Distributed sidelink resource allocation
Methods, systems, and devices for wireless communications are described. Generally, the described techniques provide for determining shared resources associated with one or more user equipments (UEs) for sidelink communications, including control resources and data resources. A first UE may transmit a sidelink request to reserve a subset of data resources to a second UE, and may monitor for one or more sidelink responses indicating a positive sidelink response to the sidelink request, a negative sidelink response to the sidelink request, or both. The second UE may transmit a positive sidelink response if it is available for a data transmission. A third UE may transmit a negative sidelink response if it objects to the data transmission. The first UE may determine, based on monitoring for the one or more sidelink responses, whether to transmit a sidelink confirmation indicating a reservation of the subset of the data resources to the second UE.
1. An apparatus for wireless communications at a first user equipment (UE), comprising:
a processor, and
memory coupled with the processor and storing instructions executable by the processor to cause the apparatus to:
determine shared resources for communicating over one or more sidelink communication links, the shared resources comprising control resources and data resources, the control resources in a first portion of a slot being allocated for sending a sidelink request by the first UE;
transmit, to a second UE on a transmission beam over the control resources in the first portion of the slot, the sidelink request to reserve a subset of the data resources;
monitor, by the first UE on a receive beam over control resources in a second portion of the slot, for one or more sidelink responses from one or more UEs, the one or more sidelink responses indicating a positive sidelink response to the sidelink request to reserve the subset of the data resources, a negative sidelink response to the sidelink request to reserve the subset of the data resources, or both, the control resources in the second portion of the slot being allocated for the one or more sidelink responses; and
determine, based at least in part on the monitoring, whether to transmit a sidelink confirmation indicating a reservation of the subset of the data resources to the second UE over control resources in a third portion of the slot, the control resources in the third portion of the slot being allocated for the sidelink confirmation.
2. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, based at least in part on the monitoring, a positive sidelink response of the one or more sidelink responses from the second UE; and
transmit, based at least in part on receiving the positive sidelink response from the second UE, the sidelink confirmation to the second UE over the control resources in the third portion of the slot.
3. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, based at least in part on the monitoring, a positive sidelink response of the one or more sidelink responses from the second UE;
receive, based at least in part on the monitoring, a negative sidelink response of the one or more sidelink responses from a third UE, wherein the positive sidelink response and the negative sidelink response are multiplexed in the control resources in the second portion of the slot; and
refrain, based at least in part on receiving the positive sidelink response and the negative sidelink response, from transmitting the sidelink confirmation to the second UE over the control resources in the third portion of the slot.
4. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine, based at least in part on the monitoring, that none of the one or more sidelink responses have been received, wherein determining whether to transmit the sidelink confirmation comprises determining not to transmit the sidelink confirmation based at least in part on determining that none of the one or more sidelink responses have been received; and
refrain from transmitting the sidelink confirmation to the second UE over the control resources in the third portion of the slot.
5. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to perform a beam training procedure with UEs of a set of UEs comprising the second UE, wherein transmitting the sidelink request on the transmission beam is based at least in part on the beam training procedure.
6. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, from a network device, a control resource allocation indicating that one or more slots in the control resources are allocated to a set of UEs for reserving the data resources, wherein the set of UEs comprises the first UE and the second UE; and
determine that the control resources in the first portion of the slot are allocated for sending the sidelink request by the first UE based at least in part on the control resource allocation.
7. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
compare a UE identifier of the first UE to one or more UE identifiers of a set of UEs comprising the first UE and the second UE; and
determine that the control resources in the first portion of the slot are allocated for sending the sidelink request by the first UE based at least in part on the comparing.
8. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine a rotating schedule for slot allocation; and
determine that the control resources in the first portion of the slot are allocated for sending the sidelink request by the first UE based at least in part on the rotating schedule.
9. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
determine a preconfigured slot allocation assignment; and
determine that the control resources in the first portion of the slot are allocated for sending the sidelink request by the first UE based at least in part on the preconfigured slot allocation assignment.
10. A method for wireless communications at a first user equipment (UE), comprising:
determining shared resources for communicating over one or more sidelink communication links, the shared resources comprising control resources and data resources, the control resources in a first portion of a slot being allocated for sending a sidelink request by the first UE;
transmitting, to a second UE on a transmission beam over the control resources in the first portion of the slot, the sidelink request to reserve a subset of the data resources;
monitoring, by the first UE on a receive beam over control resources in a second portion of the slot, for one or more sidelink responses from one or more UEs, the one or more sidelink responses indicating a positive sidelink response to the sidelink request to reserve the subset of the data resources, a negative sidelink response to the sidelink request to reserve the subset of the data resources, or both, the control resources in the second portion of the slot being allocated for the one or more sidelink responses; and
determining, based at least in part on the monitoring, whether to transmit a sidelink confirmation indicating a reservation of the subset of the data resources to the second UE over control resources in a third portion of the slot, the control resources in the third portion of the slot being allocated for the sidelink confirmation.
11. The method of claim 10 , further comprising:
receiving, based at least in part on the monitoring, a positive sidelink response of the one or more sidelink responses from the second UE; and
transmitting, based at least in part on receiving the positive sidelink response from the second UE, the sidelink confirmation to the second UE over the control resources in the third portion of the slot.