I am creating this task for the purpose of discussing and tracking. Currently `rxdataF` and `txdataF` has beam index as first dimension to hold logical ports in concurrent beams in a slot. This works fine for analog beamforming where the same beam is applied to the whole OFDM symbol. But this approach does not suite well for digital beamforming where different section of the OFDM symbol can be beamformed separately. The following proposal is an altrenative solution for mapping analog beams to RU ports, and will also work with section based digital beamforming once its implemented. ### Mapping Based on FAPI FAPI v10 has a mechanism to map logical antenna ports of a UE to RU ports. This is done with a combination of PARAM message configuration and PDSCH PDU. The PARAM message defined for this purpose is TLV 0x016E and the PDU message is `spatialStreamIndicesFor-CW-v4` defined in Table 3.4.2.2-7 PDSCH parameters FAPIv4. Current mapping's outcome: ``` ---> DMRS 0 ---> Layer 0 ---> ---> Port 0 ---> RU port 0 UE 0 Beam 0 ---> DMRS 1 ---> Layer 1 ---> ---> Port 1 ---> RU port 1 ---> DMRS 0 ---> Layer 0 ---> ---> Port 0 ---> RU port 2 UE 1 Beam 1 ---> DMRS 1 ---> Layer 1 ---> ---> Port 1 ---> RU port 3 ``` Proposed mapping's outcome: ``` ---> DMRS 0 ---> Layer 0 ---> Port 0 ---> RU port 0 UE 0 ---> DMRS 1 ---> Layer 1 ---> Port 1 ---> RU port 1 ---> DMRS 0 ---> Layer 0 ---> Port 2 ---> RU port 2 UE 1 ---> DMRS 1 ---> Layer 1 ---> Port 3 ---> RU port 3 ``` The beam ID is signalled per logical port for all `dig-BF-Interfaces` ports. FAPI also states that the order of beam IDs is same as the logical ports for a UE and together with `spatialStreamIndicesFor-CW-v4`, the beam IDs can be mapped to RU ports in any order. **Benefits of proposed solution:** - Works for both analogue and digital beamforming - Dynamic mapping of logical ports to RU ports - Follows FAPI specification so easier integration with Aerial