Selection window determination for sidelink inter-UE coordination

1. A method comprising:

receiving, by a first wireless device from a second wireless device, a first message indicating a first reference time of a selection window for the second wireless device to select resources for one or more sidelink transmissions by the second wireless device, wherein the selection window is based on a second resource selection procedure of the second wireless device for the one or more sidelink transmissions;

selecting, by the first wireless device, a first set of resources during the selection window based on the first reference time; and

transmitting, to the second wireless device, a second message indicating the first set of resources for the second wireless device to select the resources for the one or more sidelink transmissions.

2. The method of claim 1 , wherein:

the first reference time is an end time, n+T2, of the selection window;

a slot with a slot index n indicates a time for triggering the second resource selection procedure by the second wireless device for the one or more sidelink transmissions; and

T2 is determined by the second wireless device, based on T2≥T2 min, wherein T2 min is associated with a priority value of the one or more sidelink transmissions.

3. The method of claim 1 , wherein the first reference time is based on a first slot index.

4. The method of claim 2 , wherein the first message further indicates a second reference time of the selection window.

5. The method of claim 4 , wherein:

the second reference time is a start time, n+T1, of the selection window;

T1 is determined, by the second wireless device, based on T1≤T proc,1 ; and

T proc,1 is a maximum processing latency for completing the second resource selection procedure being triggered at the slot index n for the one or more sidelink transmissions.

6. The method of claim 4 , wherein the second reference time is indicated by a second slot index.

7. The method of claim 1 , further comprising determining, by the first wireless device and based on the first message, the selection window.

8. The method of claim 1 , wherein the selecting of the first set of resources in the selection window is based on a first resource selection procedure.

9. The method of claim 1 , wherein the first message comprises at least one of:

a first medium access control (MAC) control element (CE); or

a first sidelink control information (SCI).

10. A first wireless device comprising:

one or more processors; and

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

receive, from a second wireless device, a first message indicating a first reference time of a selection window for the second wireless device to select resources for one or more sidelink transmissions by the second wireless device, wherein the selection window is based on a second resource selection procedure of the second wireless device for the one or more sidelink transmissions;

select, by the first wireless device, a first set of resources during the selection window based on the first reference time; and

transmit, to the second wireless device, a second message indicating the first set of resources for the second wireless device to select the resources for the one or more sidelink transmissions.

11. The first wireless device of claim 10 , wherein:

the first reference time is an end time, n+T2, of the selection window;

a slot with a slot index n indicates a time for triggering the second resource selection procedure by the second wireless device for the one or more sidelink transmissions; and

T2 is determined by the second wireless device, based on T2≥T2 min, wherein T2 min is associated with a priority value of the one or more sidelink transmissions.

12. The first wireless device of claim 10 , wherein the first reference time is based on a first slot index.

13. The first wireless device of claim 11 , wherein the first message further indicates a second reference time of the selection window.

14. The first wireless device of claim 13 , wherein:

the second reference time is a start time, n+T1, of the selection window;

T1 is determined, by the second wireless device, based on T1≤T proc,1 ; and

T proc,1 is a maximum processing latency for completing the second resource selection procedure being triggered at the slot index n for the one or more sidelink transmissions.

15. The first wireless device of claim 13 , wherein the second reference time is indicated by a second slot index.

16. The first wireless device of claim 10 , wherein the instructions further cause the first wireless device to determine, based on the first message, the selection window.

17. The first wireless device of claim 10 , wherein the selecting of the first set of resources in the selection window is based on a first resource selection procedure.

18. A system comprising:

a first wireless device; and

a second wireless device, wherein:

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

transmit, to the second wireless device, a first message indicating a first reference time of a selection window for the second wireless device to select resources for one or more sidelink transmissions by the first wireless device; and

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

receive, from the first wireless device, the first message indicating the first reference time of the selection window for the second wireless device to select the resources for the one or more sidelink transmissions by the first wireless device, wherein the selection window is based on a second resource selection procedure of the second wireless device for the one or more sidelink transmissions;

select a first set of resources during the selection window based on the first reference time; and

transmit, to the first wireless device, a second message indicating the first set of resources for the first wireless device to select the resources for the one or more sidelink transmissions.