A method for transmitting ACK/NACK (Acknowledge/Negative ACK) information at a user equipment in a wireless communication system, and a user equipment therefore are discussed. The method according to one embodiment includes generating an ACK/NACK payload for a plurality of carriers, the ACK/NACK payload including a plurality of concatenated ACK/NACK sets. Each ACK/NACK set is associated with a respective one of the plurality of carriers and has one or more ACK/NACK bits. The method further includes transmitting the ACK/NACK payload through a PUCCH (Physical Uplink Control Channel) or PUSCH (Physical Uplink Shared Channel). The ACK/NACK payload includes an ACK/NACK bit for a semi-persistent scheduled downlink signal. The ACK/NACK bit for the semi-persistent scheduled downlink signal is positioned at an end of a corresponding ACK/NACK set, not an end of the ACK/NACK payload.