Beam sweep based random access msg 1 and msg 2

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

transmitting at least two first random access messages (Msg 1) directed to different transmission reception points (TRPs) of multiple TRPs for at least one cell using different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; and

monitoring, after transmitting the at least two first random access messages, for at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell based on the different time resources or the different frequency resources for the multiple TRPs.

2. The method of claim 1 , wherein the different resources further comprise different spatial resources.

3. The method of claim 1 , wherein the different resources for the multiple TRPs comprise at least the different frequency resources.

4. The method of claim 1 , wherein the different resources for the multiple TRPs comprise at least the different time resources.

5. The method of claim 1 , further comprising:

receiving a configuration for random access with the at least one cell having the multiple TRPs.

6. The method of claim 1 , wherein the at least one cell comprises a primary cell (PCell) for the UE, a secondary cell (SCell) for the UE, or a primary secondary cell (PSCell) for the UE.

7. The method of claim 1 , wherein each first random access message includes a preamble, and wherein the UE transmits the at least two first random access messages using a number of transmitting beams associated with reference signals corresponding to a number of receiving beams from the at least one cell during a corresponding number of allocated random access occasions, with each random access occasion being associated with a reference signal for receiving the preamble.

8. The method of claim 7 , wherein the reference signals include at least one of a synchronization signal block (SSB) or a channel state information-reference signal (CSI-RS) from the at least one cell.

9. The method of claim 7 , wherein the reference signals are received from the multiple TRPs for a single cell.

10. The method of claim 7 , wherein the at least two first random access messages are time division multiplexed on the number of transmitting beams.

11. The method of claim 7 , wherein the at least two first random access messages are frequency division multiplexed on the number of transmitting beams.

12. The method of claim 7 , wherein the UE transmits a first preamble for reception by a first receive beam selected from a first random access resource candidate beam pool for a cell and transmits a second preamble for reception by a second receive beam selected from a second random access resource candidate beam pool for the cell, the first receive beam being for a first transmission reception point (TRP) of the cell, and the second receive beam being for a second TRP of the cell.

13. The method of claim 12 , further comprising:

receiving, from a base station, an indication of a random access beam pool index per reference signal from the cell.

14. The method of claim 1 , further comprising:

receiving, from a base station, an indication of a beam sweep for the at least two second random access messages for the UE.

15. The method of claim 1 , wherein the UE receives a control channel of the at least two second random access messages that is transmitted with a number of beams based on multiple reference signals, wherein the number of beams are transmitted from the multiple TRPs.

16. The method of claim 1 , wherein the UE receives a control channel of the at least two second random access messages that is transmitted with a single beam per random access beam pool, wherein the UE receives an indication of each random access beam pool in radio resource control (RRC) signaling, wherein the UE receives a configuration of a reference signal index per random access beam pool, and wherein multiple random access beam pools are for the multiple TRPs.

17. The method of claim 1 , wherein the UE monitors for multiple physical downlink shared channels (PDSCHs) for the at least two second random access messages from the at least one cell.

18. The method of claim 17 , wherein the UE monitors for each PDSCH based on a same beam as a control channel scheduling a respective PDSCH.

19. The method of claim 17 , wherein the UE monitors for a PDSCH from the multiple PDSCHs based on a different beam than a corresponding control channel scheduling the PDSCH, wherein the different beam is configured by DCI in the corresponding control channel.

20. The method of claim 17 , further comprising:

determining a resource allocation for a first PDSCH of the multiple PDSCHs from a control channel for a second PDSCH, wherein each control channel for the at least two second random access messages carries resource allocation information for the multiple PDSCHs for the at least two second random access messages.

21. The method of claim 17 , wherein each of the multiple PDSCHs carry uplink grant information for a plurality of third random access messages.

22. An apparatus for wireless communication at a user equipment (UE), comprising:

a memory; and

at least one processor coupled to the memory and configured to:

transmit at least two first random access messages (Msg 1) directed to different transmission reception points (TRPs) of multiple TRPs for at least one cell using different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; and

monitor, after transmission of the at least two first random access messages, for at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell based on the different time resources or the different frequency resources for the multiple TRPs.

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

receiving, from a user equipment (UE), at least two first random access messages (Msg 1) directed to different transmission reception points (TRPs) of multiple TRPs for at least one cell based on different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; and

transmitting, to the UE and after receiving the at least two first random access messages, at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell based on the different time resources or the different frequency resources for the multiple TRPs.

24. The method of claim 23 , wherein the different resources further comprise different spatial resources in addition to the one or more of the different frequency resources, or the different time resources.

25. The method of claim 23 , wherein each of the at least two first random access messages include a preamble, and wherein the base station receives the at least two first random access messages from the UE using a number of reception beams for reference signals corresponding to a number of transmitting beams from the UE during a corresponding number of allocated random access occasions, each random access occasion being associated with a reference signal.

26. The method of claim 25 , wherein the reference signals include at least one of a synchronization signal block (SSB) or a channel state information-reference signal (CSI-RS) from a cell, wherein the reference signals are transmitted using the multiple TRPs.

27. The method of claim 25 , wherein the at least two first random access messages are time division multiplexed on the number of transmitting beams or frequency division multiplexed on the number of transmitting beams.

28. The method of claim 25 , wherein the base station receives a first preamble using a first beam from a first random access beam pool and receives a second preamble using a second beam from a second random access beam pool,

wherein the first preamble is received using a first receive beam selected from a first random access resource candidate beam pool at a cell, and

wherein the second preamble is received using a second receive beam selected from a second random access resource candidate beam pool at the cell, the first receive beam being for a first transmission reception point (TRP) of the cell, and the second receive beam being for a second TRP of the cell.

29. The method of claim 28 , further comprising:

transmitting, to the UE, an indication of a random access beam pool index per reference signal from the at least one cell.

30. An apparatus for wireless communication at a base station, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

receive, from a user equipment (UE), at least two first random access messages (Msg 1) directed to different transmission reception points (TRPs) of multiple TRPs for of at least one cell based on different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; and

transmit, to the UE and after reception of the at least two first random access messages, at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell based on the different time resources or the different frequency resources for the multiple TRPs.