Mobile communications system, radio network controller, and active set control method

A radio network controller which is connected to each of base stations, and which has an active set table indicating a state of an active set for each of mobile terminals, the active set including a list of cells in each of which a radio channel between a mobile terminal and a base station is set up when the mobile terminal performs handover between cells which are formed by the base stations,

• wherein the radio network controller deletes a cell from the active set of the mobile terminal by a request to release a radio channel corresponding to the cell from any one of the mobile terminals and the base stations, and then, upon receiving a setup request of the radio channel, the radio network controller performs processing for any of responding and ignoring the setup request based on an elapsed time after the last deletion of the cell.

An active set control method of controlling, in a radio network controller, addition and deletion of a cell to and from an active set, which is a list of cells in each of which a radio channel between a mobile terminal and a base station is set up when the mobile terminal performs handover between cells which are formed by the base stations, the active set control method comprising:

• a cell addition control step of deleting a cell corresponding to a radio channel from the active set of the mobile terminal by a request to release the radio channel corresponding to the cell from any one of the mobile terminal and the base stations, and receiving a set up request of the radio channel, and performing processing for any of responding and ignoring the setup request based on an elapsed time after the last deletion of the cell from the active set.

An active set control system of controlling, in a radio network controller, addition and deletion of a cell to and from an active set, the system comprising:

• means for modifying the active set, which includes a list of cells in each of which a radio channel between a mobile terminal and a base station is set up when the mobile terminal performs handover between cells which are formed by the base stations;
• and
• cell addition control means for deleting a cell corresponding to a radio channel from the active set of the mobile terminal by a request to release the radio channel corresponding to the cell from any one of the mobile terminal and the base stations, and for receiving a set up request of the radio channel, and for performing processing for any of responding to and ignoring the setup request based on an elapsed time after the last deletion of the cell from the active set.