Sensing procedure for sidelink

1. A wireless device comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the wireless device to:

receive one or more first radio resource control (RRC) messages comprising configuration parameters indicating:

a first sensing window of a first sensing procedure;

a second sensing window of a second sensing procedure; and

a threshold value indicating a number of candidate resources for the second sensing procedure;

select, using the first sensing window, a first candidate resource set for one or more sidelink transmissions;

select, using the second sensing window and for the one or more sidelink transmissions, a second candidate resource set from the first selected candidate resource set based on a comparison of a number of candidate resources in the first selected resource set to the threshold; and

transmit the one or more sidelink transmissions via one or more resources of the second candidate resource set.

2. The wireless device of claim 1 , wherein:

the first sensing window is for a first resource selection procedure; and

the second sensing window is for a second resource selection procedure.

3. The wireless device of claim 1 , wherein the second sensing window is for re-evaluation of one or more first resources of the first candidate resource set.

4. The wireless device of claim 1 , wherein the selecting of the second candidate resource set is based on the first sensing window and the second sensing window.

5. The wireless device of claim 1 , wherein the configuration parameters further indicate a selection window.

6. The wireless device of claim 5 , further comprising initializing, based on the first sensing window, the first candidate resource set to comprise candidate resources in the selection window.

7. The wireless device of claim 1 , wherein the selecting the first candidate resource set comprises:

determining a first remaining candidate resource set to comprise one or more first resources based on:

the first candidate resource set; and

first sensing results in the first sensing window.

8. The wireless device of claim 7 , wherein the instructions further cause the wireless device to initialize the second candidate resource set to be the same as the first remaining candidate resource set.

9. A base station comprising:

one or more processors; and

memory storing instructions that, when executed by the one or more processors, cause the base station to:

transmit, to a wireless device, configuration parameters of a sidelink resource pool; and

transmit, to the wireless device, one or more first radio resource control (RRC) messages comprising configuration parameters for one or more sidelink resource pools, wherein the configuration parameters indicate:

a first sensing window of a first sensing procedure for one or more sidelink transmissions, by the wireless device, via the one or more sidelink resource pools;

a second sensing window of a second sensing procedure for the one or more sidelink transmissions, by the wireless device, via the one or more sidelink resource pools; and

a threshold value indicating a number of candidate resources for the second sensing procedure.

10. The base station of claim 9 , wherein:

the first sensing window is for a first resource selection procedure; and

the second sensing window is for a second resource selection procedure.

11. The base station of claim 9 , wherein the second sensing window is for re-evaluation of one or more first resources of a first candidate resource set.

12. The base station of claim 9 , wherein the configuration parameters further indicate a selection window.

13. The base station of claim 9 , wherein the configuration parameters further indicate a set of possible resource reservation periods allowed in the sidelink resource pool.

14. The base station of claim 9 , wherein the configuration parameters further indicate whether sidelink pre-emption is disabled or enabled in the sidelink resource pool.

15. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of a wireless device, cause the wireless device to:

receive one or more first radio resource control (RRC) messages comprising configuration parameters indicating:

a first sensing window of a first sensing procedure;

a second sensing window of a second sensing procedure; and

a threshold value indicating a number of candidate resources for the second sensing procedure;

select, using the first sensing window, a first candidate resource set for one or more sidelink transmissions;

select, using the second sensing window and for the one or more sidelink transmissions, a second candidate resource set from the first selected candidate resource set; and

transmit the one or more sidelink transmissions via one or more resources of the second candidate resource set.

16. The non-transitory computer-readable medium of claim 15 , wherein:

the first sensing window is for a first resource selection procedure; and

the second sensing window is for a second resource selection procedure.

17. The non-transitory computer-readable medium of claim 15 , wherein the second sensing window is for re-evaluation of one or more first resources of the first candidate resource set.

18. The non-transitory computer-readable medium of claim 15 , wherein the selecting of the second candidate resource set is based on the first sensing window and the second sensing window.

19. The wireless device of claim 1 , wherein the second candidate resource set is selected from the first selected candidate resource set in response the number of candidate resources in the selected candidate resource set being greater than the threshold value.

20. The non-transitory computer-readable medium of claim 15 , wherein the second candidate resource set is selected from the first selected candidate resource set in response the number of candidate resources in the selected candidate resource set being greater than the threshold value.