Patent ID: 8837414

Claim:
A method for, at a user equipment (UE), transmitting Acknowledgement/Negative ACK (ACK/NACK) in a wireless communication system where carrier aggregation is configured, the method comprising: receiving one or more physical downlink control channels (PDCCHs); receiving one or more physical downlink shared channels (PDSCHs) corresponding to the one or more PDCCHs; and transmitting an ACK/NACK signal for the one or more PDSCHs via a physical uplink control channel (PUCCH), wherein the ACK/NACK signal is transmitted using a first PUCCH format if the number of the PDCCHs is 1 and both the PDCCH and the PDSCH corresponding to the PDCCH are received through a primary carrier, wherein the ACK/NACK signal is transmitted using a second PUCCH format if a number of PDCCHs is 2 or greater.