrid Automatic Repeat Request (HARQ) control information for a physical downlink shared channel transmission indicated by a detection of a corresponding physical downlink control channel, the mobile station apparatus comprising: a decoding unit configured to attempt to decode at least one physical downlink control channel on at least a first downlink component carrier; and a transmitting unit configured to transmit, to the base station apparatus, the HARQ control information using a first physical uplink control channel resource, the first physical uplink control channel resource being used for the transmission of the HARQ control information for the physical downlink shared channel transmission on a second downlink component carrier other than the first downlink component carrier, the physical downlink shared channel transmission on the second downlink component carrier being indicated by the detection of the corresponding physical downlink control channel, wherein the transmitting unit is configured to transmit, to the base station apparatus, the HARQ control information using a second physical uplink control channel resource, the second physical uplink control channel resource being used for the transmission of the HARQ control information for the physical downlink shared channel transmission only on the first downlink component carrier, the physical downlink shared channel transmission only on the first downlink component carrier being indicated by the detection of the corresponding physical downlink control channel.