Identifying a hybrid automatic repeat request mode

1. A method for wireless communications at a user equipment (UE), comprising:

receiving a downlink control message that supports indicating one of a plurality of modes for reporting hybrid automatic repeat request feedback, wherein a first mode of the plurality of modes supports reporting hybrid automatic repeat request feedback and channel information according to a bundling configuration, and a second mode of the plurality of modes supports reporting hybrid automatic repeat request feedback according to a standalone configuration;

determining to use the first mode for transmitting the hybrid automatic repeat request feedback and the channel information based at least in part on the downlink control message, wherein a plurality of values corresponds to a plurality of combinations of hybrid automatic repeat request feedback and channel information;

determining a first index of a channel quality indicator or a modulation and coding scheme (MCS), wherein a data transmission is based at least in part on the first index;

failing to decode the data transmission;

determining a second index of the channel quality indicator or the MCS;

selecting, based at least in part on determining to use the first mode, one of the plurality of values based at least in part on a difference between the first index and the second index; and

transmitting the hybrid automatic repeat request feedback and the channel information according to the first mode, wherein the transmitted hybrid automatic repeat request feedback and the transmitted channel information comprises the selected one of the plurality of values.

2. The method of claim 1 , further comprising:

bundling the hybrid automatic repeat request feedback with the channel information based at least in part on determining to use the first mode, wherein the hybrid automatic repeat request feedback and the channel information are transmitted after the bundling.

3. The method of claim 1 , further comprising:

identifying a channel state information reference signal resource based at least in part on an indication of the channel state information reference signal resource included in the downlink control message, wherein the channel information is determined based at least in part on the channel state information reference signal resource.

4. The method of claim 1 , further comprising:

identifying an uplink control resource based at least in part on determining to use the first mode, wherein the hybrid automatic repeat request feedback and the channel information are transmitted in the uplink control resource.

5. The method of claim 1 , further comprising:

identifying a plurality of uplink control resources based at least in part on determining to use the first mode, wherein the hybrid automatic repeat request feedback is transmitted in a first uplink control resource of the plurality of uplink control resources and the channel information is transmitted in a second uplink control resource of the plurality of uplink control resources.

6. The method of claim 5 , wherein the downlink control message comprises an indicator that triggers the UE to report the channel information, an indication of a timing for transmitting the channel information, an indication of an uplink control resource for transmitting the channel information, an indication of a power for transmitting the channel information, or any combination thereof.

7. The method of claim 1 , further comprising:

receiving a downlink data transmission based at least in part on the downlink control message;

determining that a decoding of the downlink data transmission was successful; and

refraining from bundling the hybrid automatic repeat request feedback with the channel information based at least in part on the decoding being successful, wherein transmitting the hybrid automatic repeat request feedback and the channel information comprises transmitting the hybrid automatic repeat request feedback without the channel information.

8. The method of claim 7 , further comprising:

identifying a plurality of uplink control resources based at least in part on determining to use the first mode, wherein a first uplink control resource of the plurality of uplink control resources is configured for transmissions of hybrid automatic repeat request feedback and a second uplink control resource of the plurality of uplink control resources is configured for transmissions of bundled hybrid automatic repeat request feedback and channel information.

9. The method of claim 1 , further comprising:

receiving a downlink data transmission based at least in part on the downlink control message;

determining that a decoding of the downlink data transmission was unsuccessful; and

bundling the hybrid automatic repeat request feedback with the channel information based at least in part on the decoding being unsuccessful.

10. The method of claim 9 , further comprising:

identifying a plurality of uplink control resources based at least in part on determining to use the first mode, wherein a first uplink control resource of the plurality of uplink control resources is configured for transmissions of hybrid automatic repeat request feedback and a second uplink control resource of the plurality of uplink control resources is configured for transmissions of bundled hybrid automatic repeat request feedback and channel information.

11. The method of claim 10 , wherein the hybrid automatic repeat request feedback and channel information is transmitted over the second uplink control resource based at least in part on the decoding being unsuccessful.

12. The method of claim 1 , wherein the second index of the channel quality indicator is based at least in part on a signal strength for the data transmission.

13. The method of claim 1 , wherein:

a first value of the plurality of values corresponds to a successful decoding of the data transmission;

a second value of the plurality of values corresponds to an unsuccessful decoding of the data transmission and a first channel measurement;

a third value of the plurality of values corresponds to the unsuccessful decoding of the data transmission and a second channel measurement; and

a fourth value of the plurality of values corresponds to the unsuccessful decoding of the data transmission and a third channel measurement.

14. The method of claim 13 , wherein the second value corresponds to a missed downlink control message.

15. The method of claim 1 , wherein:

a first value of the plurality of values corresponds to an unsuccessful decoding of the data transmission and a first channel measurement;

a second value of the plurality of values corresponds to the unsuccessful decoding of the data transmission and a second channel measurement;

a third value of the plurality of values corresponds to the unsuccessful decoding of the data transmission and a third channel measurement; and

a fourth value of the plurality of values corresponds to the unsuccessful decoding of the data transmission and a fourth channel measurement.

16. The method of claim 15 , wherein the first value corresponds to a missed downlink control message.

17. The method of claim 1 , wherein:

a first value of the plurality of values corresponds to a successful decoding of the data transmission;

a second value of the plurality of values corresponds to an unsuccessful decoding of the data transmission; and

a third value of the plurality of values corresponds to a missed downlink control message.

