Base-station system in the wibro mobile communication network having an bs scanning procedure reforming function and controlling method therefore

A WiBro(Wireless Broadband Internet) mobile communication system with a base station scanning procedure improving function and a controlling method thereof are provided to continuously execute a scanning procedure by ignoring an overlapped ranging period if the ranging period is overlapped while the scanning procedure is progressed in a WiBro terminal, thus frequency assignment for the scanning procedure and a waste of execution time are prevented. When a scanning function is set in a WiBro terminal, the terminal loads a signal for demanding assignment of a scanning interval on an MOB-SCN-REQ message, and transmits the message to a serving base station(S1-S5). Though a ranging period is overlapped during the assigned scanning interval period, the terminal ignores the overlapped ranging period, and continuously carries out a scanning procedure(S6).