Technique to provide channel format and signal processing for efficiently transmitting control information

A User Equipment (UE) for transmitting Acknowledgement/Negative Acknowledgement (ACK/NACK) information in a wireless communication system, the UE comprising:

• a receiver configured to receive a downlink signal from a Base Station (BS);
• a transmitter configured to transmit an uplink signal to the BS;
• and
• a processor configured to control the UE including the receiver and the transmitter, wherein the processor is further configured to:
• configure the UE to use a Physical Uplink Control Channel (PUCCH) format 3 for the transmission of the ACK/NACK information;
• determine a PUCCH format between a PUCCH format 1a/1b and the PUCCH format 3 for transmission of the ACK/NACK information for downlink transmission in a downlink frame set including M downlink subframes is to be transmitted, wherein M≧1, in one uplink subframe, according to whether at least one of specific conditions is met;
• and
• transmit the ACK/NACK information using the determined PUCCH format in the one uplink subframe,
• wherein the ACK/NACK information is transmitted by using a PUCCH format 1a/1b, when at least one of the specific conditions is met,
• wherein one serving cell is configured for the UE, and
• wherein the specific conditions comprise:
• a first condition where one Physical Downlink Shared Channel (PDSCH) indicated by detection of a corresponding Physical Downlink Control Channel (PDCCH) with a Downlink Assignment Index (DAI) value of 1 is present in the downlink subframe set, and
• a second condition where one Semi-Persistent Scheduling (SPS) release PDCCH with the DAI value of 1 is present in the downlink subframe set.