Method for performing handover between systems in mobile telecommunication system

GSM (Global System for Mobile communication) / GPRS (General Packet Radio Service) technology and UMTS (Universal Mobile Telecommunications System) technology by communicating all possible dual-mode mobile terminal is a GSM / GPRS to by the communication support to BSS (Base Station Subsystem) region on a dedicated channel a connection and communication to perform that during the UMTS to by the communication support to UTRAN (UMTS Terrestrial Radio Access Network) area, to the mobile as by generating a handover between the systems to perform the method in method, the as the inter-system handover command to the UTRAN from the BSS receives the mobile terminal the dual mode GSM / GPRS by a sublayer RR (Radio Resource) within a GSM / GPRS network layer in the mobile terminal / GRR (GPRS-RR) requires data link pending GSM / to a GPRS data link layer, and to pass the right to the GSM / GPRS physical channel release to the request to the GSM / GPRS physical layer, as well sub-layer within the UMTS network layer in the mobile terminal RRC (Radio Resource Control) the method comprising the steps of: determining whether the UTRAN successful intersystem handover process of delivering a command and the mobile terminal within the by the RRC request the UMTS physical channel configuration in the UMTS the physical layer and the UMTS physical layer configuration the UMTS physical layer to a, transmitting the UMTS physical If successful in the layer configuration that the inter-system handover procedure by the mobile station within the configuration Kane require UMTS data link to the UMTS data link layer by the RRC, and addition UTRAN has been successfully completed by the UTRAN through a UMTS channel is to process and requires a GSM / GPRS resources released by the inner RRC, the mobile station to within the RR / GRR, the mobile station in GSM / GPRS physical layer and the GSM / GPRS data link layer consists of a process which causes a reset to the default configuration. The intersystem handover, GSM / GPRS, UMTS, inter RAT handover (inter RAT handover)