Method of transmitting ACK/NACK message in wireless communication system and terminal using same method
The present invention relates to a Vehicle-to-X (V2X) operation method performed by a V2X terminal in a wireless communication system. Provided is the method comprising: receiving, from a base station, unicast data and multicast data, and transmitting, to the base station, an acknowledgment (ACK)/negative acknowledgement (NACK) for the unicast data and ACK/NACK for the multicast data, wherein the unicast data is data for the V2X terminal and the multicast data is data for a plurality of V2X terminals comprising the V2X terminal.
1. A method for performing vehicle-to-X (V2X) operation in a wireless communication system, the method performed by a V2X terminal comprising:
receiving, from a base station, unicast data and multicast data; and
transmitting, to the base station, an acknowledgement (ACK)/negative acknowledgement (NACK) for the unicast data and ACK/NACK for the multicast data,
wherein the unicast data is data for the V2X terminal and the multicast data is data for a plurality of V2X terminals including the V2X terminal, and
wherein the V2X terminal transmits ACK/NACK for the unicast data and ACK/NACK for the multicast data according to a payload size determined based on whether only the unicast data is received or whether the unicast data and the multicast data are simultaneously received.
2. The method of claim 1 , wherein
the V2X terminal transmits ACK/NACK for the unicast data and ACK/NACK for the multicast data according to a payload size determined based on whether the V2X terminal receives scheduling information regarding the multicast data.
3. The method of claim 1 , wherein
the V2X terminal transmits ACK/NACK for the unicast data and ACK/NACK for the multicast data based on reliability required for the unicast data and the multicast data.
4. The method of claim 3 , wherein
based on the V2X terminal transmitting ACK/NACK for the unicast data and ACK/NACK for the multicast data, the V2X terminal differently applies the number of resource elements used in uplink control information (UCI) piggyback of ACK/NACK for data required to have relatively high reliability and the number of resource elements used in UCI piggyback of ACK/NACK for data required to have relatively low reliability.
5. The method of claim 4 , wherein
the number of resource elements used in UCI piggyback of ACK/NACK for the data required to have relatively high reliability is greater than the number of resource elements used in UCI piggyback of ACK/NACK for the data required to have relatively low reliability.
6. The method of claim 3 , wherein
based on the V2X terminal transmitting ACK/NACK for the unicast data and ACK/NACK for the multicast data, the V2X terminal differently applies transmission power of ACK/NACK transmission for the data required to have relatively high reliability and transmission power of ACK/NACK transmission for the data required to have relatively low reliability.
7. The method of claim 6 , wherein
the transmission power of ACK/NACK transmission for the data required to have relatively high reliability is higher than the transmission power of ACK/NACK transmission for the data required to have relatively low reliability.
8. The method of claim 1 , wherein
based on a transmission time of ACK/NACK for the unicast data and a transmission time of ACK/NACK for the multicast data overlap, ACK/NACK for the unicast data and ACK/NACK for the multicast data are transmitted based on priority.
9. The method of claim 8 wherein
the V2X terminal delays transmission of ACK/NACK for data having relatively low priority.
10. The method of claim 8 , wherein
the V2X terminal drops transmission of ACK/NACK for data having relatively low priority.
11. The method of claim 8 , wherein
the V2X terminal transmits ACK/NACK for the data having relatively low priority according to a type of a downlink subframe associated with an uplink subframe in which transmission of ACK/NACK for the data having relatively low priority is performed.
12. The method of claim 11 , wherein
the type of the downlink subframe is determined by at least one of a system information block (SIB) time division duplex (TDD) uplink downlink setting, a downlink hybrid automatic repeat and request (HARQ) reference setting, and a downlink HARQ time line.
13. The method of claim 8 , wherein
the V2X terminal transmits ACK/NACK for data having relatively low priority based on a downlink HARQ reference setting in a frequency division duplex (FDD) system.
14. A Vehicle-to-X (V2X) user equipment (UE) comprising:
a transceiver configured to transmit and receive a radio signal; and
a processor coupled to the transceiver and configured to:
receive, from a base station, unicast data and multicast data; and
transmit, to the base station, an acknowledgement (ACK)/negative acknowledgement (NACK) for the unicast data and ACK/NACK for the multicast data,
wherein the unicast data is data for the V2X UE and the multicast data is data for a plurality of V2X UEs including the V2X UE, and
wherein the V2X UE transmits ACK/NACK for the unicast data and ACK/NACK for the multicast data according to a payload size determined based on whether only the unicast data is received or whether the unicast data and the multicast data are simultaneously received.