Patent ID: 6973311

Claim:
A method of relocating a serving radio network controller (RNC) in a radio telecommunication system, when a first RNC detects a user equipment (UE) move out of service area of the first RNC, to switch the first RNC which is assigning radio and network resources to the UE to a second RNC replacing the first RNC for assigning radio and network resources to the UE continuously, said radio telecommunication system also comprising a core network (CN) which comprises a plurality of serving GPRS support node (SGSN), the first RNC being coupled to a first SGSN of the plurality of SGSNs, the second RNC being coupled to a second SGSN of the plurality of SGSNs, said method comprising the steps of: at the first RNC, sending a Relocation Required Message to the first SGSN, the Relocation Required Message comprising a target ID which represents the second RNC; at the first SGSN, based on the target ID of the Relocation Required Message, determining whether the first SGSN and the second SGSN are the same SGSN, when YES, performing the following steps: at the first SGSN, sending a Relocation Request Message to the second RNC; according to the Relocation Request Message, the second RNC assigning radio and network resources to the UE; at the second RNC, sending a Relocation Request Acknowledge Message to the first SGSN; at the CN, based on the Relocation Request Acknowledge Message, switching a first routing path between the first RNC and the first SGSN to a second routing path between the second RNC and the first SGSN; at the first SGSN, sending a Relocation Command Message to the first RNC; and at the first RNC, sending a Relocation Commit Message to the second RNC.