A control method, capable of reducing the call dropped rate of a mobile station in a wireless communication system, includes monitoring receiving power levels of a plurality of neighbor cells of the wireless communication system according to an information of a serving cell of the wireless communication system; and if the Base Station Identification Codes (BSICs) of the six neighbor cells corresponding to the six strongest receiving power levels are known, and if the BSIC of at least one neighbor cell corresponding to at least one receiving power level other than the six strongest ones is unknown, performing frequency correction and synchronization of the mobile station with respect to the at least one neighbor cell's Broadcast Control Channel (BCCH) to decode the at least one neighbor cell's BSIC.