Patent ID: 8676200

Claim:
A mobile communication system comprising: a mobile station device; a first base station device to which an accessible time is set; and a second base station device, wherein one of the mobile station device and the first base station device comprises: a time detector configured to detect that a first time elapses from the time the mobile station device performs position registration to the first base station device, the first time being obtained by subtracting a second time sufficient to complete a handover from the accessible time so as to complete handover before the accessible time expires and prevents call disconnection; and a communication controller configured to, in a case that the time detector detects that the first time elapses from the time the mobile station device performs the position registration to the first base station device, determine, before the accessible time expires, whether or not the mobile station device is in communication with the first base station device, and in a case that the time detector detects that the first time elapses from the time the mobile station device performs the position registration to the first base station device, and the communication controller determines that the mobile station device is in communication with the first base station device, the mobile communication system performs, before the accessible time expires, a handover to switch a communication connection between the mobile station device and the first base station device to a communication connection between the mobile station device and the second base station device.