A mobile communication system includes a condition reporting unit provided in a base station controller and configured to report to a mobile station via the target base station or another base station measurement and report conditions for determining whether to measure and report a reception quality level of a radio signal transmitted from the target base station; a measurement reporting unit provided in the mobile station and configured to measure the reception quality level of the radio signal if the measurement condition is satisfied and to report the measured reception quality level to the base station controller via the target base station or the other base station if the report condition is satisfied; and a radio parameter control unit provided in the base station controller and configured to control a radio parameter of the target base station or the other base station based on the reported reception quality level.