Transmission of channel occupancy time-sharing information (COT-SI) reserving a COT for sidelink communications in unlicensed bands

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

performing a channel access procedure to acquire a current channel occupancy time (COT) and one or more future COTs in a sidelink channel over an unlicensed new radio (NR) band, wherein a number of the acquired COTs equals a difference between a maximum number of physical sidelink shared channel (PSSCH) reservations a first stage sidelink control information (SCI-1) is configured to reserve and a number of one or more PSSCH reservations that the SCI-1 is configured to reserve;

transmitting, via the SCI-1, COT sharing information (COT-SI) indicating a structure of the current COT; and

transmitting a plurality of physical sidelink shared channel (PSSCH) reservations, with a first subset of the plurality of PSSCH reservations in the current COT and a second subset of the plurality of PSSCH reservations in the one or more future COTs.

2. The method of claim 1 , wherein the COT-SI is transmitted via the SCI-1 carried by a physical sidelink control channel (PSCCH) transmission.

3. The method of claim 2 , wherein the SCI-1 includes a field having bit values configured to encode the COT-SI.

4. The method of claim 1 , wherein the COT-SI is transmitted via second stage sidelink control information (SCI-2) carried by a physical sidelink shared channel (PSSCH) transmission.

5. The method of claim 1 , wherein the sidelink channel includes:

(a) a first subchannel having: (i) a first resource configured for a PSCCH transmission carrying the SCI-1, and (ii) a second resource configured for a first portion of a multi-channel PSSCH transmission, and

(b) a second subchannel having: (i) a third resource configured for the transmitting the COT-SI, and (ii) a fourth resource configured for a second portion of the multi-channel PSSCH transmission,

wherein the SCI-1 is configured to reserve the second resource in the first subchannel and the fourth resource in the second subchannel.

6. The method of claim 5 , wherein the SCI-1 is configured to include information about the transmitting the COT-SI.

7. The method of claim 6 , wherein the information includes an indication of at least one of a presence of the COT-SI at the third resource, or a location of the third resource in the sidelink channel.

8. The method of claim 5 , wherein the COT-SI is configured to use a SCI-1 waveform.

9. The method of claim 5 , wherein the first subchannel includes a fifth resource configured for transmitting second stage sidelink control information (SCI-2) without rate-matching the SCI-2 to the third resource.

10. The method of claim 1 , wherein:

the sidelink channel includes a first subchannel having a first resource configured for transmitting a PSCCH transmission carrying the SCI-1, the SCI-1 configured to reserve a second resource for a single-channel PSSCH transmission in the first subchannel; and

the COT-SI is transmitted via a third resource in a second subchannel of the sidelink channel that is different from the first subchannel.

11. The method of claim 10 , wherein the COT-SI is configured to have a same payload size as the SCI-1.

12. The method of claim 10 , wherein the first subchannel includes a fifth resource configured for transmitting second stage sidelink control information (SCI-2) configured to reserve the third resource in the second subchannel.

13. The method of claim 12 , wherein at least one of the SCI-1 or the SCI-2 include SCI signaling about the COT-SI configured to assist a second UE receiving the COT-SI with decoding the COT-SI.

14. The method of claim 13 , wherein the SCI signaling includes at least one of information about a waveform of the COT-SI, a payload size of the COT-SI, or a field contained within the COT-SI related to the acquired COTs.

15. The method of claim 14 , wherein at least one of:

the waveform of the COT-SI is different from a waveform of the SCI-1; or

the payload of the COT SI is different from a payload of the SCI-1.

16. The method of claim 1 , wherein the COT-SI is transmitted via a dedicated physical sidelink channel of the sidelink channel that is configured to carry only COT-SI signals.

17. The method of claim 16 , wherein the dedicated physical sidelink channel is located within a physical sidelink shared channel (PSSCH) of the sidelink channel, the location being at a last defined number symbols of the PSSCH, at a fixed location within the PSSCH, at any location within the PSSCH after a SCI-2 transmission is completed, or a combination thereof.

18. The method of claim 1 , further comprising transmitting at least one of the SCI-1 or second stage sidelink control information (SCI-2) indicating a resource of the sidelink channel that is configured to transmit the COT-SI.

19. The method of claim 1 , wherein the COT-SI is transmitted via a gap symbol or an automatic gain control (AGC) symbol of the sidelink channel.

