A control station serving as a base-station control device that issues an operation instruction to each of base stations in a wireless communication system in which a plurality of base stations perform transmission at the same time and the same frequency, wherein a frequency offset of a reception signal from a mobile station that is detected by each of the base stations is collected, and a phase rotation amount that is a rotation amount when the base stations rotate a phase of a transmission signal is determined for each of the base stations so that frequency offsets of the respective transmission signals having been subjected to phase rotation by the respective base stations are the same.