Dynamic switching of physical uplink control channel (PUCCH) between uplink (UL) and supplementary uplink (SUL)

1. A method of wireless communication performed by a user equipment (UE), the method comprising:

receiving, from base station, a first message indicating a selected carrier for transmission of an uplink (UL) message, the selected carrier comprising a UL carrier or a supplementary uplink (SUL) carrier, the UL carrier and the SUL carrier corresponding to a same logical cell index; and

transmitting the UL message to the base station via the selected carrier.

2. The method of claim 1 , further comprising receiving a configuration message from the base station, the configuration message indicating allocation of a first set of physical uplink control channel (PUCCH) resources corresponding to the UL carrier and allocation of a second set of PUCCH resources corresponding to the SUL carrier, wherein the first set of PUCCH resources comprise a first set of frequency resources and a first set of time resources corresponding to at least a portion of the UL carrier, and wherein the second set of PUCCH resources comprise a second set of frequency resources and a second set of time resources corresponding to at least a portion of the SUL carrier.

3. The method of claim 1 , wherein the UL message comprises a hybrid automatic repeat request acknowledgement (HARQ-ACK) message, wherein the first message comprises a downlink control information (DCI) message that indicates scheduling of a physical downlink shared channel (PDSCH), and wherein the HARQ-ACK message indicates acknowledgment of receipt of the PDSCH at the UE.

4. The method of claim 1 , further comprising:

receiving, from the base station, a second message indicating a second selected carrier for transmission of a second hybrid automatic repeat request acknowledgement (HARQ-ACK) message, wherein the UL message comprises a HARQ-ACK message and the first message comprises a downlink control information (DCI) message; and

receiving, from the base station, a third message indicating a third selected carrier for transmission of a third HARQ-ACK message.

5. The method of claim 4 , further comprising, based on a determination that one or more time resources allocated to physical uplink control channel (PUCCH) resources corresponding to the UL carrier overlap with one or more time resources allocated to PUCCH resources corresponding to the SUL carrier, transmitting a combined HARQ-ACK message to the base station via the third selected carrier.

6. The method of claim 4 , further comprising, based on a determination that one or more time resources allocated to physical uplink control channel (PUCCH) resources corresponding to the UL carrier overlap with one or more time resources allocated to PUCCH resources corresponding to the SUL carrier and a determination that the second selected carrier or the third selected carrier is the UL carrier, transmitting a combined HARQ-ACK message to the base station via the UL carrier.

7. The method of claim 4 , further comprising:

determining, from the second selected carrier and the third selected carrier, a carrier associated with a larger physical uplink control channel (PUCCH) resource allocation; and

based on a determination that one or more time resources allocated to PUCCH resources corresponding to the UL carrier overlap with one or more time resources allocated to PUCCH resources corresponding to the SUL carrier, transmitting a combined HARQ-ACK message to the base station via the carrier associated with the larger PUCCH resource allocation.

8. The method of claim 4 , further comprising:

measuring a power headroom associated with the UL carrier; and

based on a determination that one or more time resources allocated to physical uplink control channel (PUCCH) resources corresponding to the UL carrier overlap with one or more time resources allocated to PUCCH resources corresponding to the SUL carrier, a determination that the second selected carrier or the third selected carrier is the UL carrier, and a determination that the power headroom satisfies a threshold, transmitting a combined HARQ-ACK message to the base station via the UL carrier.

9. The method of claim 4 , further comprising:

measuring a channel quality associated with the second selected carrier;

measuring a channel quality associated with the third selected carrier;

determining a preferred carrier from the second selected carrier and the third selected carrier based on the measured channel qualities; and

based on a determination that one or more time resources allocated to physical uplink control channel (PUCCH) resources corresponding to the UL carrier overlap with one or more time resources allocated to PUCCH resources corresponding to the SUL carrier, transmitting a combined HARQ-ACK message to the base station via the preferred carrier.

10. The method of claim 1 , further comprising:

scheduling asynchronous transmission of the UL message on the UL carrier or on the SUL carrier.

11. An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured to:

receive, at a user equipment (UE) from base station, a first message indicating a selected carrier for transmission of an uplink (UL) message, the selected carrier comprising a UL carrier or a supplementary uplink (SUL) carrier, the UL carrier and the SUL carrier corresponding to a same logical cell index; and

initiate transmission of the UL message to the base station via the selected carrier.

12. The apparatus of claim 11 , wherein the UL carrier corresponds to a first set of frequency resources, and wherein the SUL carrier corresponds to a second set of frequency resources.

13. The apparatus of claim 12 , wherein the second set of frequency resources occupies lower bandwidths than the first set of frequency resources.

14. The apparatus of claim 11 , wherein the UL message comprises a semi-persistent channel state information (SP-CSI) message, and wherein the first message comprises a medium access control (MAC) control element (MAC-CE) indicating activation of a SP-CSI resource at the UE.

15. The apparatus of claim 14 , wherein the at least one processor is further configured to:

after initiating transmission of the SP-CSI message, receive, from the base station, a second MAC-CE indicating a second selected carrier for SP-CSI transmission; and

initiate transmission of a second SP-CSI message to the base station via the second selected carrier.

