A radio access network apparatus is disclosed. The apparatus communicates with a mobile station using a dedicated uplink channel, a downlink shared data channel, and a downlink signaling control channel. The apparatus includes a dedicated uplink channel allocating unit which allocates, to a mobile station starting or restarting communications, on a downlink shared data channel, a dedicated uplink channel to be used by the mobile station; a dedicated channel reception detecting unit which detects, on the allocated dedicated uplink channel, a reception of an uplink transmission from the mobile station; and a downlink transmitting unit which, when the dedicated channel reception of the mobile station is detected, transmits a response to the mobile station using the downlink shared data channel and the downlink signaling control channel.