Patent ID: 8767651

Claim:
A mobile communication system comprising: a base station apparatus; and a mobile station apparatus, wherein the base station apparatus and the mobile station apparatus are configured to communicate using a plurality of component carriers, the base station apparatus is configured to: transmit in a subframe on a specific downlink component carrier, to the mobile station apparatus, a first physical downlink control channel for indicating a first physical downlink shared channel transmission and a second physical downlink control channel for indicating a second physical downlink shared channel transmission, the mobile station apparatus is configured to: determine a first physical uplink control channel resource based on a control channel element of the first physical downlink control channel and a second physical uplink control channel resource based on a control channel element of the second physical downlink control channel in a case that the first physical downlink control channel and the second physical downlink control channel are received in a subframe on the specific component carrier, and transmit, to the base station apparatus, control information on hybrid automatic repeat request (HARQ) using a single physical uplink control channel resource which is selected, by the mobile station apparatus, among the first physical uplink control channel resource and the second physical uplink control channel resource, wherein the first physical uplink control channel resource and the second physical uplink control channel resource are mapped on a single uplink component carrier that corresponds to the specific downlink component carrier, and the control information on HARQ includes information that indicates ACK/NACK for each of downlink transport blocks transmitted on the first physical downlink shared channel and the second physical downlink shared channel.