Collecting buffered CSI from a UE

1. A method of wireless communication at a user equipment (UE), comprising:

receiving a plurality of data transmissions from a base station;

storing in a channel state information (CSI) buffer, channel state information to include in a CSI report;

discarding from the CSI buffer expired CSIs or CSIs send in a previous CSI report;

identifying a channel state information (CSI) report trigger event; and

sending the CSI report comprising a plurality of CSIs, the plurality of CSIs including a CSI for each of the plurality of data transmissions in response to the CSI report trigger event.

2. The method of claim 1 , wherein the CSI report trigger event comprises an acknowledgment of one of the plurality of data transmissions, the one of the plurality of data transmissions having:

a quality of log-likelihood ratios (LLRs) below a quality threshold; or

a signal-to-noise ratio (SNR) associated with a block error rate (BLER) above a BLER threshold.

3. The method of claim 2 , wherein the acknowledgment is indicated in a first-stage uplink control information (UCI) and the CSI report is sent in a second-stage UCI.

4. The method of claim 1 , wherein the CSI report trigger event comprises X non-acknowledgments in response to L data transmissions of the plurality of data transmissions, wherein 1≤X≤L.

5. The method of claim 1 , wherein the CSI report trigger event comprises an indication in downlink control information (DCI).

6. The method of claim 1 ,

wherein the CSIs included in the CSI report comprise MCSIs for a latest N obtained data transmissions, and

wherein a value of M is in a CSI report configuration, Nis based on UE capability, and M≤N.

7. The method of claim 1 , wherein the CSIs included in the CSI report are indicated in a bitmap from the base station.

8. The method of claim 1 , wherein the CSIs included in the CSI report comprise:

first CSI for each of the data transmissions triggering a non-acknowledgment, and

second CSI for each of the data transmissions triggering an acknowledgment,

wherein each of the acknowledgments is prior to each of the non-acknowledgments.

9. The method of claim 1 , further comprising:

determining to include, in the CSI report, M′ CSIs of M CSIs for a latest N obtained data transmissions,

wherein a value of M is in a CSI report configuration, the CSI report includes the M′ CSIs, and M′<M≤N.

10. The method of claim 9 , wherein a value of M′ is indicated in a first-stage uplink control information (UCI) and the CSI report is sent in a second-stage UCI.

11. The method of claim 1 , wherein each of the CSIs include an expiration time following the CSI report trigger event.

12. The method of claim 11 , wherein the expiration time for each of the CSIs is in a radio resource control (RRC) configuration or a medium access control (MAC) control element (MAC-CE).

13. The method of claim 1 , wherein the CSI report excludes CSIs sent in a previous CSI report.

14. The method of claim 1 , wherein the CSI report further includes an average channel quality indicator (CQI) for the data transmissions.

15. An apparatus for wireless communication, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:

receive a plurality of data transmissions from a base station;

store in a channel state information (CSI) buffer CSIs to include in a CSI report;

discard from the CSI buffer expired CSIs or CSIs sent in a previous CSI report;

identify a channel state information (CSI) report trigger event; and

send the CSI report comprising a plurality of CSIs, the plurality of CSIs including a CSI for each of the plurality of data transmissions in response to the CSI report trigger event.

16. The apparatus of claim 15 ,

wherein the CSIs included in the CSI report comprise M CSIs for a latest N obtained data transmissions, and

wherein a value of M is in a CSI report configuration, Nis based on UE capability, and M≤N.

17. The apparatus of claim 15 , wherein the CSIs included in the CSI report are indicated in a bitmap from the base station.

18. The apparatus of claim 15 , wherein the CSIs included in the CSI report comprise:

first CSI for each of the data transmissions triggering a non-acknowledgment, and

second CSI for each of the data transmissions triggering an acknowledgment,

wherein each of the acknowledgments is prior to each of the non-acknowledgments.

19. The apparatus of claim 15 , wherein the instructions, when executed by the processor, further cause the apparatus to:

determine to include, in the CSI report, M′ CSIs of M CSIs for a latest N obtained data transmissions,

wherein a value of M is in a CSI report configuration, the CSI report includes the M′ CSIs, and M′<M≤N.

20. A method of wireless communication at a base station, comprising:

sending a plurality of data transmissions to a user equipment (UE);

configuring a channel state information (CSI) report trigger event; and

receiving a CSI report comprising a plurality of CSIs, the plurality of CSIs including a CSI for each of the plurality of data transmissions in response to the CSI report trigger event wherein the CSIs included in the CSI report comprise M CSIs for a latest N sent data transmissions, and wherein a value of M is in a CSI report configuration, Nis based on UE capability, and M N.

21. The method of claim 20 , wherein the CSIs included in the CSI report are indicated in a bitmap.

22. The method of claim 20 , wherein the CSIs included in the CSI report comprise:

first CSI for each of the data transmissions triggering a non-acknowledgment, and

second CSI for each of the data transmissions triggering an acknowledgment,

wherein each of the acknowledgments is prior to each of the non-acknowledgments.

23. The method of claim 20 ,

wherein the CSIs included in the CSI report comprise M′ CSIs of M CSIs for a latest N sent data transmissions,

wherein a value of M is in the CSI report configuration, the CSI report includes the M′ CSIs, and M′<M≤N.

24. An apparatus for wireless communication, comprising:

a processor;

memory coupled with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:

send a plurality of data transmissions to a user equipment (UE);

configure a channel state information (C SI) report trigger event; and

receive a CSI report including a CSI for each of the plurality of data transmissions in response to the CSI report trigger event, wherein the CSIs included in the CSI report comprise M CSIs for a latest N sent data transmissions, and

wherein a value of M is in a CSI report configuration, Nis based on UE capability, and M≤N.

25. The apparatus of claim 24 , wherein the CSIs included in the CSI report are indicated in a bitmap.

26. The apparatus of claim 24 ,

wherein the CSIs included in the CSI report comprise M′ CSIs of M CSIs for a latest N sent data transmissions, and

the CSI report includes the M′ CSIs, and M′<M≤N.