Method and device for reporting SL HARQ feedback to base station in NR V2X
A method for performing wireless communication by a first device and a device supporting same may be provided. The method may comprise the steps of: receiving, from a base station, information related to an uplink (UL) resource for reporting sidelink (SL) hybrid automatic repeat request (HARQ) feedback to the base station; transmitting first sidelink control information (SCI) to a second device through a physical sidelink control channel (PSCCH); transmitting second SCI and a medium access control protocol data unit (MAC PDU) to the second device through a physical sidelink shared channel (PSSCH) related to the PSCCH; determining a physical sidelink feedback channel (PSFCH) resource on the basis of an index of a sub channel and an index of a slot related to the PSSCH; and transmitting the SL HARQ feedback on the MAC PDU to the base station on the basis of the UL resource. A minimum time gap between the PSFCH resource and the UL resource may be determined on the basis of N, X, numerology of an SL bandwidth part (BWP), and numerology of a UL BWP, wherein N may be determined on the basis of a minimum value among the numerology of the SL BWP and the numerology of the UL BWP, and X may be determined on the basis of information related to a priority.
1. A method for performing wireless communication by a first device, the method comprising:
receiving, from a base station, information related to an uplink (UL) resource for reporting sidelink (SL) hybrid automatic repeat request (HARQ) feedback to the base station;
transmitting, to a second device, first sidelink control information (SCI) through a physical sidelink control channel (PSCCH);
transmitting, to the second device, second SCI and a medium access control (MAC) protocol data unit (PDU) through a physical sidelink shared channel (PSSCH) related to the PSCCH;
determining a physical sidelink feedback channel (PSFCH) resource based on an index of a subchannel and an index of a slot related to the PSSCH; and
transmitting, to the base station, the SL HARQ feedback for the MAC PDU based on the UL resource,
wherein a minimum time gap between the PSFCH resource and the UL resource is determined based on N, X, a numerology of a SL bandwidth part (BWP), and a numerology of a UL BWP,
wherein N is determined based on a minimum value among the numerology of the SL BWP and the numerology of the UL BWP, and
wherein X is determined based on information related to a priority.
2. The method of claim 1 , wherein the priority is a highest priority among at least one priority allowed for a SL grant allocated by the base station for transmission of the MAC PDU.
3. The method of claim 1 , wherein X determined based on a low priority is greater than X determined based on a high priority.
4. The method of claim 1 , wherein X is determined based on a latency requirement, and
wherein X determined based on a long latency requirement is greater than X determined based on a short latency requirement.
5. The method of claim 1 , wherein X is determined based on a HARQ feedback option related to the MAC PDU,
wherein the HARQ feedback option is a NACK-only feedback option or an ACK/NACK feedback option, and
wherein X determined based on the ACK/NACK feedback option is greater than X determined based on the NACK-only feedback option.
6. The method of claim 1 , wherein X is determined based on a PSFCH resource period, and
wherein X determined based on a long PSFCH resource period is greater than X determined based on a short PSFCH resource period.
7. The method of claim 1 , further comprising:
reporting, to the base station, information related to simultaneous processing capability for a PSFCH of the first device,
wherein X is determined based on the simultaneous processing capability for the PSFCH of the first device, and
wherein X determined based on low simultaneous processing capability for the PSFCH is greater than X determined based on high simultaneous processing capability for the PSFCH.
8. The method of claim 1 , wherein X is determined based on a difference between a first synchronization related to Uu communication between the base station and the first device and a second synchronization related to SL communication between the first device and the second device, and
wherein X determined based on a large difference is greater than X determined based on a small difference.
9. The method of claim 1 , further comprising:
measuring a channel busy ratio (CBR) for a resource pool; and
reporting, to the base station, information on the CBR,
wherein X is determined based on the CBR, and
wherein X determined based on a large CBR is less than X determined based on a small CBR.
10. The method of claim 1 , wherein X is determined based on a cast type of the first device,
wherein the cast type includes groupcast or unicast, and
wherein X determined based on the groupcast is less than X determined based on the unicast.
