Multi-transmit receive point demodulation reference signal port identification

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

receiving, from a transmit receive point (TRP), a downlink control information (DCI) that includes a transmission configuration indication (TCI) field;

determining that the TCI field specifies a quantity of two or more TCI states;

identifying, based at least in part on the determining, a multi-TRP demodulation reference signal (DMRS) port group configuration included in a multi-TRP DMRS port group configuration data structure comprising information identifying the multi-TRP DMRS port group configuration and a plurality of DMRS port groups,

wherein the plurality of DMRS port groups include a first DMRS port group, associated with the TRP, and a second DRMS port group associated with another TRP; and

performing, based at least in part on the first DMRS port group, a channel estimation for a downlink of a wireless communication link between the UE and the TRP.

2. The method of claim 1 , further comprising:

performing, based at least in part on the first DMRS port group, another channel estimation for another downlink of another wireless communication link between the UE and another TRP.

3. The method of claim 1 , wherein the quantity of two or more TCI states specify the plurality of DMRS port groups; and

wherein the UE is communicatively coupled to the other TRP.

4. The method of claim 3 , wherein the first DMRS port group is quasi-co-located with a first reference signal (RS) set associated with the TRP;

wherein the second DMRS port group is quasi-co-located with a second RS set associated with the other TRP; and

wherein one or more first DMRS ports, included in the first DMRS port group, and one or more second DMRS ports, included in the second DMRS port group, are not included in a same DMRS code division multiplexing (CDM) group.

5. The method of claim 3 , wherein the first DMRS port group is ordered before the second DMRS port group in the multi-TRP DMRS port group configuration; and

wherein the second DMRS port group is ordered before the first DMRS port group in another multi-TRP DMRS port group configuration included in the multi-TRP DMRS port group configuration data structure.

6. The method of claim 3 , wherein the TCI field specifies an order of the first DMRS port group and the second DMRS port group in the multi-TRP DMRS port group configuration.

7. The method of claim 1 , further comprising:

identifying the multi-TRP DMRS port group configuration data structure based at least in part on determining that the TCI field specifies a quantity of two or more TCI states.

8. The method of claim 1 , wherein identifying the multi-TRP DMRS port group configuration comprises:

identifying the multi-TRP DMRS port group configuration based at least in part on a multi-TRP DMRS port group configuration index identified in the DCI.

9. The method of claim 1 , wherein the first DMRS port group includes one or more first DMRS ports associated with the TRP; and

wherein the second DMRS port group includes one or more second DMRS ports associated with the other TRP.

10. The method of claim 9 , wherein each DMRS port, of the one or more first DMRS ports, is associated with a respective downlink layer transmitted by the TRP.

11. The method of claim 1 , wherein the downlink, of the wireless communication link between the UE and the TRP, comprises a plurality of downlink transmission layers; and

wherein performing the channel estimation for the downlink of the wireless communication link between the UE and the TRP comprises:

identifying the plurality of downlink transmission layers based at least in part on the multi-TRP DMRS port group configuration data structure, and

performing the channel estimation for each downlink transmission layer of the plurality of downlink transmission layers.

12. The method of claim 11 , wherein each downlink transmission layer, of the plurality of downlink transmission layers, is associated with a respective DMRS port of the first DMRS port group.

13. A method of wireless communication performed by a transmit receive point (TRP), comprising:

assigning, to a first user equipment (UE), a first multi-TRP demodulation reference signal (DMRS) port group configuration, specified in a multi-TRP DMRS port group configuration data structure, that includes information identifying a plurality of multi-TRP DMRS port group configurations, including the first multi-TRP DMRS port group configuration, and a plurality of DMRS port groups, based at least in part on the first UE being configured to receive multi-TRP communications,

wherein the plurality of DMRS port groups include a first DMRS port group, associated with the TRP, and a second DRMS port group associated with another TRP; and

assigning, to a second UE, one of:

a second multi-TRP DMRS port group configuration of the plurality of multi-TRP DMRS port group configurations, or

a single-TRP DMRS port group configuration specified in a single-TRP DMRS port group configuration data structure.

14. The method of claim 13 , wherein assigning one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE comprises:

assigning one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE based at least in part on:

a codeword configuration associated with the TRP,

a front-loaded OFDM symbol configuration associated with the TRP, or

a DMRS type associated with the TRP.

15. The method of claim 13 , wherein assigning one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE comprises:

assigning one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE based at least in part on whether the second UE is configured to receive the multi-TRP communications or single-TRP communications.

16. The method of claim 13 , wherein the first multi-TRP DMRS port group configuration and the second multi-TRP DMRS port group configuration are different multi-TRP DMRS port group configurations of the plurality of multi-TRP DMRS configurations.

