A user equipment, UE, comprising: a receiving circuitry that is adapted to: receive, from a base station apparatus, a higher layer signal including first information used for indicating a specific downlink component carrier, receive, from the base station apparatus, the higher layer signal including second information used for indicating a first physical uplink control channel resource, and receive, from the base station apparatus, the higher layer signal including third information used for indicating a second physical uplink control channel resource; and a transmitting circuitry adapted to transmit, to the base station apparatus, Hybrid Automatic Repeat Request, HARQ, control information, characterized in that the transmitting circuitry is adapted to transmit in a subframe, to the base station apparatus, the HARQ control information using the first physical uplink control channel resource and a first physical uplink control channel format, the first physical uplink control channel resource and the first physical uplink control channel format being used for the transmission of the HARQ control information for a physical downlink shared channel transmission on a downlink component carrier different from the specific downlink component carrier, the physical downlink shared channel transmission being indicated by a detection of a physical downlink control channel in a UE-specific search space, and the transmitting circuitry is adapted to transmit in a subframe, to the base station apparatus, the HARQ control information using the second physical uplink control channel resource and a second physical uplink control channel format, the second physical uplink control channel resource and the second physical uplink control channel format being used for the transmission of the HARQ control information for a physical downlink shared channel transmission only on the specific downlink component carrier, the physical downlink shared channel transmission being indicated by a detection of a physical downlink control channel in a common search space, the first physical uplink control channel format is used for transmitting the HARQ control information together with a scheduling request. receive, from a base station apparatus, a higher layer signal including first information used for indicating a specific downlink component carrier, receive, from the base station apparatus, the higher layer signal including second information used for indicating a first physical uplink control channel resource, and receive, from the base station apparatus, the higher layer signal including third information used for indicating a second physical uplink control channel resource; and a transmitting circuitry adapted to transmit, to the base station apparatus, Hybrid Automatic Repeat Request, HARQ, control information, characterized in that the transmitting circuitry is adapted to transmit in a subframe, to the base station apparatus, the HARQ control information using the first physical uplink control channel resource and a first physical uplink control channel format, the first physical uplink control channel resource and the first physical uplink control channel format being used for the transmission of the HARQ control information for a physical downlink shared channel transmission on a downlink component carrier different from the specific downlink component carrier, the physical downlink shared channel transmission being indicated by a detection of a physical downlink control channel in a UE-specific search space, and the transmitting circuitry is adapted to transmit in a subframe, to the base station apparatus, the HARQ control information using the second physical uplink control channel resource and a second physical uplink control channel format, the second physical uplink control channel resource and the second physical uplink control channel format being used for the transmission of the HARQ control information for a physical downlink shared channel transmission only on the specific downlink component carrier, the physical downlink shared channel transmission being indicated by a detection of a physical downlink control channel in a common search space, the first physical uplink control channel format is used for transmitting the HARQ control information together with a scheduling request.