Mobile communication method, mobile communication system and radio network controller

A mobile communication system configured to cause a radio base station to notify a mobile station of transmission power control information via a transmission power control channel, the transmission power control information used in the mobile station to control transmission power of uplink user data, the system comprising a radio network controller, wherein

• the radio network controller includes an assignment unit configured to assign a channelization code and a transmission timing for the mobile station on the basis of a status of use of a channelization code and a transmission timing in a sector other than a specific sector when the mobile station sets a radio link with the radio base station in the specific sector, and
• the radio base station is configured to notify the mobile station of the transmission power control information via the transmission power control channel by use of the channelization code and the transmission timing, which are assigned by the assignment unit of the radio network controller, wherein
• the assignment unit is configured to randomly select a first transmission timing usable in a smallest channelization code having a smallest identification number among channelization codes usable in the specific sector, and
• the assignment unit is configured to assign the first transmission timing and the smallest channelization code as the transmission timing and the channelization code for the mobile station in a case where the first transmission timing is usable in all of the channelization codes in all of the sectors under the control of the radio network controller.