16. A method of wireless communication, the method comprising:

selecting, at a base station, a carrier from a group of carriers that includes an uplink (UL) carrier and a supplementary uplink (SUL) carrier, the UL carrier and the SUL carrier corresponding to a same logical cell index;

transmitting, to a user equipment (UE), a first message that indicates the selected carrier is for transmission of a UL message; and

receiving the UL message from the UE via the selected carrier.

17. The method of claim 16 , further comprising:

measuring a power headroom associated with the UL carrier; and

selecting the UL carrier as the selected carrier based on the power headroom satisfying a threshold.

18. The method of claim 17 , further comprising selecting the SUL carrier as the selected carrier based on the power headroom failing to satisfy the threshold.

19. The method of claim 16 , further comprising:

receiving a first channel state information (CSI) message associated with the UL carrier from the UE;

receiving a second CSI message associated with the SUL carrier from the UE;

determining a carrier associated with a higher channel quality from the UL carrier and the SUL carrier based on the first CSI message and the second CSI message; and

selecting the carrier associated with the higher channel quality as the selected carrier.

20. The method of claim 16 , further comprising:

receiving a first sounding reference signal (SRS) from the UE via the UL carrier;

receiving a second SRS from the UE via the SUL carrier;

determining a carrier associated with a higher channel quality from the UL carrier and the SUL carrier based on the first SRS and the second SRS; and

selecting the carrier associated with the higher channel quality as the selected carrier.

21. The method of claim 16 , further comprising transmitting a configuration message to the UE, the configuration message indicating allocation of a first set of physical uplink control channel (PUCCH) resources corresponding to the UL carrier and allocation of a second set of PUCCH resources corresponding to the SUL carrier, wherein the first set of PUCCH resources comprise a first set of frequency resources and a first set of time resources corresponding to at least a portion of the UL carrier, and wherein the second set of PUCCH resources comprise a second set of frequency resources and a second set of time resources corresponding to at least a portion of the SUL carrier.

22. The method of claim 16 , wherein the UL message comprises a hybrid automatic repeat request acknowledgement (HARQ-ACK) message, wherein the first message comprises a downlink control information (DCI) message that indicates scheduling of a physical downlink shared channel (PDSCH), and wherein the HARQ-ACK message indicates acknowledgment of receipt of the PDSCH at the UE.

23. The method of claim 16 , further comprising:

transmitting, to the UE, a second message indicating a second selected carrier for transmission of a second hybrid automatic repeat request acknowledgement (HARQ-ACK) message, wherein the UL message comprises a HARQ-ACK message and the first message comprises a downlink control information (DCI) message; and

transmitting, to the UE, a third message indicating a third selected carrier for transmission of a third HARQ-ACK message, wherein one or more time resources allocated to physical uplink control channel (PUCCH) resources corresponding to the UL carrier overlap with one or more time resources allocated to PUCCH resources corresponding to the SUL carrier.

24. The method of claim 23 , further comprising:

monitoring the third selected carrier according to PUCCH resources allocated to the third selected carrier; and

receiving a combined HARQ-ACK message from the UE via the third selected carrier.

25. The method of claim 23 , further comprising:

monitoring the UL carrier according to PUCCH resources allocated to the UL carrier based on a determination that the second selected carrier or the third selected carrier is the UL carrier; and

receiving a combined HARQ-ACK message from the UE via the UL carrier.

26. The method of claim 23 , further comprising:

determining, from the second selected carrier and the third selected carrier, a carrier associated with a larger PUCCH resource allocation;

monitoring the carrier associated with the larger PUCCH resource allocation after according to the PUCCH resources allocated to the carrier associated with the larger PUCCH allocation; and

receiving a combined HARQ-ACK message from the UE via the carrier associated with the larger PUCCH allocation.

27. An apparatus configured for wireless communication, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured to:

select, at a base station, a carrier from a group of carriers that includes an uplink (UL) carrier and a supplementary uplink (SUL) carrier, the UL carrier and the SUL carrier corresponding to a same logical cell index;

initiate transmission, to a user equipment (UE), of a first message that indicates the selected carrier is for transmission of a UL message; and

receive the UL message from the UE via the selected carrier.

28. The apparatus of claim 27 , wherein the UL carrier corresponds to a first set of frequency resources, and wherein the SUL carrier corresponds to a second set of frequency resources, and wherein the second set of frequency resources occupies lower bandwidths than the first set of frequency resources.

29. The apparatus of claim 27 , wherein the UL message comprises a semi-persistent channel state information (SP-CSI) message, and wherein the first message comprises a medium access control (MAC) control element (MAC-CE) indicating activation of a SP-CSI resource at the UE.

30. The apparatus of claim 29 , wherein the at least one processor is further configured to:

after receiving the SP-CSI message, initiate transmission, to the UE, of a second MAC-CE indicating a second selected carrier for SP-CSI transmission; and

receive a second SP-CSI message from the UE via the second selected carrier.