Patent ID: 8625540

Claim:
A mobile communication system comprising: a mobile station device, a first base station device configured to manage a serving cell of the mobile station device, and a second base station device configured to manage a cell of a handover destination for the mobile station device, wherein the first base station device notifies the mobile station device of first cell identification information of the second base station device to cause the mobile station device to start to receive second cell identification information used to determine a cell reported by the mobile station device as the cell of the handover destination, in a case that the cell of the handover destination for the mobile station device cannot be determined due to conflict of the first cell identification information of cell managed by the second base station device, the first cell identification information representing a combination of radio signals of a synchronization channel of the second base station device and being included in a measurement report message transmitted by the mobile station device, and the mobile station device receives the second cell identification information from the second base station device notified by the first cell identification information, and transmits, to the first base station, the measurement report message including the first cell identification information, and the second cell identification information received from the second base station device.