Method and device for determining feedback resource in NR V2X
A method for performing wireless communication by a first device and a device for supporting same are provided. The method may comprise the steps of: receiving a physical sidelink shared channel (PSSCH) from a second device; determining a physical sidelink feedback channel (PSFCH) resource associated with the PSSCH; and transmitting hybrid automatic repeat request (HARQ) feedback to the second device on the PSFCH resource. Here, the PSFCH resource can be determined on the basis of a sub channel associated with the PSSCH, a slot associated with the PSSCH, a cast type of communication between the first device and the second device, an ID of the first device, and a source ID of the second device.
1. A method for performing, by a first device, wireless communication, the method comprising:
receiving, from a second device, a physical sidelink shared channel (PSSCH);
determining a physical sidelink feedback channel (PSFCH) resource related to the PSSCH, based on (i) an ID of the first device and (ii) a source ID of the second device; and
transmitting, to the second device, a hybrid automatic repeat request (HARQ) feedback based on the PSFCH resource,
wherein the PSFCH resource is determined among at least one PSFCH resource determined based on (i) a sub-channel related to the PSSCH and (ii) a slot related to the PSSCH,
wherein the ID of the first device is determined based on a cast type of sidelink communication between the first device and the second device, and
wherein the ID of the first device is determined to be zero, based on the cast type being unicast.
2. The method of claim 1 , wherein the ID of the first device is determined to be a non-zero value, based on the cast type being groupcast in which ACK transmission or NACK transmission is allowed.
3. The method of claim 2 , wherein, in the groupcast in which ACK transmission or NACK transmission is allowed, the HARQ feedback is ACK based on successful decoding of data on the PSSCH by the first device, and the HARQ feedback is NACK based on failure of decoding of data on the PSSCH by the first device.
4. The method of claim 2 , wherein the ID of the first device is an ID allocated by a higher layer.
5. The method of claim 1 , wherein the ID of the first device is determined to be zero, based on the cast type being groupcast in which only NACK transmission is allowed.
6. The method of claim 5 , wherein, in the groupcast in which only NACK transmission is allowed, the HARQ feedback is NACK based on failure of decoding of data on the PSSCH by the first device, and the HARQ feedback is not transmitted based on successful decoding of data on the PSSCH by the first device.
7. The method of claim 1 , further comprising:
determining information related to a cyclic shift applied to the HARQ feedback on the PSFCH resource.
8. The method of claim 7 , wherein the information related to the cyclic shift applied to the HARQ feedback on the PSFCH resource is determined based on the ID of the first device.
9. The method of claim 7 , wherein the HARQ feedback is transmitted to the second device on the PSFCH resource based on the information related to the cyclic shift.
10. The method of claim 1 , wherein the source ID of the second device is included in a sidelink control information (SCI) received through the PSSCH.
11. A first device configured to perform wireless communication, the first device comprising:
one or more transceivers;
one or more processors; and
one or more memories operably connected to the one or more processors and storing instructions that, when executed by the one or more processors, perform operations comprising:
receiving, from a second device through the one or more transceivers, a physical sidelink shared channel (PSSCH);
determining a physical sidelink feedback channel (PSFCH) resource related to the PSSCH, based on (i) an ID of the first device and iii) a source ID of the second device; and
transmitting, to the second device through the one or more transceivers, a hybrid automatic repeat request (HARQ) feedback based on the PSFCH resource,
wherein the PSFCH resource is determined among at least one PSFCH resource determined based on (i) a sub-channel related to the PSSCH and (ii) a slot related to the PSSCH,
wherein the ID of the first device is determined based on a cast type of sidelink communication between the first device and the second device, and
wherein the ID of the first device is determined to be zero, based on the cast type being unicast.
12. The first device of claim 11 , wherein the ID of the first device is determined to be a non-zero value, based on the cast type being groupcast in which ACK transmission or NACK transmission is allowed.
13. The first device of claim 12 , wherein, in the groupcast in which ACK transmission or NACK transmission is allowed, the HARQ feedback is ACK based on successful decoding of data on the PSSCH by the first device, and the HARQ feedback is NACK based on failure of decoding of data on the PSSCH by the first device.
14. The first device of claim 12 , wherein the ID of the first device is an ID allocated by a higher layer.
15. The first device of claim 11 , wherein the ID of the first device is determined to be zero, based on the cast type being groupcast in which only NACK transmission is allowed.
16. The first device of claim 15 , wherein, in the groupcast in which only NACK transmission is allowed, the HARQ feedback is NACK based on failure of decoding of data on the PSSCH by the first device, and the HARQ feedback is not transmitted based on successful decoding of data on the PSSCH by the first device.
17. An apparatus configured to control a first user equipment (UE) performing wireless communication, the apparatus comprising:
one or more processors; and
one or more memories operably connected to the one or more processors and storing instructions that, when executed by the one or more processors, perform operations comprising:
receiving, from a second UE, a physical sidelink shared channel (PSSCH);
determining a physical sidelink feedback channel (PSFCH) resource related to the PSSCH, based on (i) an ID of the first UE and iii) a source ID of the second UE; and
transmitting, to the second UE, a hybrid automatic repeat request (HARQ) feedback based on the PSFCH resource,
wherein the PSFCH resource is determined among at least one PSFCH resource determined based on (i) a sub-channel related to the PSSCH and (ii) a slot related to the PSSCH,
wherein the ID of the first UE is determined based on a cast type of sidelink communication between the first UE and the second UE, and
wherein the ID of the first UE is determined to be zero, based on the cast type being unicast.
18. The apparatus of claim 17 , wherein the ID of the first UE is determined to be zero, based on the cast type being groupcast in which only NACK transmission is allowed.