Cyclic shift reporting for a reference signal

1. A method for wireless communications at a user equipment (UE), comprising:

transmitting, to a network entity, a capability message indicating a capability of the UE to report a cyclic shift for a reference signal;

receiving, from the network entity, an indication of a reporting configuration based at least in part on the capability, the reporting configuration indicating uplink resources for reporting the cyclic shift by the UE;

receiving one or more reference signals from the network entity; and

transmitting, to the network entity and using the uplink resources, an uplink message indicating the cyclic shift, wherein the cyclic shift is based at least in part on a channel delay spread measurement by the UE of the one or more reference signals.

2. The method of claim 1 , further comprising:

measuring a channel delay spread of the one or more reference signals, a phase noise mask of the one or more reference signals, or both based at least in part on receiving the one or more reference signals; and

estimating the cyclic shift based at least in part on the channel delay spread measurement, the phase noise mask measurement, or both.

3. The method of claim 2 , further comprising:

estimating the cyclic shift based at least in part on applying a back-off to a cyclic prefix associated with the one or more reference signals.

4. The method of claim 1 , wherein transmitting the uplink message indicating the cyclic shift comprises:

transmitting the uplink message indicating a number of samples of the cyclic shift, a direction of the cyclic shift, or both.

5. The method of claim 4 , wherein the uplink message comprises a shared channel message comprising a quantity of bits indicating the number of samples of the cyclic shift, the direction of the cyclic shift, or both.

6. The method of claim 1 , further comprising:

receiving, from the network entity, a control message indicating that the network entity applied the cyclic shift indicated by the uplink message.

7. The method of claim 1 , further comprising:

receiving, from the network entity, a control message indicating that the network entity applied a cyclic shift different from the cyclic shift indicated by the uplink message.

8. The method of claim 1 , further comprising:

transmitting, to the network entity, a request for the network entity to update the applied cyclic shift based at least in part on the applied cyclic shift being different from the cyclic shift indicated in the uplink message.

9. The method of claim 1 , further comprising:

selecting the uplink resources for reporting the cyclic shift based at least in part on the capability of the UE to report the cyclic shift for the reference signal.

10. The method of claim 1 , wherein transmitting the uplink message indicating the cyclic shift comprises:

transmitting the uplink message indicating the cyclic shift according to a periodicity based at least in part on the reporting configuration.

11. The method of claim 1 , wherein transmitting the uplink message indicating the cyclic shift comprises:

transmitting the uplink message indicating the cyclic shift aperiodically based at least in part on the reporting configuration.

12. The method of claim 1 , wherein transmitting the uplink message indicating the cyclic shift comprises:

transmitting the uplink message indicating the cyclic shift via a shared channel, a control channel, channel state information, or any combination thereof.

13. The method of claim 1 , wherein transmitting the capability message comprises:

transmitting, to the network entity, a radio resource control message indicating the capability of the UE to report the cyclic shift for the reference signal.

14. The method of claim 1 , wherein transmitting the uplink message indicating the cyclic shift comprises:

transmitting the uplink message indicating the cyclic shift a number of reference signal groups for location squeezing based at least in part on a phase noise associated with the one or more reference signals.

15. The method of claim 1 , wherein the one or more reference signals comprises a time-domain phase tracking reference signal, a demodulation reference signal, a channel state information reference signal, or any combination thereof.

16. A method for wireless communications at a network entity, comprising:

receiving, from a user equipment (UE), a capability message indicating a capability of the UE to report a cyclic shift for a reference signal;

transmitting, to the UE, an indication of a reporting configuration based at least in part on the capability, the reporting configuration indicating uplink resources for reporting the cyclic shift by the UE;

transmitting one or more reference signals to the UE; and

receiving, from the UE and using the uplink resources, an uplink message indicating the cyclic shift, wherein the cyclic shift is based at least in part on a channel delay spread measurement by the UE of the one or more reference signals.

