Method and apparatus for low power sensing for sidelink in wireless communication systems

1. A user equipment (UE), comprising:

a transceiver configured to transmit, on a sidelink (SL) interface, traffic with a periodicity; and

a processor operably coupled to the transceiver, the processor configured to:

operate in a transmit (TX) resource pool with a parameter sl-MultiReserveResource set to enabled;

perform at least partial sensing including to:

determine a resource selection window,

select Y slots {t′ y SL } within the resource selection window, wherein y=0 . . . Y−1, and

for each slot t′ y SL , sense a set of slots, {t′ y-K i ×T′ i SL }, wherein:

T′ i is a periodicity of sensing from a set of sensing periodicities {T′ƒ 1 , T′ 2 , . . . , T′ I },

I is a number of sensing periodicities and I≥1, and

K i is a set of periodic sensing occasions that are sensed {k i,0 , k i,1 , . . . } and is associated with a sensing periodicity T′ i , and

determine candidate resources available in the resource selection window after resource exclusion based on the at least partial sensing, and

perform resource selection within the available candidate resources.

2. The UE of claim 1 wherein:

the TX resource pool is configured with one or more resource reservation periods, P reserve , provided by a parameter sl-ResourceReservationPeriodList, and

the I sensing periodicities are selected from among the configured P reserve resource reservation periods of the TX resource pool.

3. The UE of claim 1 wherein the set of periodic sensing occasions that are sensed is the same across the set of sensing periodicities, K 1 =K 2 = . . . =K 1 =K, K={k 0 , k 1 , . . . }.

4. The UE of claim 1 , wherein one of the set of sensing periodicities is a periodicity of the SL traffic.

5. The UE of claim 1 , wherein the processor is further configured to:

trigger SL resource selection in a slot n,

determine an earliest sensing time, T sense , and

sense no earlier than T sense before the slot n.

6. The UE of claim 1 , wherein:

an earliest of the Y selected slots is t′ y0 SL ,

the processor is further configured to determine the candidate resources in a slot n, and

the slot n is a resource selection processing time, t proc,1 SL , before t′ y0 SL .

7. The UE of claim 1 , wherein:

the processor is further configured to determine the candidate resources in a slot n, and

a latest periodic sensing occasion is earlier than a sensing processing latency time, t proc,0 SL , before the slot n.

8. The UE of claim 1 , wherein the number of sensing periodicities I used for sensing is based on a channel busy ratio (CBR).

9. The UE of claim 1 , wherein:

the TX resource pool is further configured with at least random resource selection and is configured with a priority threshold,

for SL traffic with priority values less than or equal to the priority threshold, random resource selection and other sensing methods are allowed, and

otherwise, only the other sensing methods are allowed.

10. The UE of claim 1 , wherein:

the TX resource pool is configured with a set of SL resources and a priority threshold,

within the set of configured SL resources, for SL traffic with priority values less than or equal to the priority threshold, at least random resource selection is allowed, and

outside the set of configured SL resources, for SL traffic with priority values greater than the priority threshold, at least random resource selection is allowed.

11. A method of operating a user equipment (UE), the method comprising:

transmitting, on a sidelink (SL) interface, traffic with a periodicity;

operating in a transmit (TX) resource pool with a parameter sl-MultiReserveResource set to enabled;

performing at least partial sensing including:

determining a resource selection window,

selecting Y slots {t′ y SL } within the resource selection window, wherein y=0 . . . Y−1, and

for each slot t′ y SL , sensing a set of slots, {t′ y-K i ×T′ i SL }, wherein;

T′ i is a periodicity of sensing from a set of sensing periodicities {T′ 1 , T′ 2 , . . . T′ I },

I is a number of sending periodicities and I≥1, and

K i is a set of periodic sensing occasions that are sensed {k i,0 , k i,1 , . . . } and is associated with a sensing periodicity T′ i ;

determining candidate resources available in the resource selection window after resource exclusion based on the at least partial sensing; and

performing resource selection within the available candidate resources.

12. The method of claim 11 wherein,

the TX resource pool is configured with one or more resource reservation periods, P reserve , provided by a parameter sl-ResourceReservationPeriodList, and

the I sensing periodicities are selected from among the configured P reserve resource reservation periods of the TX resource pool.

13. The method of claim 11 wherein the set of periodic sensing occasions that are sensed is the same across the set of sensing periodicities, K 1 =K 2 = . . . =K 1 =K, K={k 0 , k 1 , . . . }.

14. The method of claim 11 , wherein one of the set of sensing periodicities is a periodicity of the SL traffic.

15. The method of claim 11 , further comprising:

triggering SL resource selection in a slot n,

determining an earliest sensing time, T sense , and

sensing no earlier than T sense before the slot n.

16. The method of claim 11 , wherein:

an earliest of the Y selected slots is t′ y0 SL ,

the method further comprises determining the candidate resources in a slot n, and

the slot n is a resource selection processing time, t proc,1 SL , before t′ y0 SL .

17. The method of claim 11 , further comprising:

determining the candidate resources in a slot n,

wherein a latest periodic sensing occasion is a sensing processing latency time, t proc,0 SL , before the slot n.

18. The method of claim 11 , wherein the number of sensing periodicities I used for sensing is based on a channel busy ratio (CBR).

19. The method of claim 11 , wherein:

the TX resource pool is further configured with at least random resource selection and is configured with a priority threshold,

for SL traffic with priority values less than or equal to the priority threshold, random resource selection and other sensing methods are allowed, and

otherwise, only the other sensing methods are allowed.

20. The method of claim 11 , wherein:

the TX resource pool is configured with a set of SL resources and a priority threshold,

within the set of configured SL resources, for SL traffic with priority values less than or equal to the priority threshold, at least random resource selection is allowed, and

outside the set of configured SL resources, for SL traffic with priority values greater than the priority threshold, at least random resource selection is allowed.