Multiplexing physical sidelink feedback channels in sidelink communication

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

receiving, from a second sidelink UE, a configuration indicating a physical sidelink feedback channel (PSFCH) resource pool associated with multiplexing a first PSFCH having a first format with a second PSFCH having a second format, wherein the second format is different from the first format;

receiving, from the second sidelink UE, one or more transport blocks (TBs) via a groupcast message with a groupcast ID;

selecting, from the resource pool based on a hashing function of an addition of the groupcast ID with an identifier associated with the second sidelink UE, first resources associated with the first PSFCH; and

transmitting, to the second sidelink UE based on the configuration, an acknowledgement/negative-acknowledgment (ACK/NACK) associated with the one or more TBs via the first PSFCH using the first resources and a second ACK/NACK via the second PSFCH multiplexed with the first PSFCH.

2. The method of claim 1 , wherein:

the first format is a PSFCH format 0; and

the second format is a PSFCH format 2.

3. The method of claim 1 , wherein the transmitting the ACK/NACK comprises at least one of:

transmitting the ACK/NACK via the first PSFCH multiplexed in a time domain with the second PSFCH; or

transmitting the ACK/NACK via the first PSFCH multiplexed in a frequency domain with the second PSFCH.

4. The method of claim 1 , wherein the transmitting the ACK/NACK comprises:

transmitting the ACK/NACK via the first PSFCH using a first frequency interlace; and

transmitting the ACK/NACK via the second PSFCH using a second frequency interlace, wherein the second frequency interlace is different from the first frequency interlace.

5. The method of claim 1 , wherein the configuration indicates a PSFCH periodicity; and

the transmitting the ACK/NACK comprises:

transmitting the ACK/NACK via the first PSFCH based on the PSFCH periodicity; and

transmitting the ACK/NACK via the second PSFCH based on the PSFCH periodicity offset in time from the first PSFCH.

6. The method of claim 1 , wherein:

the second format is a PSFCH format 2; and

the transmitting the ACK/NACK further comprises applying an orthogonal cover code to the second PSFCH.

7. The method of claim 1 , wherein the receiving the configuration comprises receiving the configuration via a radio resource control message.

8. The method of claim 1 , wherein the configuration indicates a resource pool associated with the first PSFCH and the second PSFCH; and further comprising:

receiving, from the second sidelink UE, sidelink control information (SCI) indicating:

first resources of the resource pool associated with the first PSFCH; and

second resources of the resource pool associated with the second PSFCH.

9. The method of claim 1 , further comprising:

selecting, from the resource pool based on a hashing function of at least one of a groupcast identifier or an identifier associated with the second sidelink UE,

second resources associated with the second PSFCH.

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

transmitting, to a second sidelink UE, a configuration indicating a physical sidelink feedback channel (PSFCH) resource pool associated with multiplexing a first PSFCH having a first format with a second PSFCH having a second format, wherein the second format is different from the first format;

transmitting, to the second sidelink UE, one or more transport blocks (TBs) via a groupcast message with a groupcast ID; and

receiving, from the second sidelink UE, an acknowledgement/negative-acknowledgment (ACK/NACK) associated with the one or more TBs via the first PSFCH via first resources and a second ACK/NACK via the second PSFCH multiplexed with the first PSFCH,

wherein the first resources are selected from the resource pool based on a hashing function of an addition of the groupcast ID with an identifier associated with the first sidelink UE.

11. The method of claim 10 , wherein:

the first format is a PSFCH format 0; and

the second format is a PSFCH format 2.

12. The method of claim 10 , wherein the receiving the ACK/NACK comprises at least one of:

receiving the ACK/NACK via the first PSFCH multiplexed in a time domain with the second PSFCH; or

receiving the ACK/NACK via the first PSFCH multiplexed in a frequency domain with the second PSFCH.

13. The method of claim 10 , wherein the receiving the ACK/NACK comprises:

receiving the ACK/NACK via the first PSFCH using a first frequency interlace; and

receiving the ACK/NACK via the second PSFCH using a second frequency interlace, wherein the second frequency interlace is different from the first frequency interlace.

14. The method of claim 10 , wherein the configuration indicates a PSFCH periodicity; and

the receiving the ACK/NACK comprises:

receiving the ACK/NACK via the first PSFCH based on the PSFCH periodicity; and

receiving the ACK/NACK via the second PSFCH based on the PSFCH periodicity offset in time from the first PSFCH.

15. The method of claim 10 , wherein:

the second format is a PSFCH format 2; and

the receiving the ACK/NACK comprises receiving the second PSFCH coded via an orthogonal cover code.

