A method of compressing uplink control information in a wireless communication system where an MSS scans neighbor BSs upon request from a serving BS and transmits neighbor BS information to the serving BS. In the method, the serving BS broadcasts a neighbor advertisement message including the BS ID of at least one neighbor BS about which the serving BS wants to acquire information, and the BS ID of the at least one neighbor BS. The MSS then scans a channel from the at least one neighbor BS and transmits a scanning result along with a BS index of the at least one neighbor BS to the serving BS.