17. A user equipment (UE) for wireless communication, comprising:

a memory; and

one or more processors coupled to the memory, the memory and the one or more processors configured to:

receive, from a transmit receive point (TRP), a downlink control information (DCI) that includes a transmission configuration indication (TCI) field;

determine that the TCI field specifies a quantity of two or more TCI states;

identify, based at least in part on the determining, a multi-TRP demodulation reference signal (DMRS) port group configuration included in a multi-TRP DMRS port group configuration data structure comprising information identifying the multi-TRP DMRS port group configuration and a plurality of DMRS port groups,

wherein the plurality of DMRS port groups include a first DMRS port group, associated with the TRP, and a second DRMS port group associated with another TRP; and

perform, based at least in part on the first DMRS port group, a channel estimation for a downlink of a wireless communication link between the UE and the TRP.

18. The UE of claim 17 , wherein the TCI field specifies a quantity of two TCI states that specify the plurality of DMRS port groups; and

wherein the UE is communicatively connected to the other TRP.

19. The UE of claim 18 , wherein the first DMRS port group is quasi-co-located with a first reference signal (RS) set associated with the TRP;

wherein the second DMRS port group is quasi-co-located with a second RS set associated with the other TRP; and

wherein one or more first DMRS ports, included in the first DMRS port group, and one or more second DMRS ports, included in the second DMRS port group, are not included in a same DMRS code division multiplexing (CDM) group.

20. The UE of claim 18 , wherein the first DMRS port group is ordered before the second DMRS port group in the multi-TRP DMRS port group configuration; and

wherein the second DMRS port group is ordered before the first DMRS port group in another multi-TRP DMRS port group configuration included in the multi-TRP DMRS port group configuration data structure.

21. The UE of claim 18 , wherein the TCI field specifies an order of the first DMRS port group and the second DMRS port group in the multi-TRP DMRS port group configuration.

22. The UE of claim 17 , wherein the one or more processors are further configured to:

identify the multi-TRP DMRS port group configuration data structure based at least in part on determining that the TCI field specifies a quantity of two or more TCI states.

23. The UE of claim 17 , wherein the one or more processors, when identifying the multi-TRP DMRS port group configuration, are configured to:

identify the multi-TRP DMRS port group configuration based at least in part on a multi-TRP DMRS port group configuration index identified in the DCI.

24. The UE of claim 17 , wherein the first DMRS port group includes one or more first DMRS ports associated with the TRP; and

wherein the second DMRS port group includes one or more second DMRS ports associated with the other TRP.

25. The UE of claim 17 , wherein the downlink, of the wireless communication link between the UE and the TRP, comprises a plurality of downlink transmission layers; and

wherein the one or more processors, when performing the channel estimation for the downlink of the wireless communication link between the UE and the TRP are configured to:

identify the plurality of downlink transmission layers based at least in part on the multi-TRP DMRS port group configuration data structure, and

perform the channel estimation for each downlink transmission layer of the plurality of downlink transmission layers.

26. The UE of claim 25 , wherein each downlink transmission layer, of the plurality of downlink transmission layers, is associated with a respective DMRS port of the first DMRS port group.

27. A transmit receive point (TRP) for wireless communication, comprising:

a memory; and

one or more processors coupled to the memory, the memory and the one or more processors configured to:

assign, to a first user equipment (UE), a first multi-TRP demodulation reference signal (DMRS) port group configuration, specified in a multi-TRP DMRS port group configuration data structure, that includes information identifying a plurality of multi-TRP DMRS port group configurations, including the first multi-TRP DMRS port group configuration, and a plurality of DMRS port groups, based at least in part on the first UE being configured to receive multi-TRP communications,

wherein the plurality of DMRS port groups include a first DMRS port group, associated with the TRP, and a second DRMS port group associated with another TRP; and

assign, to a second UE, one of:

a second multi-TRP DMRS port group configuration of the plurality of multi-TRP DMRS port group configurations, or

a single-TRP DMRS port group configuration specified in a single-TRP DMRS port group configuration data structure.

28. The TRP of claim 27 , wherein the one or more processors, when assigning one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE, are configured to:

assign one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE based at least in part on:

a codeword configuration associated with the TRP,

a front-loaded OFDM symbol configuration associated with the TRP, or

a DMRS type associated with the TRP.

29. The TRP of claim 27 , wherein the one or more processors, when assigning one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE, are configured to:

assign one of the second multi-TRP DMRS port group configuration or the single-TRP DMRS port group configuration to the second UE based at least in part on whether the second UE is configured to receive the multi-TRP communications or single-TRP communications.

30. The TRP of claim 27 , wherein the first multi-TRP DMRS port group configuration and the second multi-TRP DMRS port group configuration are different multi-TRP DMRS port group configurations of the plurality of multi-TRP DMRS port group configurations.