Section: 6.3.4.4 Precoding for spatial multiplexing using antenna ports with UE-specific reference signals
Content: Precoding for spatial multiplexing using antenna ports with UE-specific reference signals is only used in combination with layer mapping for spatial multiplexing as described in clause 6.3.3.2. Spatial multiplexing using antenna ports with UE-specific reference signals supports up to eight antenna ports. If the higher-layer parameter dmrs-tableAlt is set to TRUE and the set of antenna ports is used for two layers transmission, the precoding operation for transmission on the two antenna ports is defined by where , . If the higher-layer parameter semiOpenLoop is set to TRUE for subframe PDSCH or the higher-layer parameter semiOpenLoop-STTI is set to TRUE for slot/subslot PDSCH and the set of antenna ports is used for rank=2 transmission, the precoding operation for transmission on the two antenna ports is defined by where and . If the number of codewords is two and the DCI associated with the scheduled PDSCH is of Format 2D and the 'PDSCH RE Mapping and Quasi-Co-Location indicator' field in the DCI indicates a higher-layer configured PDSCH-RE-MappingQCL containing two sets of parameters, the precoding operation for transmission on antenna ports is defined by where , and set of antenna ports used is given by Table 6.3.4.4-1. Table 6.3.4.4-1: Layer-to-port mapping for two-codeword transmission when PDSCH-RE-MappingQCL contains two sets of parameters Otherwise, the set of antenna ports used is and the precoding operation for transmission on antenna ports is defined by where , .