A repeater apparatus for detecting a downlink HARQ ACK/NACK feedback signal from a base station is provided. An RF (Radio Frequency) unit receives specific channel configuration information which includes offset information indicating the starting point of a specific channel to which said HARQ ACK/NACK feedback signal is transmitted from the base station and the position of the specific channel allocated for an exclusive use of the repeater apparatus within the specific channel from said start point, and receives the HARQ ACK/NACK feedback signal from the base station for an uplink transmission of the repeater. The processor detects the specific channel allocated for exclusive use of the repeater apparatus based on the received specific channel configuration information thereby decoding the received HARQ ACK/NACK feedback signal.