Micro sleep techniques in star topology sidelink communications
Methods, systems, and devices for wireless communications are described. A hub user equipment (UE) in a star topology may broadcast to a set of peripheral UEs indicating slots when the hub UE will not be in a transmission mode. The hub UE may broadcast a slot format indication to the peripheral UEs to indicate operating modes in a set of slots. In a first group of slots, the hub UE may operate in a forward mode, transmitting sidelink communications to the peripheral UEs. In a second group of slots, the hub UE may operate in a reverse mode, receiving sidelink communications from the peripheral UEs. In slots when the hub UE operates in the reverse mode, if a peripheral UE does not have data or control information, the peripheral UE may enter a sleep mode in one or more slots of the second group to save power.
1. An apparatus for wireless communications implemented by a second user equipment (UE), comprising:
a processor; and
memory coupled with the processor,
wherein the memory comprises instructions executable by the processor to cause the apparatus to:
receive, from a first UE, a slot format indication that indicates respective operation modes for sidelink communications in a set of slots, each operation mode selected from a set of operation modes; and
communicate, based at least in part on the receiving the slot format indication, with the first UE in one or more slots of the set of slots based at least in part on a first operation mode corresponding to a first subset of the set of slots and a second operation mode corresponding to a second subset of the set of slots, wherein the second UE is operable to enter a sleep mode in at least a portion of a slot of the second subset of slots corresponding to the second operation mode based at least in part on a quantity of data associated with transmitting one or more second sidelink transmissions to the first UE being less than a threshold.
2. The apparatus of claim 1 , wherein the slot format indication comprises an array indicating the set of slots and the respective operation modes.
3. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, from the first UE, a first sidelink transmission in one or more slots of the first subset based at least in part on the first operation mode.
4. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
transmit, to the first UE, a second sidelink transmission in one or more slots of the second subset based at least in part on the second operation mode.
5. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
enter the sleep mode in at least the portion of the slot of the second subset based at least in part on the quantity of data associated with transmitting the one or more second sidelink transmissions to the first UE being less than the threshold and determining the second operation mode; and
refrain from communicating with the first UE in at least the portion of the slot of the second subset based at least in part on the entering the sleep mode.
6. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive the slot format indication in a sidelink control information message.
7. The apparatus of claim 6 , wherein the sidelink control information message comprises an indication of the slot format indication and a network identifier associated with the first UE and the second UE.
8. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
enter the sleep mode in at least a portion of a slot of a third subset of the set of slots based at least in part on a third operation mode corresponding to the third subset; and
refrain from communicating with the first UE in at least the portion of the slot of the third subset based at least in part on the entering the sleep mode.
9. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive, from the first UE, a feedback indication that indicates a fourth subset of the set of slots for feedback associated with the sidelink communications; and
communicate the feedback with the first UE in one or more slots of the fourth subset based at least in part on the respective operation mode for each slot of the fourth subset and the receiving the feedback indication.
10. The apparatus of claim 9 , wherein the instructions are further executable by the processor to cause the apparatus to:
refrain from communicating the feedback with the first UE in a first slot of the fourth subset based at least in part on the respective operation mode for the first slot; and
communicate the feedback with the first UE in a second slot of the fourth subset based at least in part on the respective operation mode for the second slot.
11. The apparatus of claim 1 , wherein the slot format indication indicates respective operation modes for a set of subbands in each slot of the set of slots.
12. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive the slot format indication in one or more sub-channels of a set of sub-channels.
13. The apparatus of claim 1 , wherein the instructions are further executable by the processor to cause the apparatus to:
receive the slot format indication in a medium access control control element, a radio resource control message, or any combination thereof.
14. A method for wireless communications implemented by a second user equipment (UE), comprising:
receiving, from a first UE, a slot format indication that indicates respective operation modes for sidelink communications in a set of slots, each operation mode selected from a set of operation modes; and
communicating, based at least in part on the receiving the slot format indication, with the first UE in one or more slots of the set of slots based at least in part on a first operation mode corresponding to a first subset of the set of slots and a second operation mode corresponding to a second subset of the set of slots, wherein the second UE is operable to enter a sleep mode in at least a portion of a slot of the second subset of slots corresponding to the second operation mode based at least in part on a quantity of data associated with transmitting one or more second sidelink transmissions to the first UE being less than a threshold.
15. The method of claim 14 , further comprising:
identifying an array indicating the set of slots and the respective operation modes, wherein the slot format indication comprises the array.