Method for transmitting or receiving ACK/NACK signal in wireless communication system and apparatus for same
A method for a terminal receiving an ACK/NACK signal in a wireless communication system, according to one embodiment of the present invention, comprise the steps of: transmitting an uplink signal including a terminal identifier of the terminal through one of a plurality of resources belonging to a first resource pool, according to a contention-based multiple access scheme; and attempting detection of an ACK signal and/or a NACK signal relating to the uplink signal from a second resource pool linked to the first resource pool, wherein when the terminal attempts detection of the ACK signal or the NACK signal, the ACK signal is assumed to be terminal-specifically signaled based on the terminal identifier, and the NACK signal is assumed to be broadcasted through a bitmap specific to the first resource pool.
1. A method of receiving an acknowledgement (ACK)/non-acknowledgement (NACK) signal by a user equipment (UE) in a wireless communication system, the method comprising:
transmitting 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
attempting 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 UE 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.
2. The method of claim 1 , wherein, based on the bit value being a first value, the UE regards that initial transmission of the uplink signal has been failed due to a lack of a transmission power, and retransmits the uplink signal by boosting the transmission power.
3. The method of claim 1 , wherein, based on the bit value being a second value, the UE regards that initial transmission of the uplink signal has been failed due to interference from another UE, and retransmits the uplink signal at a coding rate lower than that of the initial transmission or retransmits the uplink signal through a third resource pool having a unit resource greater than that of the first resource pool.
4. The method of claim 1 ,
wherein the UE disregards the NACK signal based on the ACK signal being detected, even though the NACK signal is detected if the ACK signal is detected, and
wherein the UE performs uplink retransmission based on the ACK signal being not detected and the NACK signal being detected.
5. The method of claim 1 , further comprising:
receiving, from a base station, information regarding each of the first resource pool for initial transmission of the uplink signal and the third resource pool for retransmission of the uplink signal.
6. 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.
7. 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.
8. The method of claim 7 , wherein, based on detection of the uplink signal being failed due to a lack of a transmission power, the base station sets the bit value to a first value, and based on detection of the uplink signal being failed due to interference from another UE, the base station sets the bit value to a second value.
9. The method of claim 7 , further comprising:
receiving the uplink signal retransmitted from the UE after the NACK signal is transmitted,
wherein the retransmitted uplink signal has a coding rate lower than that of initial transmission or is received through a third resource pool having a unit resource greater than that of the first resource pool.
10. The method of claim 9 , further comprising:
transmitting information regarding each of the first resource pool for initial transmission of the uplink signal and the third resource pool for retransmission of the uplink signal.
11. 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.