Method for transmitting or receiving ACK/NACK signal in wireless communication system and apparatus for same

A user equipment (UE) for receiving an acknowledgement (ACK)/non-acknowledgement (NACK) signal in a wireless communication system, the UE comprising:

• a transmitter to transmit an uplink signal including a UE identifier of the UE on a resource belonging to a first resource pool based on a contention-based multiple access scheme;
• and
• a processor to attempt to detect an ACK signal and a NACK signal for the uplink signal from a second resource pool related to the first resource pool,
• wherein in attempting to detect the ACK signal and the NACK signal, the processor assumes that the ACK signal is UE-specifically signaled based on the UE identifier, and the NACK signal is broadcasted through a bitmap,
• wherein the bitmap includes a plurality of bits, each of the plurality of bits being related to each of a plurality of resources belonging to the first resource pool, and
• wherein the UE determines a failure cause in transmission of the uplink signal based on a bit value related to the resource for transmission of the uplink signal.

A method of transmitting an acknowledgement (ACK)/non-acknowledgement (NACK) signal by a base station in a wireless communication system, the method comprising:

• attempting to detect an uplink signal including a user equipment (UE) identifier on a resource belonging to a first resource pool,
• wherein the uplink signal is transmitted based on a contention-based multiple access scheme;
• and
• transmitting an ACK signal and a NACK signal for the uplink signal on a second resource pool related to the first resource pool,
• wherein in transmitting the ACK signal and the NACK signal, the base station UE-specifically signals the ACK signal based on the UE identifier, and broadcasts the NACK signal through a bitmap,
• wherein the bitmap includes a plurality of bits, each of the plurality of bits being related to each of a plurality of resources belonging to the first resource pool, and
• wherein the UE determines a failure cause in transmission of the uplink signal based on a bit value related to the resource for transmission of the uplink signal.

A base station for transmitting an acknowledgement (ACK)/non-acknowledgement (NACK) signal in a wireless communication system, the base station comprising:

• a processor to attempt to detect an uplink signal including a user equipment (UE) identifier on a resource belonging to a first resource pool,
• wherein the uplink signal is transmitted based on a contention-based multiple access scheme;
• and
• a transmitter to transmit an ACK signal and a NACK signal for the uplink signal from a second resource pool related to the first resource pool under control of the processor,
• wherein in transmitting the ACK signal and the NACK signal, the processor UE-specifically signals the ACK signal based on the UE identifier, and broadcasts the NACK signal through a bitmap,
• wherein the bitmap includes a plurality of bits, each of the plurality of bits being related to each of a plurality of resources belonging to the first resource pool, and
• wherein the UE determines a failure cause in transmission of the uplink signal based on a bit value related to the resource for transmission of the uplink signal.