Patent ID: 6961566

Claim:
A frequency search method that determines a frequency to be used by a mobile station for communication in a mobile communication system, comprising: one or a plurality of subset-frequency search procedures each of which is configured to search the frequency to be used by the mobile station for communication from a subset of frequencies selected, based on predetermined criteria, out of all the frequencies that are allocated for the mobile communications system, each of the procedures being performed in a predetermined priority sequence assigned to each of the procedures until a frequency to be used is determined, and an all-frequency search procedure that searches a frequency to be used by the mobile station from all the frequencies that are allocated for the mobile communications system, which is performed when the subset-frequency search procedures for the selected frequencies fail, wherein said one or the plurality of the subset-freciuency search procedures are repeated if no frequencies are determined as the frequency to be used in the all-frequency search procedure, and the all-frequency search procedure is performed when a predetermined timing condition is satisfied while the subset-frequency search procedures are repeated without determining the frequency to be used.