20. The method of claim 19 , wherein the sidelink channel includes a subchannel having the gap symbol, the AGC symbol, a first resource configured for transmitting the SCI-1, and a second resource configured for transmitting second stage sidelink control information (SCI-2),

wherein at least one of the SCI-1 or the SCI-2 includes an indication that the COT-SI is transmitted via the gap symbol or the AGC symbol.

21. A user equipment (UE), comprising:

a memory;

a transceiver; and

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

perform a channel access procedure to acquire a current channel occupancy time (COT) and one or more future COTs in a sidelink channel over an unlicensed new radio (NR) band, wherein a number of the acquired COTs equals a difference between a maximum number of physical sidelink shared channel (PSSCH) reservations first stage sidelink control information (SCI-1) is configured to reserve and a number of one or more PSSCH reservations that the SCI-1 is configured to reserve;

transmit, via the SCI-1, COT sharing information (COT-SI) indicating a structure of the current COT; and

transmit a plurality of PSSCH reservations, with a first subset of the plurality of PSSCH reservations in the current COT and a second subset of the plurality of PSSCH reservations in the one or more future COTs.

22. The UE of claim 21 , wherein the COT-SI is transmitted via at least one of the SCI-1 carried by a physical sidelink control channel (PSCCH) transmission or second stage sidelink control information (SCI-2) carried by a physical sidelink shared channel (PSSCH) transmission.

23. The UE of claim 21 , wherein the sidelink channel includes:

(a) a first subchannel having: (i) a first resource configured for a PSCCH transmission carrying the SCI-1, and (ii) a second resource configured for a first portion of a multi-channel PSSCH transmission, and

(b) a second subchannel having: (i) a third resource configured for the transmitting the COT-SI, and (ii) a fourth resource configured for a second portion of the multi-channel PSSCH transmission,

wherein the SCI-1 is configured to reserve the second resource in the first subchannel and the fourth resource in the second subchannel.

24. The UE of claim 21 , wherein:

the sidelink channel includes a first subchannel having a first resource configured for transmitting a PSCCH transmission carrying the SCI-1, the SCI-1 configured to reserve a second resource for a single-channel PSSCH transmission in the first subchannel; and

the COT-SI is transmitted via a third resource in a second subchannel of the sidelink channel that is different from the first subchannel.

25. The UE of claim 21 , wherein the COT-SI is transmitted via a dedicated physical sidelink channel of the sidelink channel that is configured to carry only COT-SI signals.

26. The UE of claim 21 , wherein the UE is further configured to transmit at least one of the SCI-1 and/or second stage sidelink control information (SCI-2) indicating a resource of the sidelink channel that is configured to transmit the COT-SI.

27. The UE of claim 21 , wherein the COT-SI is transmitted via a gap symbol or an automatic gain control (AGC) symbol of the sidelink channel.

28. A non-transitory computer-readable medium (CRM) having program code recorded thereon, the program code comprising:

code for causing a user equipment (UE) to perform a channel access procedure to acquire a current channel occupancy time (COT) and one or more future COTs in a sidelink channel over an unlicensed new radio (NR) band, wherein a number of the acquired COTs equals a difference between a maximum number of physical sidelink shared channel (PSSCH) reservations a first stage sidelink control information (SCI-1) is configured to reserve and a number of one or more PSSCH reservations that the SCI-1 is configured to reserve;

code for causing the UE to transmit, via the SCI-1, COT sharing information (COT-SI) indicating a structure of the current COT; and

code for causing the UE to transmit a plurality of PSSCH reservations, with a first subset of the plurality of PSSCH reservations in the current COT and a second subset of the plurality of PSSCH reservations in the one or more future COTs.

29. A user equipment (UE), comprising:

means for performing a channel access procedure to a current channel occupancy time (COT) and one or more future COTs in a sidelink channel over an unlicensed new radio (NR) band, wherein a number of the acquired COTs equals a difference between a maximum number of physical sidelink shared channel (PSSCH) reservations a first stage sidelink control information (SCI-1) is configured to reserve and a number of one or more PSSCH reservations that the SCI-1 is configured to reserve;

means for transmitting, via the SCI-1, COT sharing information (COT-SI) indicating a structure of the current COT; and

means for transmitting a plurality of PSSCH reservations, with a first subset of the plurality of PSSCH reservations in the current COT and a second subset of the plurality of PSSCH reservations in the one or more future COTs.