17. The method of claim 16 , wherein receiving the uplink message indicating the cyclic shift comprises:

receiving the uplink message indicating a number of samples of the cyclic shift, a direction of the cyclic shift, or both.

18. The method of claim 17 , wherein the uplink message comprises a shared channel message comprising a quantity of bits indicating the number of samples of the cyclic shift, the direction of the cyclic shift, or both.

19. The method of claim 16 , wherein receiving the uplink message indicating the cyclic shift comprises:

transmitting the uplink message indicating the cyclic shift a number of reference signal groups for location squeezing based at least in part on a phase noise associated with the one or more reference signals.

20. The method of claim 16 , further comprising:

applying the cyclic shift to the one or more reference signals; and

transmitting, to the UE, a control message indicating that the network entity applied the cyclic shift indicated by the uplink message.

21. The method of claim 16 , further comprising:

transmitting, to the UE, a control message indicating that the network entity applied a cyclic shift different from the cyclic shift indicated by the uplink message.

22. The method of claim 21 , further comprising:

receiving, from the UE, a request for the network entity to update the applied cyclic shift based at least in part on the applied cyclic shift being different from the cyclic shift indicated in the uplink message.

23. The method of claim 16 , wherein receiving the uplink message indicating the cyclic shift comprises:

receiving the uplink message indicating the cyclic shift according to a periodicity based at least in part on the reporting configuration.

24. The method of claim 16 , wherein receiving the uplink message indicating the cyclic shift comprises:

receiving the uplink message indicating the cyclic shift aperiodically based at least in part on the reporting configuration.

25. The method of claim 16 , wherein receiving the uplink message indicating the cyclic shift comprises:

receiving the uplink message indicating the cyclic shift via a shared channel, a control channel, channel state information, or any combination thereof.

26. The method of claim 16 , wherein receiving the capability message comprises:

receiving, from the UE, a radio resource control message indicating the capability of the UE to report the cyclic shift for the reference signal.

27. The method of claim 16 , wherein the one or more reference signals comprises a time-domain phase tracking reference signal, a demodulation reference signal, a channel state information reference signal, or any combination thereof.

28. An apparatus for wireless communications at a user equipment (UE), comprising:

a processor;

memory coupled with the processor; and

one or more instructions stored in the memory and executable by the processor to cause the apparatus to, based at least in part on the one or more instructions:

transmit, to a network entity, a capability message indicating a capability of the UE to report a cyclic shift for a reference signal;

receive, from the network entity, an indication of a reporting configuration based at least in part on the capability, the reporting configuration indicating uplink resources for reporting the cyclic shift by the UE;

receive one or more reference signals from the network entity; and

transmit, to the network entity and using the uplink resources, an uplink message indicating the cyclic shift, wherein the cyclic shift is based at least in part on a channel delay spread measurement by the UE of the one or more reference signals.

29. The apparatus of claim 28 , wherein the instructions are further executable by the processor to cause the apparatus to:

measure a channel delay spread of the one or more reference signals, a phase noise mask of the one or more reference signals, or both based at least in part on receiving the one or more reference signals; and

estimate the cyclic shift based at least in part on the channel delay spread measurement, the phase noise mask measurement, or both.

30. An apparatus for wireless communications at a network entity, comprising:

a processor;

memory coupled with the processor; and

one or more instructions stored in the memory and executable by the processor to cause the apparatus to, based at least in part on the one or more instructions:

receive, from a user equipment (UE), a capability message indicating a capability of the UE to report a cyclic shift for a reference signal;

transmit, to the UE, an indication of a reporting configuration based at least in part on the capability, the reporting configuration indicating uplink resources for reporting the cyclic shift by the UE;

transmit one or more reference signals to the UE; and

receive, from the UE and using the uplink resources, an uplink message indicating the cyclic shift, wherein the cyclic shift is based at least in part on a channel delay spread measurement by the UE of the one or more reference signals.