When a downlink transmission is performed in the handover state in a mobile communication system having a mobile station, base stations and a base station controller, user data from the base station controller is transmitted from a first base station to the mobile station and error correction code for the user data from the base station controller is transmitted from a second base station to the mobile station. The mobile station subjects the received user data to error correction processing using the received error correction code and decodes the user data. Also, at the time of an uplink transmission in the handover state, user data and error correction code are transmitted from the mobile station to the base station controller via separate transmission paths.