Sidelink CSI report transmission methods and conditions

1. An apparatus for wireless communication by a first wireless device, the apparatus comprising:

a receiver configured to receive one or more instances of channel state information reference signals (CSI-RS);

at least one processor configured to:

generate one or more CSI reports for one or more of the CSI-RS instances; and

determine whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission from the first wireless device is less than or equal to a maximum time delay; and

a transmitter configured to:

transmit a first CSI report, of the one or more CSI reports, for the first CSI-RS instance, being multiplexed with data in a physical sidelink shared channel (PSSCH) transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; and

transmit the first CSI report, of the one or more CSI reports, for the first CSI-RS instance, without multiplexing the first CSI report with the data in the PSSCH transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay.

2. The apparatus of claim 1 , wherein the one or more CSI reports comprises at least a channel quality indicator (CQI) and a rank indicator (RI).

3. The apparatus of claim 1 , wherein the receiver is further configured to receive radio resource control (RRC) signaling indicating a value of the maximum time delay.

4. The apparatus of claim 1 , wherein the first wireless device is configured to trigger the transmission of the one or more CSI reports on the PSSCH transmission with time for the first wireless device to prepare the PSSCH transmission with the one or more CSI reports.

5. The apparatus of claim 1 , wherein the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by:

generating the one or more CSI reports for only a last received CSI-RS; or

generating the one or more CSI reports for the one or more CSI-RS instances that are received within a window.

6. The apparatus of claim 5 , wherein the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating the one or more CSI reports for the one or more CSI-RS instances that are received within a window, and wherein the window is based on a maximum time delay between reception of a CSI-RS instance of the CSI-RS instances and a transmission instance of a corresponding CSI report of the one or more CSI reports.

7. The apparatus of claim 1 , wherein the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating a channel quality indicator (CQI):

as a mean CQI estimated over the one or more CSI-RS instances;

as a minimum CQI estimated over the one or more CSI-RS instances;

as a maximum CQI estimated over the one or more CSI-RS instances; or

relative to a given statistic for CQI estimated over the one or more CSI-RS instances.

8. The apparatus of claim 1 , wherein the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating a rank indicator (RI) as:

a minimum RI estimated over the one or more CSI-RS instances; or

a maximum RI estimated over the one or more CSI-RS instances.

9. The apparatus of claim 1 , wherein:

the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating an individual CSI report for each of the one or more CSI-RS instances; and

the transmitter is configured to transmit the individual CSI report along with an indication of a quantity of the individual CSI reports transmitted.

10. The apparatus of claim 1 , wherein:

the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating an individual CSI report for each of the one or more CSI-RS instances; and

the transmitter is configured to transmit, in at least one medium access control (MAC) control element (MAC CE), the individual CSI report multiplexed with the data.

11. The apparatus of claim 10 , wherein:

each CSI report of the one or more CSI reports is included in an individual MAC CE; or

a single MAC CE contains all of the CSI reports.

12. The apparatus of claim 1 , wherein when the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay, the one or more CSI reports are bit multiplexed with the data.

13. The apparatus of claim 1 , wherein when the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay, the one or more CSI reports are resource element (RE) multiplexed with the data.

14. A method for wireless communication by a first wireless device, comprising:

receiving one or more instances of channel state information reference signals (CSI-RS);

generating one or more CSI reports for one or more of the CSI-RS instances;

determining whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission from the first wireless device is less than or equal to a maximum time delay;

transmitting a first CSI report, of the one or more CSI reports, for the first CSI-RS instance, being multiplexed with data in a physical sidelink shared channel (PSSCH) transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; and

transmitting the first CSI report, of the one or more CSI reports, for the first CSI-RS instance, without multiplexing the first CSI report with the data in the PSSCH transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay.

15. An apparatus for wireless communication by a first wireless device, the apparatus comprising:

means for receiving one or more instances of channel state information reference signals (CSI-RS);

means for generating one or more CSI reports for one or more of the CSI-RS instances;

means for determining whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission from the first wireless device to a second wireless device is less than or equal to a maximum time delay;

means for transmitting a first CSI report, of the one or more CSI reports, for the first CSI-RS instance, being multiplexed with data in a physical sidelink shared channel (PSSCH) transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; and

means for transmitting the first CSI report, of the one or more CSI reports, for the first CSI-RS instance, without multiplexing the first CSI report with the data in the PSSCH transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay.

16. A non-transitory computer readable medium having instructions stored thereon that, when executed by one or more processors, cause an apparatus to:

receive one or more instances of channel state information reference signals (CSI-RS);

generate one or more CSI reports for one or more of the CSI-RS instances;

determine whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission is less than or equal to a maximum time delay;

transmit a first CSI report, of the one or more CSI reports, for the first CSI-RS instance, being multiplexed with data in a physical sidelink shared channel (PSSCH) transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; and

transmit the first CSI report, of the one or more CSI reports, for the first CSI-RS instance, without multiplexing the first CSI report with the data in the PSSCH transmission when the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay.

17. The apparatus of claim 1 , wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance of the CSI-RS instances and a transmission instance of a corresponding CSI report of the one or more CSI reports.

18. The method of claim 14 , wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance of the CSI-RS instances and a transmission instance of a corresponding CSI report of the one or more CSI reports.

19. The apparatus of claim 15 , wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance of the CSI-RS instances and a transmission instance of a corresponding CSI report of the one or more CSI reports.

20. The non-transitory computer readable medium of claim 16 , wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance of the CSI-RS instances and a transmission instance of a corresponding CSI report of the one or more CSI reports.