Patent ID: 8804630

Claim:
A radio base station comprising: a transmitter configured to designate, with respect to a mobile station, a random access preamble when the radio base station has downlink user data to be transmitted to the mobile station; and a receiver configured to receive the designated random access preamble from the mobile station, wherein the transmitter transmits, to the mobile station, timing adjustment information prepared based on a result of reception of the random access preamble, and allocation information about an uplink radio resource allocated to the mobile station, when the mobile station does not have control data to be transmitted, the receiver receives a synchronization completion report from the mobile station by using the uplink radio resource specified by the allocation information, and when the mobile station has the control data, the synchronization completion report is omitted and the receiver receives the control data from the mobile station by using the uplink radio resource specified by the allocation information.