Techniques and apparatuses for HARQ-ACK timeline indication and HARQ-ACK multiplexing and bundling in new radio
Aspects of the present disclosure relate to wireless communication. In some aspects, a user equipment (UE) may receive a downlink grant that does not include a downlink assignment index (DAI); determine a pre-defined bundle window, associated with ACK/NACK multiplexing or bundling, based at least in part on receiving the downlink grant that does not include the DAI; and transmit ACK/NACK feedback to acknowledge or negatively acknowledge one or more downlink communications received in the pre-defined bundle window. In some aspects, a UE may receive a downlink grant that does not include a DAI; determine a bundle window, associated with ACK/NACK multiplexing or bundling, based at least in part on receiving the downlink grant that does not include the DAI, wherein the bundle window is not pre-defined; and transmit ACK/NACK feedback to acknowledge or negatively acknowledge one or more downlink communications received in the bundle window. Numerous other aspects are provided.
1. A method of wireless communication performed by a user equipment (UE), comprising:
receiving a downlink grant that does not include a downlink assignment index (DAI);
determining a pre-defined bundle window, associated with acknowledgement/negative acknowledgement (ACK/NACK) multiplexing or bundling, based at least in part on receiving the downlink grant that does not include the DAI, wherein the pre-defined bundle window includes a fixed number of slots;
receiving an uplink grant for ACK/NACK feedback that indicates one or more slots, of the fixed number of slots, in which one or more downlink communications were scheduled; and
transmitting the ACK/NACK feedback to acknowledge or negatively acknowledge the one or more downlink communications received in the pre-defined bundle window, wherein the ACK/NACK feedback indicates information for each slot of the fixed number of slots.
2. The method of claim 1 , wherein the information includes ACK, NACK, or discontinuous transmission (DTX) for each slot included in the fixed number of slots.
3. The method of claim 1 , wherein the one or more slots are indicated using at least one of:
a bitmap,
an index corresponding to a pre-defined slot pattern, or
some combination thereof.
4. The method of claim 1 , wherein information regarding the fixed number of slots is indicated in a radio resource control (RRC) configuration message.
5. The method of claim 1 , wherein the uplink grant includes information that indicates, for a slot of the fixed number of slots, whether a downlink communication was scheduled for the slot.
6. The method of claim 5 , wherein the information includes an index corresponding to a pre-defined slot pattern.
7. A method of wireless communication performed by a user equipment (UE), comprising:
receiving a downlink grant that does not include a downlink assignment index (DAI);
determining a bundle window, associated with acknowledgement/negative acknowledgement (ACK/NACK) multiplexing or bundling, based at least in part on a timing indication included in the downlink grant that does not include the DAI, wherein the bundle window is not pre-defined, wherein the timing indication indicates a number of slots between reception of a downlink communication and an ACK/NACK indication corresponding to the downlink communication, and wherein the timing indication indicates a start of the bundle window; and
transmitting ACK/NACK feedback to acknowledge or negatively acknowledge one or more downlink communications received in the bundle window.
8. The method of claim 7 , further comprising indicating the start of the bundle window to a base station.
9. The method of claim 7 , wherein the bundle window is determined based at least in part on an indication received from a base station.
10. The method of claim 9 , wherein the indication is an uplink grant for the ACK/NACK feedback that indicates the start of the bundle window.
11. The method of claim 7 , wherein the bundle window is determined based at least in part on a maximum bundle window size.
12. The method of claim 11 , wherein the maximum bundle window size is determined based at least in part on a maximum timing indication value or a maximum number of possible timing indication values.
13. A user equipment (UE) for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
receive a downlink grant that does not include a downlink assignment index (DAI);
determine a pre-defined bundle window, associated with acknowledgement/negative acknowledgement (ACK/NACK) multiplexing or bundling, based at least in part on receiving the downlink grant that does not include the DAI, wherein the pre-defined bundle window includes a fixed number of slots;
receive an uplink grant for ACK/NACK feedback that indicates one or more slots, of the fixed number of slots, in which one or more downlink communications were scheduled; and
transmit the ACK/NACK feedback to acknowledge or negatively acknowledge the one or more downlink communications received in the pre-defined bundle window, wherein the ACK/NACK feedback indicates information for each slot of the fixed number of slots.
14. The UE of claim 13 , wherein the information includes ACK, NACK, or discontinuous transmission (DTX) for each slot included in the fixed number of slots.
15. The UE of claim 13 , wherein the one or more slots are indicated using at least one of:
a bitmap,
an index corresponding to a pre-defined slot pattern, or
some combination thereof.
16. The UE of claim 13 , wherein information regarding the fixed number of slots is indicated in a radio resource control (RRC) configuration message.
17. The UE of claim 13 , wherein the uplink grant includes information that indicates, for a slot of the fixed number of slots, whether a downlink communication was scheduled for the slot.
18. The UE of claim 17 , wherein the information includes an index corresponding to a pre-defined slot pattern.
19. A user equipment (UE) for wireless communication, comprising:
a memory; and
one or more processors operatively coupled to the memory, the memory and the one or more processors configured to:
receive a downlink grant that does not include a downlink assignment index (DAI);
determine a bundle window, associated with acknowledgement/negative acknowledgement (ACK/NACK) multiplexing or bundling, based at least in part on a timing indication included in the downlink grant that does not include the DAI, wherein the bundle window is not pre-defined, wherein the timing indication indicates a number of slots between reception of a downlink communication and an ACK/NACK indication corresponding to the downlink communication, and wherein the timing indication indicates a start of the bundle window; and
transmit ACK/NACK feedback to acknowledge or negatively acknowledge one or more downlink communications received in the bundle window.
20. The UE of claim 19 , further comprising indicating the start of the bundle window to a base station.
21. The UE of claim 19 , wherein the bundle window is determined based at least in part on an indication received from a base station.
22. The UE of claim 21 , wherein the indication is an uplink grant for the ACK/NACK feedback that indicates the start of the bundle window.
23. The UE of claim 19 , wherein the bundle window is determined based at least in part on a maximum bundle window size.
24. The UE of claim 23 , wherein the maximum bundle window size is determined based at least in part on a maximum timing indication value or a maximum number of possible timing indication values.