SYNCHRONIZATION REFERENCE RESELECTION PROCEDURE DESIGN FOR V2X COMMUNICATION

摘要

Currently, in legacy LTE, the UE will choose PCell (RRC_CONNECTD) or the serving cell (RRC_IDLE) as synchronous reference when V2X sidelink communication is out of coverage on the concerned frequency. In NR, considering the EN-DC, NE-DC OR NR-DC deployment, it's not necessary for the UE to always choose PCell as the synchronous reference. One option is UE will always choose gNB as the synchronous reference. When both PCell and PSCell are gNBs, UE could choose PCell as the synchronous reference. Another option is UE will choose PCell or PSCell based on their RSRP values. The third option is that the network can signal a RSRP threshold. When PCell and PSCell's RSRP will be higher than this threshold, the UE will at first choose gNB as synchronous reference because gNB can give better timing to UE. In other case, the UE can choose synchronous reference based on PCell and PSCell's RSRP value.