Methods and apparatus related to time tracking in multi carrier systems

1. A method of wireless communication of a first network, comprising:

receiving, at a base station, user equipment (UE) capability information from each UE of a plurality of UEs, the UE capability information received from each UE indicating at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

determining, for the plurality of UEs, a set of synchronization-timing priorities based on the received UE capability information, the set of synchronization-timing priorities indicating a priority for timing synchronization types for use within each carrier of a set of carriers of the plurality of carriers; and

broadcasting, from the base station, the determined set of synchronization-timing priorities to the plurality of UEs.

2. The method of claim 1 , wherein:

the plurality of UEs is associated with the first network,

the method further comprises receiving at least one of UE capability information or synchronization-timing priority information associated with a second plurality of UEs from a second network different than the first network, the plurality of different networks including the second network, and

the set of synchronization-timing priorities for the plurality of UEs is further determined based on the at least one of the UE capability information or the synchronization-timing priority information associated with the second plurality of UEs from the second network.

3. The method of claim 1 , wherein the UE capability information from each UE of the plurality of UEs indicates a first number of different transmission carrier synchronization timings that the UE can track within the plurality of carriers and a second number of different reception carrier synchronization timings that the UE can track within the plurality of carriers.

4. The method of claim 1 , wherein the determined set of synchronization-timing priorities is broadcasted in a system information block (SIB) to the plurality of UEs.

5. The method of claim 1 , further comprising:

determining, for the plurality of UEs, a carrier priority based on the received UE capability information, the carrier priority indicating how to prioritize different carriers of the plurality of carriers for data transmission or reception; and

broadcasting the carrier priority to the plurality of UEs.

6. The method of claim 1 , wherein the first network, the base station, and the plurality of UEs support vehicle-to-everything sidelink communications.

7. A method of wireless communication of a user equipment (UE) associated with a first network, comprising:

determining a UE capability of the UE associated with at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

sending the determined UE capability to a base station;

receiving, from the base station, a set of synchronization-timing priorities for prioritizing timing synchronization types within each carrier of a set of carriers of the plurality of carriers; and

synchronizing, for each carrier of the set of carriers, a timing based on the received set of synchronization-timing priorities.

8. The method of claim 7 , wherein the determined UE capability includes a first UE capability associated with a first number of different transmission carrier synchronization timings that the UE can track within the plurality of carriers, and includes a second UE capability associated with a second number of different reception carrier synchronization timings that the UE can track within the plurality of carriers.

9. The method of claim 7 , further comprising:

receiving, from the base station, information indicating a carrier priority indicating how to prioritize different carriers of the plurality of carriers for data transmission or reception; and

prioritizing carriers of the plurality of carriers for data transmission or reception based on the received information indicating the carrier priority when a number of a subset of the timing synchronization types in each priority of the set of synchronization-timing priorities is greater than the number of different carrier synchronization timings that the UE can track.

10. The method of claim 7 , wherein the UE and the first network support vehicle-to-everything sidelink communications.

11. An apparatus of wireless communication of a first network, comprising:

means for receiving user equipment (UE) capability information from each UE of a plurality of UEs, the UE capability information received from each UE indicating at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

means for determining, for the plurality of UEs, a set of synchronization-timing priorities based on the received UE capability information, the set of synchronization-timing priorities indicating a priority for timing synchronization types for use within each carrier of a set of carriers of the plurality of carriers; and

means for broadcasting the determined set of synchronization-timing priorities to the plurality of UEs.

12. The apparatus of claim 11 , wherein:

the plurality of UEs is associated with the first network,

the means for receiving is further configured to receive at least one of UE capability information or synchronization-timing priority information associated with a second plurality of UEs from a second network different than the first network, the plurality of different networks including the second network, and

the means for determining is configured to determine the set of synchronization-timing priorities for the plurality of UEs further based on the at least one of the UE capability information or the synchronization-timing priority information associated with the second plurality of UEs from the second network.

13. The apparatus of claim 11 , wherein the UE capability information from each UE of the plurality of UEs indicates a first number of different transmission carrier synchronization timings that the UE can track within the plurality of carriers and a second number of different reception carrier synchronization timings that the UE can track within the plurality of carriers.

14. The apparatus of claim 11 , wherein the determined set of synchronization-timing priorities is broadcasted in a system information block (SIB) to the plurality of UEs.

15. The apparatus of claim 11 , further comprising:

means for determining, for the plurality of UEs, a carrier priority based on the received UE capability information, the carrier priority indicating how to prioritize different carriers of the plurality of carriers for data transmission or reception; and

wherein the means for broadcasting is further configured to broadcast the carrier priority to the plurality of UEs.

16. An apparatus of wireless communication of a first network, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

receive user equipment (UE) capability information from each UE of a plurality of UEs, the UE capability information received from each UE indicating at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

determine, for the plurality of UEs, a set of synchronization-timing priorities based on the received UE capability information, the set of synchronization-timing priorities indicating a priority for timing synchronization types for use within each carrier of a set of carriers of the plurality of carriers; and

broadcast the determined set of synchronization-timing priorities to the plurality of UEs.

