Patent ID: 8611377

Claim:
A mobile communication system provided with a mobile station device and a base station device, the mobile communication system comprising: the mobile station device comprising: a downlink synchronization error detecting portion configured to detect an occurrence of a downlink synchronization error from a measurement result of a transmission signal received from the base station device; a synchronization monitoring portion configured to generate a random access channel based on both a downlink synchronization state and an uplink synchronization state of the mobile station device, the downlink synchronization state transits based on information regarding the detection of the downlink synchronization error and a timer, and, the uplink synchronization state transits based on received information regarding an uplink timing adjustment, the generated random access channel including information regarding the detected downlink synchronization error in a case that a time regarding the uplink timing adjustment is elapsed; and a downlink synchronization error notifying portion configured to transmit a notification of the detected occurrence of the downlink synchronization error, using the random access channel, to the base station device, and the base station device comprising: an adaptive control portion configured to receive the random access channel from the mobile station device and perform scheduling based on the occurrence of the downlink synchronization error.