The present invention is directed to a handover method, a base station, and a mobile station for a CDMA mobile communication system, to improve the efficiency of inter-frequency handover. Handover is achieved between a mobile station and distributed base stations and the like. The base stations have different traffic channel frequencies. In a normal mode, a signal unit transmitted through a traffic channel consists of four frames. In a compression mode, the base station temporally compresses two normal frames into a single frame period and then transmits the frames twice through the traffic channel. The mobile station switches the reception frequency of a present traffic channel and the reception frequency of a perch channel of the destination base station at intervals of two normal-mode frames at the head of each frame received from the perch channel. The mobile station then restores frames received from the traffic channel in the compression mode to the original frames and processes them. At the same time, the mobile station extracts a system frame number from two frames received from the perch channel.