Sidelink channel state information acquisition

1. A method comprising:

receiving, by a first wireless device from a second wireless device, one or more configuration messages comprising a sidelink latency upper bound for sidelink channel state information (CSI) reporting;

receiving, during a first time slot, by the first wireless device from the second wireless device:

a sidelink CSI reporting triggering indication via a physical sidelink control channel, and

one or more CSI reference signals via a physical sidelink shared channel;

determining, by the first wireless device and based on receiving both the sidelink CSI reporting triggering indication and the one or more CSI reference signals during the first time slot, one or more sidelink CSI reporting resources within a time period indicated by:

the sidelink latency upper bound, and

starting from the first time slot; and

transmitting, by the first wireless device, one or more sidelink CSIs on the one or more sidelink CSI reporting resources.

2. The method of claim 1 , wherein a frequency resource block size of the one or more CSI reference signals is equal to a frequency resource block size of one or more physical sidelink shared channels (PSSCHs) being transmitted with the one or more CSI reference signals.

3. The method of claim 1 , wherein the sidelink CSI reporting triggering indication is received via sidelink control information.

4. The method of claim 3 , wherein the sidelink control information is second stage sidelink control information.

5. The method of claim 4 , wherein the second stage sidelink control information is received via a PSSCH.

6. The method of claim 1 , wherein the one or more configuration messages are received via one or more sidelink radio resource control messages (RRCs).

7. The method of claim 1 , wherein the one or more sidelink CSIs comprise one or more channel quality indicators and one or more rank indicators.

8. The method of claim 1 , further comprising determining the one or more sidelink CSIs based on the one or more CSI reference signals.

9. The method of claim 1 , wherein the one or more sidelink CSIs are transmitted via a sidelink medium access control control element (MAC CE).

10. The method of claim 1 , wherein the first wireless device and the second wireless device are a pair in a unicast group.

11. 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, one or more configuration messages comprising a sidelink latency upper bound for sidelink channel state information (CSI) reporting;

receive, during a first time slot, from the second wireless device:

a sidelink CSI reporting triggering indication via a physical sidelink control channel, and

one or more CSI reference signals via a physical sidelink shared channel;

determine, based on receiving both the sidelink CSI reporting triggering indication and the one or more CSI reference signals during the first time slot, one or more sidelink CSI reporting resources within a time period indicated by:

the sidelink latency upper bound, and

starting from the first time slot; and

transmit one or more sidelink CSIs on the one or more sidelink CSI reporting resources.

12. The first wireless device of claim 11 , wherein a frequency resource block size of the one or more CSI reference signals is equal to a frequency resource block size of one or more physical sidelink shared channels (PSSCHs) being transmitted with the one or more CSI reference signals.

13. The first wireless device of claim 11 , wherein the sidelink CSI reporting triggering indication is received via sidelink control information.

14. The first wireless device of claim 13 , wherein the sidelink control information is second stage sidelink control information.

15. The first wireless device of claim 14 , wherein the second stage sidelink control information is received via a PSSCH.

16. The first wireless device of claim 11 , wherein the one or more configuration messages are received via one or more sidelink radio resource control messages (RRCs).

17. The first wireless device of claim 11 , wherein the one or more sidelink CSIs comprise one or more channel quality indicators and one or more rank indicators.

18. The first wireless device of claim 11 , wherein the instructions, when executed by the one or more processors, further cause the first wireless device to determine the one or more sidelink CSIs based on the one or more CSI reference signals.

19. The first wireless device of claim 11 , wherein the one or more sidelink CSIs are transmitted via a sidelink medium access control control element (MAC CE).

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

receive, from a second wireless device, one or more configuration messages comprising a sidelink latency upper bound for sidelink channel state information (CSI) reporting;

receive, during a first time slot, from the second wireless device:

a sidelink CSI reporting triggering indication via a physical sidelink control channel, and

one or more CSI reference signals via a physical sidelink shared channel;

determine, based on receiving both the sidelink CSI reporting triggering indication and the one or more CSI reference signals during the first time slot, one or more sidelink CSI reporting resources within a time period indicated by:

the sidelink latency upper bound, and

starting from the first time slot; and

transmit one or more sidelink CSIs on the one or more sidelink CSI reporting resources.