Frequency pre-compensation for high-speed train single frequency networks

1. A method of wireless communications, comprising:

determining, by a base station, a frequency pre-compensation value for a transmission and reception point (TRP) on a single frequency network (SFN);

indicating, by the base station to a user equipment (UE), the frequency pre-compensation value via the TRP; and

applying, by the base station, the frequency pre-compensation value to a signal for transmission by the TRP to the UE.

2. The method of claim 1 , wherein the signal comprises a first signal, and the frequency pre-compensation value comprises a first frequency pre-compensation value associated with a first Transmission Configuration Indicator (TCI) state, further comprising:

determining, by the base station, a second frequency pre-compensation value for the TRP associated with a second TCI state; and

applying, by the base station, the second frequency pre-compensation value to a second signal for transmission by the TRP to the UE.

3. The method of claim 1 , wherein the TRP comprises a first TRP and the frequency pre-compensation value comprises a first frequency pre-compensation value, the method further comprising:

determining, by the base station, a second frequency pre-compensation value for a second TRP on the SFN for use with the signal;

indicating, by the base station, the second frequency pre-compensation value to the UE via the first TRP or the second TRP; and

applying, by the base station, the second frequency pre-compensation value to the signal for transmission by the second TRP to the UE.

4. The method of claim 1 , wherein an indication of the frequency pre-compensation value is included, by the base station, in a downlink control information (DCI) message.

5. The method of claim 1 , wherein the frequency pre-compensation value is determined based on a frequency measurement of a reference signal from the UE.

6. The method of claim 1 , wherein the frequency pre-compensation value is determined based on a frequency measurement of a reference signal from the base station.

7. The method of claim 1 , further comprising:

updating, by the base station, the frequency pre-compensation value in response to a change in the SFN; and

indicating, by the base station to the UE, the updated frequency pre-compensation value via the TRP.

8. A method of wireless communications, comprising:

receiving, by a user equipment (UE) on a single frequency network (SFN), an indication of a frequency pre-compensation value for used by a transmission and reception point (TRP);

receiving, by the UE, a signal modified by the frequency pre-compensation value;

narrowing, by the UE, a range of a tracking loop based on the indicated frequency pre-compensation value; and

performing, by the UE, channel estimation of the signal based on the narrowed tracking loop.

9. The method of claim 8 , wherein the signal comprises a first signal, and the indication of a frequency pre-compensation value comprises a first indication of a first frequency pre-compensation value associated with a first Transmission Configuration Indicator (TCI) state, further comprising:

receiving, by the UE from the TRP, a second indication of a second frequency pre-compensation value associated with a second TCI state for use by the TRP; and

receiving, by the UE from the TRP, a second signal modified by the second frequency pre-compensation value;

wherein the narrowing is further based on the second indicated frequency pre-compensation value.

10. The method of claim 8 , wherein the TRP comprises a first TRP, the receiving the signal further comprising receiving the signal from a second TRP as well as the first TRP.

11. The method of claim 10 , wherein the frequency pre-compensation value comprises a first frequency pre-compensation value, the receiving the frequency pre-compensation value further comprising:

receiving, by the UE from a second TRP, an indication of a second frequency pre-compensation value for use by the second TRP.

12. The method of claim 11 , wherein the narrowing is based on the second frequency pre-compensation value as well as the first frequency pre-compensation value.

13. The method of claim 8 , wherein the indication is part of a downlink control information (DCI) message.

14. The method of claim 8 , wherein the frequency pre-compensation value is determined based on a frequency measurement of a reference signal from the UE.

15. The method of claim 8 , wherein the frequency pre-compensation value is determined based on a frequency measurement of a reference signal from the TRP.

16. A base station, comprising:

a memory;

a transceiver; and

a processor coupled with the memory and the transceiver and configured, when executing instructions stored on the memory, to cause the base station to:

determine a frequency pre-compensation value for a transmission and reception point (TRP) on a single frequency network (SFN);

indicate to a user equipment (UE) the frequency pre-compensation value via the TRP; and

apply the frequency pre-compensation value to a signal for transmission by the TRP to the UE.

17. The base station of claim 16 , wherein the signal comprises a first signal, and the frequency pre-compensation value comprises a first frequency pre-compensation value associated with a first Transmission Configuration Indicator (TCI) state, the transceiver and the processor further configured to:

determine a second frequency pre-compensation value for the TRP associated with a second TCI state; and

apply the second frequency pre-compensation value to a second signal for transmission by the TRP to the UE.

18. The base station of claim 16 , wherein the TRP comprises a first TRP, the frequency pre-compensation value comprises a first frequency pre-compensation value, and the transceiver and the processor are further configured to:

determine a second frequency pre-compensation value for a second TRP on the SFN for use with the signal;

indicate the second frequency pre-compensation value to the UE via the first TRP or the second TRP; and

apply the second frequency pre-compensation value to the signal for transmission by the second TRP to the UE.

19. The base station of claim 16 , wherein the transceiver and the processor are configured to indicate the frequency pre-compensation value by:

including an indication of the frequency pre-compensation value in a downlink control information (DCI) message.

20. The base station of claim 16 , wherein the transceiver and the processor are configured to determine the frequency pre-compensation value by:

estimating the frequency pre-compensation value based on a measurement, by the TRP, of a reference signal from the UE.

21. The base station of claim 16 , wherein the transceiver and the processor are configured to determine the frequency pre-compensation value by:

estimating the frequency pre-compensation value based on a measurement, by the UE, of a reference signal from the base station.

22. The base station of claim 16 , wherein the transceiver and the processor are further configured to:

update the frequency pre-compensation value in response to a change in the SFN; and

indicate to the UE the updated frequency pre-compensation value via the TRP.

23. A user equipment (UE), comprising:

a memory;

a transceiver; and

a processor coupled with the memory and the transceiver and configured, when executing instructions stored on the memory, to cause the UE to:

receive on a single frequency network (SFN) an indication of a frequency pre-compensation value for use by a transmission and reception point (TRP);

receive a signal modified by the frequency pre-compensation value;

narrow range of a tracking loop based on the indicated frequency pre-compensation value; and

perform channel estimation of the signal based on the narrowed tracking loop.

24. The UE of claim 23 , wherein the signal comprises a first signal, and the indication of a frequency pre-compensation value comprises a first indication of a first frequency pre-compensation value associated with a first Transmission Configuration Indicator (TCI) state, the transceiver and the processor further configured to:

receive, from the TRP, a second indication of a second frequency pre-compensation value associated with a second TCI state for use by the TRP; and

receive, from the TRP, a second signal modified by the second frequency pre-compensation value; and

narrow range of the tracking loop further based on the second indicated frequency pre-compensation value.

25. The UE of claim 23 , wherein the TRP comprises a first TRP, and the transceiver and the processor are configured to receive the signal by receiving the signal from a second TRP as well as the first TRP.

26. The UE of claim 25 , wherein the frequency pre-compensation value comprises a first frequency pre-compensation value, and the transceiver and the processor are further configured to receive an indication of a second frequency pre-compensation value from the second TRP.

27. The UE of claim 26 , wherein the narrowing is based on the second frequency pre-compensation value as well as the first frequency pre-compensation value.

28. The UE of claim 23 , wherein the indication is part of a downlink control information (DCI) message.

29. The UE of claim 23 , wherein the frequency pre-compensation value is determined based on a frequency measurement, by the TRP, of a reference signal from the UE.

30. The UE of claim 23 , wherein the frequency pre-compensation value is determined based on a frequency measurement, by the UE, of a reference signal from the TRP.