Sensing and resource selection based on priorities for sidelink transmissions

1. A method comprising:

sensing, by a first user equipment (UE), a signal from a second UE, the signal indicating a resource reservation for a shared channel for a second sidelink (SL) transmission by the second UE and a priority associated with the second SL transmission;

determining, by the first UE, a signal power threshold based on a reservation type of the second SL transmission and the priority, the reservation type being one of a plurality of reservation types, each reservation type of the plurality of reservation types corresponding to a different signal power threshold, the plurality of reservation types including at least two of:

a non-feedback-based SL retransmission,

a feedback-based SL retransmission,

an SL retransmission of a first transmission block (TB),

a new SL transmission of a second TB different from the first TB,

a long term resource reservation for future transmission of different one or more TBs,

a resource reservation for future transmission of a fixed number of future TBs, or

a resource reservation for an initial transmission of a TB using a standalone advanced control signal preceding initial transmission of the TB; and

selecting, by the first UE, a first resource in the shared channel to use for a first SL transmission by the first UE based on the signal power threshold.

2. The method of claim 1 , wherein the method further comprises:

measuring a signal power in the shared channel in respect of a second resource indicated in the resource reservation, and

wherein the selecting the first resource to use for the first SL transmission by the first UE comprises:

excluding the second resource indicated in the resource reservation if the signal power exceeds the signal power threshold.

3. The method of claim 1 , wherein the priority indicates a priority level of data for the second SL transmission by the second UE, and wherein the determining the signal power threshold comprises:

adjusting the priority associated with the second SL transmission by the second UE based on the reservation type of the second SL transmission indicated in the resource reservation to obtain an adjusted priority; and

selecting the signal power threshold by mapping the adjusted priority to a respective signal power threshold.

4. The method of claim 2 , wherein a set of candidate resources are predefined for the shared channel, and wherein the excluding the second resource indicated in the resource reservation comprises:

excluding the second resource from the set of candidate resources, and

wherein the selecting the first resource in the shared channel for the first SL transmission by the first UE comprises:

selecting the first resource from candidate resources remaining in the set of candidate resources.

5. The method of claim 4 , wherein the first resource includes a time/frequency resource.

6. The method of claim 1 , wherein the signal further indicates a resource reservation type that corresponds to the reservation type of the second SL transmission.

7. The method of claim 1 , wherein the shared channel is a shared data channel, and the signal is included in information received over a shared control channel; or

wherein the shared channel is a physical sidelink shared channel (PSSCH), and wherein the signal is a demodulation reference signal (DMRS).

8. The method of claim 1 , further comprising:

sending, by the first UE, a first signal indicating a first resource reservation for the first SL transmission by the first UE.

9. A first user equipment (UE) comprising:

a non-transitory memory storage comprising instructions;

a communication subsystem;

one or more processors in communication with the non-transitory memory storage and communication subsystem, wherein the one or more processors execute the instructions to cause the first UE to perform:

sensing, using the communication subsystem, a signal from a second UE, the signal indicating a resource reservation for a shared channel for a second sidelink (SL) transmission by the second UE and a priority associated with the second SL transmission;

determining a signal power threshold based on a reservation type of the second SL transmission and the priority, the reservation type being one of a plurality of reservation types, each reservation type of the plurality of reservation types corresponding to a different signal power threshold, the plurality of reservation types including at least two of:

a non-feedback-based SL retransmission,

a feedback-based SL retransmission,

an SL retransmission of a first transmission block (TB),

a new SL transmission of a second TB different from the first TB,

a long term resource reservation for future transmission of different one or more TBs,

a resource reservation for future transmission of a fixed number of future TBs, or

a resource reservation for an initial transmission of a TB using a standalone advanced control signal preceding initial transmission of the TB; and

selecting a first resource in the shared channel to use for a first SL transmission by the first UE based on the signal power threshold.

10. The first UE of claim 9 , wherein the first UE is further caused to perform:

measuring a signal power in the shared channel in respect of a second resource indicated in the resource reservation, and wherein the selecting the first resource to use for the first SL transmission by the first UE comprises:

excluding the second resource indicated in the resource reservation if the signal power exceeds the signal power threshold.

11. The first UE of claim 9 , wherein the priority indicates a priority level of data for the SL transmission by the second UE, and wherein the determining the signal power threshold comprises:

adjusting the priority associated with the second SL transmission by the second UE based on the reservation type of the second SL transmission indicated in the resource reservation to obtain an adjusted priority; and

selecting the signal power threshold by mapping the adjusted priority to a respective signal power threshold.

12. The first UE of claim 10 , wherein a set of candidate resources are predefined for the shared channel, and wherein the excluding the second resource indicated in the resource reservation comprises:

excluding the second resource from the set of candidate resources, and

wherein the selecting the first resource in the shared channel for the first SL transmission by the first UE comprises:

selecting the first resource from candidate resources remaining in the set of candidate resources.

13. The first UE of claim 12 , wherein the first resource includes a time/frequency resource.

14. The first UE of claim 9 , wherein the signal further indicates a resource reservation type that corresponds to the reservation type of the second SL transmission.

15. The first UE of claim 9 , wherein the shared channel is a shared data channel, and the signal is included in information received over a shared control channel; or

wherein the shared channel is a physical sidelink shared channel (PSSCH), and wherein the signal is a demodulation reference signal (DMRS).

16. The first UE of claim 9 , wherein the first UE is further caused to perform:

sending, using the communication subsystem, a first signal indicating a first resource reservation for the first SL transmission by the first UE.

17. The first UE of claim 9 wherein the first UE is further caused to perform:

sensing the signal from the second UE within a time-based sensing window.

18. A non-transitory computer readable medium having instructions stored thereon that, when executed by a first user equipment (UE), cause the first UE to perform operations, the operations comprising:

sensing, using a communication subsystem, a signal from a second UE, the signal indicating a resource reservation for a shared channel for a second sidelink (SL) transmission by the second UE and a priority associated with the second SL transmission;

determining a signal power threshold based on a reservation type of the second SL transmission and the priority, the reservation type being one of a plurality of reservation types, each reservation type of the plurality of reservation types corresponding to a different signal power threshold, the plurality of reservation types including at least two of:

a non-feedback-based SL retransmission,

a feedback-based SL retransmission,

an SL retransmission of a first transmission block (TB),

a new SL transmission of a second TB different from the first TB,

a long term resource reservation for future transmission of different one or more TBs,

a resource reservation for future transmission of a fixed number of future TBs, or

a resource reservation for an initial transmission of a TB using a standalone advanced control signal preceding initial transmission of the TB; and

selecting a first resource in the shared channel to use for a first SL transmission by the first UE based on the signal power threshold.