PDCP DUPLICATION ENHANCEMENTS

Methods, systems, apparatus, and computer programs, for selecting radio link control (RLC) entities to transmit packet data convergence protocol (PDCP) control protocol data unit (PDU). In one aspect, the method includes actions of accessing, by a device in a wireless communication system, data representing an index of RLC entities of a data radio bearer (DRB)/PDCP entity and RLC activation state information, the activation state information indicating whether one or more RLC entities of the DRB/PDCP entity in the index of RLC entities is activated or deactivated, selecting, by the device in the wireless communication system, a subset of the RLC entities of the DRB/PDCP entity based on an index position in the index and the activation state information for each of the RLC entities, and using the selected subset of RLC entities of the DRB/PDCP entity to transmit the PDCP Control PDU.