To construct a system abundant in scalability in which the devices are increased or decreased in a minimum unit in accordance with the amount of user data to be processed by dividing the UPE (user plane control equipment) in a radio network controller into the minimum necessary functions, a MAC-d entity only dependent on the individual user data is separated independently from a MAC-c/sh entity so that it may be increased or decreased in accordance with the amount of traffic. Thereby, the unit of increase or decrease can be made not a unit of UPE but a finer unit of MAC-d, resulting in the higher scalability of the system.