Resource selection for sidelink
Sidelink (SL) resource selection includes determining that all SL resources within an SL resource pool for an SL resource selection window are unclaimed for SL transmission when no prior sensing results are available for an SL channel, and determining which SL resources within the SL resource pool are unclaimed for SL transmission based on the prior sensing results when prior sensing results are available. Unclaimed SL resource(s) are randomly selected, and the SL channel is sensed during one or more slots preceding the randomly selected SL resource(s) to determine availability before transmitting on or signaling the randomly selected SL resource(s). Transmission on a first-in-time of the randomly selected SL resource(s) is based on the availability determination and, in the first-in-time randomly selected SL resource, one or more additional SL resource(s) are signaled based on the availability determination.
1. An apparatus, comprising:
a processor configured to:
determine, based on a prior partial sensing result, candidate sidelink (SL) resources within a SL resource pool and a SL resource selection window,
randomly select one or more of the candidate SL resources, and
before transmitting on or signaling the one or more randomly selected SL resources:
sense a SL channel during one or more slots preceding the one or more randomly selected SL resources, and
determine availability of the one or more randomly selected SL resources based on results of the sensing; and
a transceiver operably coupled to the processor and configured to transmit on a first-in-time of the one or more randomly selected SL resources based on the determination of availability of the one or more randomly selected SL resources.
2. The apparatus of claim 1 , wherein the processor is configured to signal, in the first-in-time of the one or more randomly selected SL resource, one or more additional SL resources based on the determination of availability of the one or more randomly selected SL resources.
3. The apparatus of claim 1 , wherein transmission on or signaling of an SL resource is on the one or more randomly selected SL resources when the determination of the availability of the one or more randomly selected SL resources is that the one or more randomly selected SL resources are available, and
wherein there is no transmission on or no signaling of a SL resource when the determination of the availability of the randomly selected SL resource is that the randomly selected SL resource is one of:
reserved for another SL transmission, or
preempted for another SL transmission.
4. The apparatus of claim 3 , wherein the processor is configured to check for preemption of the one or more randomly selected SL resources that have been signaled in a prior slot.
5. The apparatus of claim 1 , wherein, when an SL resource among the randomly selected SL resources is determined to be reserved for another transmission or preempted for another SL transmission,
another available SL resource is selected from the remaining one or more randomly selected SL resources.
6. The apparatus of claim 1 , wherein the randomly selected SL resources satisfy time restrictions including one or more of:
that a time separation between two consecutive SL resources of the randomly selected SL resources is not less than a minimum value, or
that a time separation between the two consecutive SL resources of the randomly selected SL resources is not more than a maximum value.
7. The apparatus of claim 1 , wherein:
to determine availability of a randomly selected SL resource, the processor is further configured to perform contiguous sensing starting M logical slots earlier than a slot of the randomly selected SL resource, and
M is 31.
8. The apparatus of claim 1 , wherein:
to determine availability of a randomly selected SL resource, the processor is further configured to perform contiguous sensing starting M logical slots earlier than a slot of the randomly selected SL resource, and
M is a configured value.
9. The apparatus of claim 1 , wherein to determine availability of a randomly selected SL resource, the processor is further configured to perform contiguous sensing starting no earlier than a resource selection trigger slot.
10. The apparatus of claim 1 , wherein:
to determine availability of a randomly selected SL resource, the processor is further configured to perform contiguous sensing ending T logical slots earlier than a slot of the randomly selected SL resource, and
T equals sum of sensing processing time and resource selection processing time.
11. A method, comprising:
determining, based on a prior partial sensing result, candidate sidelink (SL) resources within a SL resource pool and a SL resource selection window;
randomly selecting one or more of the candidate SL resources;
before transmitting on or signaling the one or more randomly selected SL resources:
sensing a SL channel during one or more slots preceding the one or more randomly selected SL resources, and
determining availability of the one or more randomly selected SL resources based on results of the sensing; and
transmitting on a first-in-time of the one or more randomly selected SL resources based on the determination of availability of the one or more randomly selected SL resources.
12. The method of claim 11 , further comprising signaling, in the first-in-time of the one or more randomly selected SL resource, one or more additional SL resources based on the determination of availability of the one or more randomly selected SL resources.
13. The method of claim 11 , wherein transmission on or signaling of an SL resource is on the one or more randomly selected SL resources when the determination of the availability of the one or more randomly selected SL resources is that the one or more randomly selected SL resources are available, and
wherein there is no transmission on or no signaling of a SL resource when the determination of the availability of the randomly selected SL resource is that the randomly selected SL resource is one of:
reserved for another SL transmission, or
preempted for another SL transmission.
14. The method of claim 13 , further comprising checking for preemption of the one or more randomly selected SL resources that have been signaled in a prior slot.
15. The method of claim 11 , wherein, when an SL resource among the randomly selected SL resources is determined to be reserved for another transmission or preempted for another SL transmission,
another available SL resource is selected from the remaining one or more randomly selected SL resources.
16. The method of claim 11 , wherein the randomly selected SL resources satisfy time restrictions including one or more of:
that a time separation between two consecutive SL resources of the randomly selected SL resources is not less than a minimum value, or
that a time separation between the two consecutive SL resources of the randomly selected SL resources is not more than a maximum value.
17. The method of claim 11 , wherein:
to determine availability of a randomly selected SL resource, the method further comprises performing contiguous sensing starting M logical slots earlier than a slot of the randomly selected SL resource, and
M is 31.
18. The method of claim 11 , wherein:
to determine availability of a randomly selected SL resource, the method further comprises performing contiguous sensing starting M logical slots earlier than a slot of the randomly selected SL resource, and
M is a configured value.
19. The method of claim 11 , wherein:
to determine availability of a randomly selected SL resource, the method further comprises performing contiguous sensing starting no earlier than a resource selection trigger slot.
20. The method of claim 11 , wherein:
to determine availability of a randomly selected SL resource, the method further comprises performing contiguous sensing ending T logical slots earlier than a slot of the randomly selected SL resource, and
T equals sum of sensing processing time and resource selection processing time.