17. The apparatus of claim 16 ,

wherein the plurality of UEs is associated with the first network;

wherein the at least one processor is further configured to:

receive at least one of UE capability information or synchronization-timing priority information associated with a second plurality of UEs from a second network different than the first network, the plurality of different networks including the second network; and

determine the set of synchronization-timing priorities for the plurality of UEs further based on the at least one of the UE capability information or the synchronization-timing priority information associated with the second plurality of UEs from the second network.

18. The apparatus of claim 16 , wherein the UE capability information from each UE of the plurality of UEs indicates a first number of different transmission carrier synchronization timings that the UE can track within the plurality of carriers and a second number of different reception carrier synchronization timings that the UE can track within the plurality of carriers.

19. The apparatus of claim 16 , wherein the determined set of synchronization-timing priorities is broadcasted in a system information block (SIB) to the plurality of UEs.

20. The apparatus of claim 16 , wherein the at least one processor is further configured to:

determine, for the plurality of UEs, a carrier priority based on the received UE capability information, the carrier priority indicating how to prioritize different carriers of the plurality of carriers for data transmission or reception; and

broadcast the carrier priority to the plurality of UEs.

21. The apparatus of claim 16 , wherein the apparatus and the first network support vehicle-to-everything sidelink communications.

22. A non-transitory computer-readable medium of an apparatus in a first network, the computer-readable medium storing computer executable code executed by a processor, said code is configured to:

receive user equipment (UE) capability information from each UE of a plurality of UEs, the UE capability information received from each UE indicating at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

determine, for the plurality of UEs, a set of synchronization-timing priorities based on the received UE capability information, the set of synchronization-timing priorities indicating a priority for timing synchronization types for use within each carrier of a set of carriers of the plurality of carriers; and

broadcast the determined set of synchronization-timing priorities to the plurality of UEs.

23. A user equipment (UE) associated with a first network, comprising:

means for determining a UE capability of the UE associated with at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

means for sending the determined UE capability to a base station;

means for receiving, from the base station, a set of synchronization-timing priorities for prioritizing timing synchronization types within each carrier of a set of carriers of the plurality of carriers; and

means for synchronizing, for each carrier of the set of carriers, a timing based on the received set of synchronization-timing priorities.

24. The UE of claim 23 , wherein the determined UE capability includes a first UE capability associated with a first number of different transmission carrier synchronization timings that the UE can track within the plurality of carriers, and includes a second UE capability associated with a second number of different reception carrier synchronization timings that the UE can track within the plurality of carriers.

25. The UE of claim 23 ,

wherein the means for receiving is further configured to receive, from the base station, information indicating a carrier priority indicating how to prioritize different carriers of the plurality of carriers for data transmission or reception; and

wherein the UE further comprises means for prioritizing carriers of the plurality of carriers for data transmission or reception based on the received information indicating the carrier priority, the prioritizing being performed when a number of a subset of the timing synchronization types in each priority of the set of synchronization-timing priorities is greater than the number of different carrier synchronization timings that the UE can track.

26. A user equipment (UE) associated with a first network, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

determine a UE capability of the UE associated with at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

send the determined UE capability to a base station;

receive, from the base station, a set of synchronization-timing priorities for prioritizing timing synchronization types within each carrier of a set of carriers of the plurality of carriers; and

synchronize, for each carrier of the set of carriers, a timing based on the received set of synchronization-timing priorities.

27. The UE of claim 26 , wherein the determined UE capability includes a first UE capability associated with a first number of different transmission carrier synchronization timings that the UE can track within the plurality of carriers, and includes a second UE capability associated with a second number of different reception carrier synchronization timings that the UE can track within the plurality of carriers.

28. The UE of claim 26 , wherein the at least one processor is further configured to:

receive, from the base station, information indicating a carrier priority indicating how to prioritize different carriers of the plurality of carriers for data transmission or reception; and

prioritize carriers of the plurality of carriers for data transmission or reception based on the received information indicating the carrier priority when a number of a subset of the timing synchronization types in each priority of the set of synchronization-timing priorities is greater than the number of different carrier synchronization timings that the UE can track.

29. The UE of claim 26 , wherein the UE and the first network support vehicle-to-everything sidelink communications.

30. A non-transitory computer-readable medium of a user equipment associated with a first network, the computer-readable medium storing computer executable code executed by a processor, said code is configured to:

determine a UE capability of the UE associated with at least a number of different carrier synchronization timings that the UE can track within a plurality of carriers, the plurality of carriers being associated with a plurality of different networks including the first network;

send the determined UE capability to a base station;

receive, from the base station, a set of synchronization-timing priorities for prioritizing timing synchronization types within each carrier of a set of carriers of the plurality of carriers; and

synchronize, for each carrier of the set of carriers, a timing based on the received set of synchronization-timing priorities.