Time synchronization accuracy enhancements

1. A baseband processor for a User Equipment (UE), configured to:

decode a unicast message from a base station received through a radio interface, the unicast message including reference time information and an indication that the reference time information corresponds to a pre-compensated reference time that has been pre-compensated, prior to reception of the unicast message from the base station, for propagation delay between a receiver of the UE and a transmitter of the base station;

in response to the indication, determine a reference time from the reference time information without applying compensation for propagation delay thereto; and

cause the UE to communicate with the base station based on the reference time.

2. The baseband processor of claim 1 , further configured to:

in response to the unicast message not including an indication of a range of inaccuracy in the pre-compensated reference time determine the reference time without using any range of inaccuracy associated with the pre-compensated reference time.

3. The baseband processor of claim 1 , wherein the baseband processor is configured to further decode a compensation offset signal from the base station, the signal including a field indicating a compensation offset for the reference time, the signal further being based on an estimated DL propagation delay specific to the UE and being separate from the unicast message.

4. The baseband processor of claim 1 , wherein the reference time information includes an indication of at least one of an accuracy and of a granularity associated with the reference time, wherein the baseband processor is configured to further:

decode a downlink (DL) propagation delay compensation signal from the base station; and determine, based on the DL propagation delay compensation signal, whether to perform a DL propagation delay compensation in determining the reference time.

5. The baseband processor of claim 4 , wherein, in response to a determination that the DL propagation delay compensation signal indicates to perform the DL propagation delay compensation, the baseband processor is configured to perform the DL propagation delay compensation using timing advance (TA) information.

6. The baseband processor of claim 1 , wherein the baseband processor is configured to further decode a timing advance (TA) command field from the base station, the TA command field having a bit-width of 12 bits, and including TA information with a granularity having a value of K·64·T 0 /2 m , wherein K is less than 16, and wherein T c corresponds to a basic time unit for NR.

7. The baseband processor of claim 6 , wherein the TA information includes a reduced maximum TA value that is less than 3846·16·64/2 m , the reduced maximum TA value using an increased number of bits of the bit-width.

8. The baseband processor of claim 1 , wherein the baseband processor is configured to:

prioritize a unicast signaling technique over a broadcast signaling technique;

decode a first reference time information in a system information block (SIB) message sent by the base station via the broadcast signaling technique;

determine whether a second reference time information is received by the UE within a time window, the second reference time information sent by the base station via the unicast signaling technique;

prioritize the second reference time information in response to a determination that the second reference time information was received by the UE within the time window; and

refrain from prioritizing the second reference time information in response to a determination that the second reference time information was not received by the UE within the time window.

9. The baseband processor of claim 1 , wherein the unicast message includes dedicated radio resource control signaling.

10. A method for a User Equipment (UE), comprising:

receiving a unicast message from a base station, the unicast message including reference time information and an indication that the reference time information corresponds to a pre-compensated reference time that has been pre-compensated, prior to reception of the unicast message from the base station, for propagation delay between a receiver of the UE and a transmitter of the base station;

in response to the indication, determining a reference time from the reference time information without applying compensation for propagation delay thereto; and

causing the UE to communicate with the base station based on the reference time.

11. The method of claim 10 , further comprising:

in response to the unicast message not including an indication of a range of inaccuracy in the pre-compensated reference time, determining the reference time without using any range of inaccuracy associated with the pre-compensated reference time.

12. The method of claim 10 , further comprising:

receiving a compensation offset signal from the base station, the signal including a field indicating a compensation offset for the reference time, the signal further being based on an estimated DL propagation delay specific to the UE and being separate from the unicast message.

13. The method of claim 10 , wherein the reference time information includes an indication of at least one of an accuracy and of a granularity associated with the reference time, the method further comprising:

receiving a downlink (DL) propagation delay compensation signal from the base station; and

determining, based on the DL propagation delay compensation signal, whether to perform a DL propagation delay compensation in determining the reference time.

14. The method of claim 13 , further comprising:

in response to a determination that the DL propagation delay compensation signal indicates to perform the DL propagation delay compensation, performing the DL propagation delay compensation using timing advance (TA) information.

15. The method of claim 10 , further comprising:

receiving a timing advance (TA) command field from the base station, the TA command field having a bit-width of 12 bits, and including TA information with a granularity having a value of K·64·T 0 /2 m , wherein K is less than 16, and wherein T c corresponds to a basic time unit for NR.

16. A User Equipment (UE), comprising:

a memory;

radio front end circuitry; and

processor circuitry coupled to the radio front end circuitry and coupled to the memory, wherein the processor circuitry is configured to execute instructions stored in the memory to cause the UE to:

receive, via the radio front end circuitry, a unicast message from a base station, the unicast message including reference time information and an indication that the reference time information corresponds to a pre-compensated reference time that has been pre-compensated, prior to reception of the unicast message from the base station, for propagation delay between a receiver of the UE and a transmitter of the base station;

in response to the indication, determine a reference time from the reference time information without applying compensation for propagation delay thereto; and

communicate with the base station based on the reference time.

17. The UE of claim 16 , wherein the processor circuitry is further configured to cause the UE to:

receive a timing advance (TA) command field from the base station, the TA command field having a bit-width of 12 bits, and including TA information with a granularity having a value of K·64·T 0 /2 m , wherein K is less than 16, and wherein T c corresponds to a basic time unit for NR.

18. The UE of claim 17 , wherein the TA information includes a reduced maximum TA value that is less than 3846·16·64/2 m , the reduced maximum TA value using an increased number of bits of the bit-width.

19. The UE of claim 16 , wherein the processor circuitry is further configured to cause the UE to:

prioritize a unicast signaling technique over a broadcast signaling technique;

receive a first reference time information in a system information block (SIB) message sent by the base station via the broadcast signaling technique;

determine whether a second reference time information is received by the UE within a time window, the second reference time information sent by the base station via the unicast signaling technique;

prioritize the second reference time information in response to a determination that the second reference time information was received by the UE within the time window; and

refrain from prioritizing the second reference time information in response to a determination that the second reference time information was not received by the UE within the time window.

20. The UE of claim 16 , wherein the unicast message includes dedicated radio resource control signaling.