HANDOVER METHOD FROM THIRD GENERATION DIRECT SEQUENCE SYSTEM TO SECOND GENERATION OR THIRD GENERATION SYNCHRONIZATION SYSTEM

摘要

PURPOSE: A handover method from a third generation(3G) direct sequence(DS) system to a second generation(2G) or a third generation(3G) synchronization system is provided to effectively support a handover in an operation harmonization group(OHG) environment obtaining a system synchronization required for handover from 3G DS system cell to 2G or 3G synchronization system cell and identifying a target base station. CONSTITUTION: A user terminal(UE) reports an intensity of a receiving power to a radio network controller(RNC) periodically or upon request(2-1). The RNC determines whether a handover is to be performed and a type of the handover(2-2). In case of handover to a 2G synchronization system, the RNC broadcasts information on an adjacent cell(2-3). The user terminal(UE) obtains a system synchronization of the adjacent 2G cell by using a compression mode of a 3G DS of the system information of the adjacent 2G cell(2-4). The user terminal(E) informs the RNC of the system information of the adjacent cell obtained by synchronization, to request a channel establishment to a target base station(2-5). The RNC completes a channel establishing to the target base station and transmits a handover instruction to the user terminal(UE)(2-6). The UE informs the RNC of the response to the handover instruction, that is initiation of handover(2-7). When handover is completed, the UE informs the target base station of it(2-8), and the target base station informs an MSC that handover has been completed for a radio interval(2-9). The MSC requests the FNC to release a resource allocated to a call(2-10). The RNC informs the MSC that the resource has been released for the corresponding call(2-11).