Methods and apparatuses for sidelink operations

1. A user equipment (UE), comprising:

one or more non-transitory computer-readable media having computer-executable instructions embodied therein; and

at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the computer-executable instructions to cause the UE to:

receive an indicator indicating that Long-Term-Evolution (LTE)-Vehicle to Everything (V2X) sidelink (SL) communication is shared with New Radio (NR) SL communication on at least a first carrier frequency in one or more carrier frequencies, the indicator including a radio access technology (RAT)-shared bit associated with the first carrier frequency in an NR SL frequency carrier configuration;

select a second carrier frequency in the one or more carrier frequencies for the NR SL communication; and

in a case that the second carrier frequency is the same as the first carrier frequency, implement a frequency shift on the second carrier frequency while performing one or more NR SL transmissions.

2. The UE of claim 1 , wherein the indicator is received through one of:

an SL pre-configuration;

an SL configuration received from a serving cell through a Uu interface; or

an SL configuration received from another UE via a PC5 air interface through Radio Resource Control (RRC) signaling.

3. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to cause the UE to:

in the case that the second carrier frequency is the same as the first carrier frequency, implement the frequency shift on the second carrier frequency while receiving one or more NR SL packets.

4. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to cause the UE to:

in the case that the second carrier frequency is the same as the first carrier frequency, implement the frequency shift on the second carrier frequency while searching for a synchronization-reference (Sync-Ref) UE synchronized with a Radio Access Network (RAN) as an NR SL synchronization reference on the second carrier frequency.

5. The UE of claim 4 , wherein the RAN comprises one of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) or a New Radio-RAN (NR-RAN).

6. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to cause the UE to:

in the case that the second carrier frequency is the same as the first carrier frequency, implement the frequency shift on the second carrier frequency when the UE is configured to:

implement Global Navigation Satellite System (GNSS)-synchronization priority rules on the second carrier frequency, and

consider synchronization-reference (Sync-Ref) UEs directly synchronized with a Radio Access Network (RAN) as candidates of synchronization references for the NR SL communication.

7. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to cause the UE to:

in the case that the second carrier frequency is the same as the first carrier frequency, implement the frequency shift on the second carrier frequency when the UE is configured to:

implement Global Navigation Satellite System (GNSS)-synchronization priority rules on the second carrier frequency, and

consider synchronization-reference (Sync-Ref) UEs indirectly synchronized with a Radio Access Network (RAN) as candidates of synchronization references for the NR SL communication.

8. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to cause the UE to:

in the case that the second carrier frequency is the same as the first carrier frequency, implement the frequency shift on the second carrier frequency while transmitting an NR SL synchronization signal burst set as a synchronization-reference (Sync-Ref) UE on the second carrier frequency.

9. The UE of claim 1 , wherein the at least one processor is further configured to execute the computer-executable instructions to cause the UE to:

in the case that the second carrier frequency is the same as the first carrier frequency, implement the frequency shift on the second carrier frequency during an NR SL reception if the RAT-shared bit is set to true.

10. A method performed by a user equipment (UE), the method comprising:

receiving an indicator indicating that Long-Term-Evolution (LTE)-Vehicle to Everything (V2X) sidelink (SL) communication is shared with New Radio (NR) SL communication on at least a first carrier frequency in one or more carrier frequencies, the indicator including a radio access technology (RAT)-shared bit associated with the first carrier frequency in an NR SL frequency carrier configuration;

selecting a second carrier frequency in the one or more carrier frequencies for the NR SL communication; and

in a case that the second carrier frequency is the same as the first carrier frequency, implementing a frequency shift on the second carrier frequency while performing one or more NR SL transmissions.

11. The method of claim 10 , wherein the indicator is received through one of:

an SL pre-configuration;

an SL configuration received from a serving cell through a Uu interface; or

an SL configuration received from another UE via a PC5 air interface through Radio Resource Control (RRC) signaling.

12. The method of claim 10 , further comprising:

in the case that the second carrier frequency is the same as the first carrier frequency, implementing the frequency shift on the second carrier frequency while receiving one or more NR SL packets.

13. The method of claim 10 , further comprising:

in the case that the second carrier frequency is the same as the first carrier frequency, implementing the frequency shift on the second carrier frequency while searching for a synchronization-reference (Sync-Ref) UE synchronized with a Radio Access Network (RAN) as an NR SL synchronization reference on the second carrier frequency.

14. The method of claim 13 , wherein the RAN comprises one of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) or a New Radio-RAN (NR-RAN).

15. The method of claim 10 , further comprising:

in the case that the second carrier frequency is the same as the first carrier frequency, implementing the frequency shift on the second carrier frequency when the UE is configured to:

implement Global Navigation Satellite System (GNSS)-synchronization priority rules on the second carrier frequency, and

consider synchronization-reference (Sync-Ref) UEs directly synchronized with a Radio Access Network (RAN) as candidates of synchronization references for the NR SL communication.

16. The method of claim 10 , further comprising:

in the case that the second carrier frequency is the same as the first carrier frequency, implementing the frequency shift on the second carrier frequency when the UE is configured to:

implement Global Navigation Satellite System (GNSS)-synchronization priority rules on the second carrier frequency, and

consider synchronization-reference (Sync-Ref) UEs indirectly synchronized with a Radio Access Network (RAN) as candidates of synchronization references for the NR SL communication.

17. The method of claim 10 , further comprising:

in the case that the second carrier frequency is the same as the first carrier frequency, implementing the frequency shift on the second carrier frequency while transmitting an NR SL synchronization signal burst set as a synchronization-reference (Sync-Ref) UE on the second carrier frequency.

18. The method of claim 10 , further comprising:

in the case that the second carrier frequency is the same as the first carrier frequency, implementing the frequency shift on the second carrier frequency during an NR SL reception if the RAT-shared bit is set to true.