OBTAINING SYSTEM FRAME NUMBER OF TARGET CELL DURING HANDOVER

摘要

A method of obtaining a system frame number (SFN) for handover is provided. A user equipment (UE) receives a handover command from a serving base station in a serving cell. The UE performs downlink synchronization with a target base station. Upon synchronization, the UE determines a radio frame boundary of a target cell. The UE then obtains the system frame number of the target cell based on the radio frame boundary. The UE performs a handover procedure with the target cell by transmitting a random access channel (RACH) preamble to the target base station. The RACH preamble is transmitted over a PRACH resource determined from the SFN without reading SFN information from a physical broadcast channel (PBCH) / broadcast channel (BCH) broadcasted from the target base station. Finally, the UE establishes data connection with the target base station. With this solution, Handover interruption time is reduced by obtaining the SFN before PBCH reading and decoding.