Method and device for reselecting sidelink resources in NR V2X

1. A method for performing, by a first device, sidelink (SL) communication, the method comprising:

obtaining information related to a priority threshold value for pre-emption checking;

determining a first resource for SL transmission related to a first priority value;

receiving sidelink control information (SCI) including information related to a second resource and information related to a second priority value through a physical sidelink control channel (PSCCH);

obtaining a reference signal received power (RSRP) value based on a reference signal on a resource for the PSCCH or a reference signal on a resource for a physical sidelink shared channel (PSSCH) related to the PSCCH; and

performing resource reselection for the first resource, based on (i) the RSRP value which is greater than an RSRP threshold determined based on a combination of the first priority value and the second priority value, (ii) overlap of the first resource and the second resource, and (iii) the priority threshold value for pre-emption checking and a difference between the first priority value and the second priority value.

2. The method of claim 1 , wherein the first priority value is greater than the second priority value, and

wherein the difference between the first priority value and the second priority value exceeds a difference value between the first priority value and the second priority value determined by the priority threshold value.

3. The method of claim 1 , wherein, based on (i) the RSRP value which is greater than the RSRP threshold determined based on the combination of the first priority value and the second priority value, (ii) the overlap of the first resource and the second resource, and (iii) the first priority value which is less than or equal to the second priority value, the resource reselection for the first resource is not performed and the SL transmission is performed by the first device based on the first resource.

4. The method of claim 1 , wherein the second priority value is less than the priority threshold value.

5. The method of claim 4 , wherein the priority threshold value is configured for each resource pool.

6. The method of claim 1 , wherein performing the resource reselection for the first resource comprises removing the first resource and selecting a third resource.

7. The method of claim 6 , further comprising:

performing the SL transmission based on the third resource.

8. The method of claim 1 , wherein the first resource for the SL transmission related to the first priority value is determined by the first device based on sensing.

9. The method of claim 1 , wherein the reference signal on the resource for the PSCCH is a demodulation reference signal (DMRS) mapped to the resource for the PSCCH, and

wherein the reference signal on the resource for the PSSCH is a DMRS mapped to the resource for the PSSCH.

10. A first device adapted to perform sidelink (SL) communication, the first device comprising:

at least one memory storing instructions;

at least one transceiver; and

at least one processor connected to the at least one memory and the at least one transceiver, wherein the at least one processor executes the instructions to:

obtain information related to a priority threshold value for pre-emption checking;

determine a first resource for SL transmission related to a first priority value;

control the at least one transceiver to receive sidelink control information (SCI) including information related to a second resource and information related to a second priority value through a physical sidelink control channel (PSCCH);

obtain a reference signal received power (RSRP) value based on a reference signal on a resource for the PSCCH or a reference signal on a resource for a physical sidelink shared channel (PSSCH) related to the PSCCH; and

perform resource reselection for the first resource, based on (i) the RSRP value which is greater than an RSRP threshold determined based on a combination of the first priority value and the second priority value, (ii) overlap of the first resource and the second resource, and (iii) the priority threshold value for pre-emption checking and a difference between the first priority value and the second priority value.

11. The first device of claim 10 , wherein the first priority value is greater than the second priority value, and

wherein the difference between the first priority value and the second priority value exceeds a difference value between the first priority value and the second priority value determined by the priority threshold value.

12. The first device of claim 10 , wherein, based on (i) the RSRP value which is greater than the RSRP threshold determined based on the combination of the first priority value and the second priority value, (ii) the overlap of the first resource and the second resource, and (iii) the first priority value which is less than or equal to the second priority value, the resource reselection for the first resource is not performed and the SL transmission is performed by the first device based on the first resource.

13. An apparatus adapted to control a first user equipment (UE) performing sidelink (SL) communication, the apparatus comprising:

at least one processor; and

at least one memory connected to the at least one processor and storing instructions, wherein the at least one processor executes the instructions to:

obtain information related to a priority threshold value for pre-emption checking;

determine a first resource for SL transmission related to a first priority value;

receive sidelink control information (SCI) including information related to a second resource and information related to a second priority value through a physical sidelink control channel (PSCCH);

obtain a reference signal received power (RSRP) value based on a reference signal on a resource for the PSCCH or a reference signal on a resource for a physical sidelink shared channel (PSSCH) related to the PSCCH; and

perform resource reselection for the first resource, based on (i) the RSRP value which is greater than an RSRP threshold determined based on a combination of the first priority value and the second priority value, (ii) overlap of the first resource and the second resource, and (iii) the priority threshold value for pre-emption checking and a difference between the first priority value and the second priority value.

14. The apparatus of claim 13 , wherein the first priority value is greater than the second priority value, and

wherein the difference between the first priority value and the second priority value exceeds a difference value between the first priority value and the second priority value determined by the priority threshold value.

15. The apparatus of claim 13 , wherein, based on (i) the RSRP value which is greater than the RSRP threshold determined based on the combination of the first priority value and the second priority value, (ii) the overlap of the first resource and the second resource, and (iii) the first priority value which is less than or equal to the second priority value, the resource reselection for the first resource is not performed and the SL transmission is performed by the first UE based on the first resource.