Multiple transmission and reception point coherent joint transmission channel state information feedback

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

receiving a respective reference signal from each of a plurality of transmission reception points (TRPs);

transmitting a first message comprising a bitmap having a value that maps to a recommended set of TRPs from among the plurality of TRPs for use in coherent joint transmission (CJT) based on the respective reference signals; and

transmitting, after transmitting the first message, a second message comprising a channel state information (CSI) report based on a transmission hypothesis, wherein the transmission hypothesis is based on the recommended set of TRPs or an override set of TRPs from among the plurality of TRPs for use in CJT.

2 . The method of claim 1 , wherein the first message comprises at least one of: a recommended number of the TRPs, or at least one identifier indicating which TRPs are in the recommended set of TRPs.

3 . The method of claim 1 , wherein the first message comprises a beam selection report with group-based beam reporting enabled.

4 . The method of claim 3 , wherein the first message further comprises a set of CSI-RS Resource IDs (CRIs) corresponding to CSI-RS transmissions from TRPs in the recommended set of TRPs.

5 . The method of claim 3 , wherein the first message further comprises an information element configured to indicate that the beam selection report provides the recommended set of TRPs for use in CJT.

6 . The method of claim 5 , wherein the information element comprises one of Reference Signal Received Power (RSRP) or Signal Interference+Noise Ratio (SINR) values being set to a predetermined value.

7 . The method of claim 1 , wherein the first message comprises a dedicated message for carrying the recommended set of TRPs for use in CJT.

8 . The method of claim 1 , further comprising:

receiving, prior to transmitting the second message, a response message comprising a response to the first message to acknowledge or to modify the recommended set of TRPs for use in CJT.

9 . The method of claim 8 , wherein the response to the first message is to modify the recommended set of TRPs for use in CJT and wherein the response message further comprises the override set of TRPs.

10 . The method of claim 1 , wherein transmitting the second message is automatic and occurring after a predetermined number of slots after transmitting the first message.

11 . The method of claim 1 , further comprising:

starting a timer upon transmitting the first message; and

determining an expiry of the timer,

wherein transmitting the second message is based on a response message not being received prior to the expiry of the timer.

12 . The method of claim 11 , further comprising retransmitting the first message based on the response message not being received prior to expiry of the timer.

13 . A method of wireless communication at a network node, comprising:

transmitting a respective reference signal from each of a plurality of transmission reception points (TRPs);

receiving a first message comprising a bitmap having a value that maps to a recommended set of TRPs from among the plurality of TRPs for use in coherent joint transmission (CJT) based on the respective reference signals;

receiving, after receiving the first message, a second message comprising a channel state information (CSI) report based on a transmission hypothesis corresponding to the recommended set of TRPs or an override set of TRPs from among the plurality of TRPs for use in CJT; and

initiating multiple TRP (mTRP) CJT communication with a user equipment (UE) based on the second message.

14 . The method of claim 13 , wherein the first message comprises at least one of: a recommended number of the TRPs, or at least one identifier indicating which TRPs among the plurality of TRPs are recommended for use in CJT.

15 . The method of claim 13 , wherein the first message comprises a beam selection report with group-based beam reporting enabled.

16 . The method of claim 15 , wherein the first message further comprises a set of CSI-RS Resource IDs (CRIs) corresponding to CSI-RS transmissions from the TRPs in the recommended set of TRPs.

17 . The method of claim 15 , wherein the first message comprises a most recently received beam selection report with group-based beam reporting enabled.

18 . The method of claim 15 , wherein the first message further comprises an information element configured to indicate that the beam selection report provides the recommended set of TRPs for use in CJT.

19 . The method of claim 18 , wherein the information element comprises one of Reference Signal Received Power (RSRP) or Signal Interference+Noise Ratio (SINR) values being set to a predetermined value.

20 . The method of claim 13 , wherein the first message comprises a dedicated message for carrying the recommended set of TRPs for use in CJT.

21 . The method of claim 13 , further comprising:

transmitting, prior to receiving the second message, a response message comprising a response to the first message to acknowledge or to modify the recommended set of TRPs for use in CJT.

22 . The method of claim 21 , wherein the response to the first message is to modify the recommended set of TRPs for use in CJT and wherein the response message further comprises the override set of TRPs.

23 . A wireless communication device, comprising:

one or more processors;

one or more transceivers coupled to the one or more processors; and

memory coupled to the one or more processors,

wherein the one or more processors are configured to cause the wireless communication device to:

receive a respective reference signal from each of a plurality of transmission reception points (TRPs);

transmit a first message comprising a bitmap having a value that maps to a recommended set of TRPs from among the plurality of TRPs for use in coherent joint transmission (CJT) based on the respective reference signals; and

transmit, after transmitting the first message, a second message comprising a channel state information (CSI) report based on a transmission hypothesis, wherein the transmission hypothesis is based on the recommended set of TRPs or an override set of TRPs from among the plurality of TRPs for use in CJT.

24 . The device of claim 23 , wherein the first message comprises at least one of: a recommended number of the TRPs, or at least one identifier indicating which TRPs are in the recommended set of TRPs.

25 . The device of claim 23 , wherein the first message comprises a beam selection report with group-based beam reporting enabled.

26 . The device of claim 25 , wherein the first message further comprises a set of CSI-RS Resource IDs (CRIs) corresponding to CSI-RS transmissions from TRPs in the recommended set of TRPs.

27 . The device of claim 25 , wherein the first message further comprises an information element configured to indicate that the beam selection report provides the recommended set of TRPs for use in CJT.

28 . A network node for wireless communication, the network node comprising:

one or more processors;

one or more transceivers coupled to the one or more processors; and memory coupled to the one or more processors,

wherein the one or more processors are configured to cause the network node to:

transmit a respective reference signal from each of a plurality of transmission reception points (TRPs);

receive a first message comprising a bitmap having a value that maps to a recommended set of TRPs from among the plurality of TRPs for use in coherent joint transmission (CJT) based on the respective reference signals;

receive, after receiving the first message, a second message comprising a channel state information (CSI) report based on a transmission hypothesis corresponding to the recommended set of TRPs or an override set of TRPs from among the plurality of TRPs for use in CJT; and

initiate multiple TRP (mTRP) CJT communication with a user equipment (UE) based on the second message.

29 . The method of claim 1 , wherein the bitmap identifies the recommended set of TRPs.

30 . The method of claim 13 , wherein the bitmap identifies the recommended set of TRPs.