11. The method of claim 1 , wherein the minimum time gap is less than or equal to a time gap between the UL resource and the PSFCH resource.
12. The method of claim 1 , wherein the UL resource is related to at least one PSFCH resource,
wherein the PSFCH resource is a last PSFCH resource among the at least one PSFCH resource, and
wherein, based on the minimum time gap being greater than a time gap between the UL resource and the PSFCH resource, SL HARQ feedback related to the last PSFCH resource is not included in the SL HARQ feedback transmitted to the base station.
13. The method of claim 1 , wherein, based on a plurality of PSFCHs having a same reception power detected on the PSFCH resource, it is determined that the SL HARQ feedback is NACK.
14. A first device adapted to perform wireless communication, the first device comprising:
one or more memories storing instructions;
one or more transceivers; and
one or more processors connected to the one or more memories and the one or more transceivers, wherein the one or more processors execute the instructions to:
receive, from a base station, information related to an uplink (UL) resource for reporting sidelink (SL) hybrid automatic repeat request (HARQ) feedback to the base station;
transmit, to a second device, first sidelink control information (SCI) through a physical sidelink control channel (PSCCH);
transmit, to the second device, second SCI and a medium access control (MAC) protocol data unit (PDU) through a physical sidelink shared channel (PSSCH) related to the PSCCH;
determine a physical sidelink feedback channel (PSFCH) resource based on an index of a subchannel and an index of a slot related to the PSSCH; and
transmit, to the base station, the SL HARQ feedback for the MAC PDU based on the UL resource,
wherein a minimum time gap between the PSFCH resource and the UL resource is determined based on N, X, a numerology of a SL bandwidth part (BWP), and a numerology of a UL BWP,
wherein N is determined based on a minimum value among the numerology of the SL BWP and the numerology of the UL BWP, and
wherein X is determined based on information related to a priority.
15. The first device of claim 14 , wherein the priority is a highest priority among at least one priority allowed for a SL grant allocated by the base station for transmission of the MAC PDU.
16. The first device of claim 14 , wherein X determined based on a low priority is greater than X determined based on a high priority.
17. The first device of claim 14 , wherein X is determined based on a latency requirement, and
wherein X determined based on a long latency requirement is greater than X determined based on a short latency requirement.
18. The first device of claim 14 , wherein X is determined based on a HARQ feedback option related to the MAC PDU,
wherein the HARQ feedback option is a NACK-only feedback option or an ACK/NACK feedback option, and
wherein X determined based on the ACK/NACK feedback option is greater than X determined based on the NACK-only feedback option.
19. The first device of claim 14 , wherein X is determined based on a PSFCH resource period, and
wherein X determined based on a long PSFCH resource period is greater than X determined based on a short PSFCH resource period.
20. A processing device adapted to control a first device, the processing device comprising:
one or more processors; and
one or more memories operably connected to the one or more processors and storing instructions, wherein the one or more processors execute the instructions to:
receive, from a base station, information related to an uplink (UL) resource for reporting sidelink (SL) hybrid automatic repeat request (HARQ) feedback to the base station;
transmit, to a second device, first sidelink control information (SCI) through a physical sidelink control channel (PSCCH);
transmit, to the second device, second SCI and a medium access control (MAC) protocol data unit (PDU) through a physical sidelink shared channel (PSSCH) related to the PSCCH;
determine a physical sidelink feedback channel (PSFCH) resource based on an index of a subchannel and an index of a slot related to the PSSCH; and
transmit, to the base station, the SL HARQ feedback for the MAC PDU based on the UL resource,
wherein a minimum time gap between the PSFCH resource and the UL resource is determined based on N, X, a numerology of a SL bandwidth part (BWP), and a numerology of a UL BWP,
wherein N is determined based on a minimum value among the numerology of the SL BWP and the numerology of the UL BWP, and
wherein X is determined based on information related to a priority.