UE Transmission Antenna Selection
This is a feature supported by Rel 9. It is a feature that enable UE to select between Antenna port 0 and 1 when it support multiple Tx Antenna.
UE notifies Network via ue-TxAntennaSelectionSupported in UE Capability Information message on whether it support this function or not.
Network notifies UE (when UE support this feature) via ue-TransmitAntennaSelection on how UE is supposed to apply this fuction.
According to 36.213 8.7 UE transmit antenna selection,
A UE configured with transmit antenna selection for a serving cell is not expected to
• be configured with more than one antenna port for any uplink physical channel or signal for any configured
serving cell, or
• be configured with trigger type 1 SRS transmission on any configured serving cell, or
• be configured with simultaneous PUCCH and PUSCH transmission, or
• be configured with demodulation reference signal for PUSCH with OCC for any configured serving cell
• receive DCI Format 0 indicating uplink resource allocation type 1 for any serving cell.
When this is configured by high layer, network notifies UE on which antenna it should use for each transmission by masking CRC field of PDCCH (DCI) as shown below (See 36.212 18.104.22.168 CRC attachment for further details)