16. A first sidelink user equipment (UE) comprising:

a memory;

a transceiver; and

at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to:

receive, from a second sidelink UE, a configuration indicating a physical sidelink feedback channel (PSFCH) resource pool associated with multiplexing a PSFCH having a first format with a second PSFCH having a second format, wherein the second format is different from the first format;

receive, from the second sidelink UE, one or more transport blocks (TBs) via a groupcast message with a groupcast ID;

selecting, from the resource pool based on a hashing function of an addition of the groupcast ID with an identifier associated with the second sidelink UE, first resources associated with the first PSFCH; and

transmit, to the second sidelink UE based on the configuration, an acknowledgement/negative-acknowledgment (ACK/NACK) associated with the one or more TBs via the first PSFCH using the first resources and a second ACK/NACK via the second PSFCH multiplexed with the first PSFCH.

17. The first sidelink UE of claim 16 , wherein:

the first format is a PSFCH format 0; and

the second format is a PSFCH format 2.

18. The first sidelink UE of claim 16 , wherein the first sidelink UE is further configured to at least one of:

transmit the ACK/NACK via the first PSFCH multiplexed in a time domain with the second PSFCH; or

transmit the ACK/NACK via the first PSFCH multiplexed in a frequency domain with the second PSFCH.

19. The first sidelink UE of claim 16 , wherein the first sidelink UE is further configured to at least one of:

transmit the ACK/NACK via the first PSFCH using a first frequency interlace; and

transmit the ACK/NACK via the second PSFCH using a second frequency interlace, wherein the second frequency interlace is different from the first frequency interlace.

20. The first sidelink UE of claim 16 , wherein the configuration indicates a PSFCH periodicity; and

the first sidelink UE is further configured to:

transmit the ACK/NACK via the first PSFCH based on the PSFCH periodicity; and

transmit the ACK/NACK via the second PSFCH based on the PSFCH periodicity offset in time from the first PSFCH.

21. The first sidelink UE of claim 16 , wherein the second format is a PSFCH format 2; and

the first sidelink UE is further configured to:

apply an orthogonal cover code to the second PSFCH.

22. The first sidelink UE of claim 16 , wherein the first sidelink UE is further configured to receive the configuration via a radio resource control message.

23. The first sidelink UE of claim 16 , wherein the configuration indicates a resource pool associated with the first PSFCH and the second PSFCH; and

the first sidelink UE is further configured to:

receive, from the second sidelink UE, sidelink control information (SCI) indicating:

first resources of the resource pool associated with the first PSFCH; and

second resources of the resource pool associated with the second PSFCH.

24. The first sidelink UE of claim 16 , wherein

the first sidelink UE is further configured to:

select, from the resource pool based on a hashing function of at least one of a groupcast identifier or an identifier associated with the second sidelink UE,

second resources associated with the second PSFCH.

25. A first sidelink user equipment (UE) comprising:

a memory;

a transceiver; and

at least one processor coupled to the memory and the transceiver, wherein the first sidelink UE is configured to:

transmit, to a second sidelink UE, a configuration indicating a physical sidelink feedback channel (PSFCH) resource pool associated with multiplexing a first PSFCH having a first format with a second PSFCH having a second format, wherein the second format is different from the first format;

transmit, to the second sidelink UE, one or more transport blocks (TBs) via a groupcast message with a groupcast ID; and

receive, from the second sidelink UE, an acknowledgement/negative-acknowledgment (ACK/NACK) associated with the one or more TBs via the first PSFCH via first resources and a second ACK/NACK via the second PSFCH multiplexed with the first PSFCH,

wherein the first resources are selected from the resource pool based on a hashing function of an addition of the groupcast ID with an identifier associated with the first sidelink UE.

26. The first sidelink UE of claim 25 , wherein:

the first format is a PSFCH format 0; and

the second format is a PSFCH format 2.

27. The first sidelink UE of claim 25 , wherein the first sidelink UE is further configured to at least one of:

receive the ACK/NACK via the first PSFCH multiplexed in a time domain with the second PSFCH; or

receive the ACK/NACK via the first PSFCH multiplexed in a frequency domain with the second PSFCH.

28. The first sidelink UE of claim 25 , wherein the first sidelink UE is further configured to:

receive the ACK/NACK via the first PSFCH using a first frequency interlace; and

receive the ACK/NACK via the second PSFCH using a second frequency interlace, wherein the second frequency interlace is different from the first frequency interlace.

29. The first sidelink UE of claim 25 , wherein the configuration indicates a PSFCH periodicity; and

the first sidelink UE is further configured to:

receive the ACK/NACK via the first PSFCH based on the PSFCH periodicity; and

receive the ACK/NACK via the second PSFCH based on the PSFCH periodicity offset in time from the first PSFCH.

30. The first sidelink UE of claim 25 , wherein:

the second format is a PSFCH format 2; and

the first sidelink UE is further configured to receive the second PSFCH coded via an orthogonal cover code.