Patent ID: 8055263

Claim:
A method performed by a radio network controller (RNC) for controlling a change in base station performing scheduling a packet data service of a terminal from a source base station to a target base station when a serving cell for the packet data service changes from a source cell controlled by the source base station to a target cell controlled by the target base station, the method comprising: receiving from the terminal information indicating that the target cell should be added to an active set; in response to the information indicating that the target cell should be added to the active set and before receiving from the terminal any information indicating that the target cell has become a best cell, preparing the target base station and the terminal to configure for a potential packet data service served by the target base station, the preparing operation including: transmitting to the target base station configuration information for the potential packet data service, so as to allow the target base station to configure for the potential packet data service; transmitting to the terminal configuration information for the potential packet data service and a request message requesting the terminal to update the active set and allowing the terminal to establish a radio link to the target base station; and receiving from the terminal a response message indicating a completion of setting of configuration for the potential packet data service using the configuration information for the packet data service transmitted to the terminal; receiving from the terminal information on a change in best cell, the information on the change in best cell indicating that the target cell is a best cell; and in response to the information on the change in best cell, committing a change in serving cell for the packet data service of the terminal from the source cell to the target cell, the committing operation including: transmitting to the target base station a message so as to allow the target base station to perform packet data service scheduling for the terminal based on the configuration information for the potential packet data service previously transmitted to the target base station; and transmitting to the source base station a message so as to allow the source base station to stop packet data service scheduling for the terminal.