18. The method of claim 17 , wherein a fourth value of the plurality of values corresponds to the unsuccessful decoding of the data transmission and a first channel measurement.

19. The method of claim 1 , wherein the determining comprises:

decoding an indicator field in the downlink control message, the indicator field comprising an indication of the first mode; and

activating the first mode based at least in part on the indication of the first mode.

20. The method of claim 19 , further comprising:

receiving a second downlink control message that supports indicating one of the plurality of modes for reporting hybrid automatic repeat request feedback;

decoding the indicator field in the second downlink control message, the indicator field comprising a second indication of the second mode;

activating the second mode based at least in part on the second indication; and

transmitting second hybrid automatic repeat request feedback according to the second mode.

21. The method of claim 1 , wherein the determining comprises:

identifying a format of the downlink control message;

determining that the format of the downlink control message corresponds to the first mode; and

activating the first mode based at least in part on the format of the downlink control message.

22. The method of claim 21 , further comprising:

receiving a second downlink control message that supports indicating one of the plurality of modes for reporting hybrid automatic repeat request feedback;

determining that a second format of the second downlink control message corresponds to the second mode;

activating the second mode based at least in part on the format of the second downlink control message; and

transmitting second hybrid automatic repeat request feedback according to the second mode.

23. The method of claim 1 , wherein the determining comprises:

receiving a radio resource control message;

decoding an indicator field in the radio resource control message, the indicator field comprising an indication of the first mode; and

activating the first mode based at least in part on the indication of the first mode.

24. A method for wireless communications at an access network entity, comprising:

transmitting a downlink control message that supports indicating one of a plurality of modes for reporting hybrid automatic repeat request feedback, wherein a first mode of the plurality of modes supports reporting hybrid automatic repeat request feedback and channel information according to a bundling configuration, and a second mode of the plurality of modes supports reporting hybrid automatic repeat request feedback according to a standalone configuration;

determining to use the first mode for receiving the hybrid automatic repeat request feedback and the channel information based at least in part on the downlink control message; and

receiving, based at least in part on the first mode being indicated by the downlink control message, the hybrid automatic repeat request feedback and the channel information according to the first mode, wherein the received hybrid automatic repeat request feedback and the channel information comprises a value of a plurality of values corresponding to a plurality of combinations of hybrid automatic repeat request feedback and channel information, wherein the value is based at least in part on a difference between a first index of a channel quality indicator or a modulation and coding scheme (MCS) associated with a data transmission and a second index of the channel quality indicator or the MCS measured after a decoding failure for the data transmission.

25. The method of claim 24 , further comprising:

scheduling a plurality of uplink control resources based at least in part on determining to use the first mode, wherein the hybrid automatic repeat request feedback is received in a first uplink control resource of the plurality of uplink control resources and the channel information is received in a second uplink control resource of the plurality of uplink control resources that occurs after the first uplink control resource,

wherein the downlink control message comprises an indicator that triggers a user equipment (UE) to report the channel information, an indication of a timing for the UE to transmit the channel information, an indication of an uplink control resource for transmitting the channel information, an indication of a power for transmitting the channel information, or any combination thereof.

26. The method of claim 24 , further comprising:

setting an indicator field in the downlink control message to indicate the first mode; and

activating the first mode based at least in part on the indication.

27. An apparatus for wireless communications at a user equipment (UE), comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

receive a downlink control message that supports indicating one of a plurality of modes for reporting hybrid automatic repeat request feedback, wherein a first mode of the plurality of modes supports reporting hybrid automatic repeat request feedback and channel information according to a bundling configuration, and a second mode of the plurality of modes supports reporting hybrid automatic repeat request feedback according to a standalone configuration;

determine to use the first mode for transmitting the hybrid automatic repeat request feedback and the channel information based at least in part on the downlink control message, wherein a plurality of values corresponds to a plurality of combinations of hybrid automatic repeat request feedback and channel information;

determine a first index of a channel quality indicator or a modulation and coding scheme (MCS), wherein a data transmission is based at least in part on the first index;

fail to decode the data transmission;

determine a second index of the channel quality indicator or the MCS;

select, based at least in part on determining to use the first mode, one of the plurality of values based at least in part on a difference between the first index and the second index; and

transmit the hybrid automatic repeat request feedback and the channel information according to the first mode, wherein the transmitted hybrid automatic repeat request feedback and the transmitted channel information comprises the selected one of the plurality of values.

28. An apparatus for wireless communications at an access network entity, comprising:

a processor,

memory coupled with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

transmit a downlink control message that supports indicating one of a plurality of modes for reporting hybrid automatic repeat request feedback, wherein a first mode of the plurality of modes supports reporting hybrid automatic repeat request feedback and channel information according to a bundling configuration, and a second mode of the plurality of modes supports reporting hybrid automatic repeat request feedback according to a standalone configuration;

determine to use the first mode for receiving the hybrid automatic repeat request feedback and the channel information based at least in part on the downlink control message; and

receive, based at least in part on the first mode being indicated by the downlink control message, the hybrid automatic repeat request feedback and the channel information according to the first mode, wherein the received hybrid automatic repeat request feedback and the channel information comprises a value of a plurality of values corresponding to a plurality of combinations of hybrid automatic repeat request feedback and channel information, wherein the value is based at least in part on a difference between a first index of a channel quality indicator or a modulation and coding scheme (MCS) associated with a data transmission and a second index of the channel quality indicator or the MCS measured after a decoding failure for the data transmission.