Patent ID: 7383054
Filing Date: 2008-06-03
Classification: H04W

Abstract:
1. A method for selecting a public land mobile network (PLMN), said method being applied in a mobile station, wherein it is suitable for the mobile station to select one among M PLMNs to be a serving PLMN for providing communication services, and M is a natural number, said method comprising the following steps of: (a) receiving N pieces of broadcasting information broadcasted by N base stations respectively and measuring power values of broadcasting information corresponding to the N base stations, wherein N is a natural number; (b) establishing a base station table for recording N sets of information, each set of information being corresponding to one base station among the N base stations, each set of information comprising a measured power value, a base station code, and a PLMN code corresponding to one of the N base stations, the N sets of information being recorded in the base station table in sequence according to the magnitudes of the N power values of broadcasting information, wherein the base station corresponding to the first set of information in the sequence is called as a first base station, the base station corresponding to the second set of information in the sequence is called as a second base station, and the base station corresponding to the Nth set of information in the sequence is called as a Nth base station; (c) setting the initial value of an integer index i as one; (d) selecting an ith priority PLMN as a target PLMN; (e) setting the initial value of an integer index j as one; (f) selecting the jth base station among the N base stations as a candidate base station; (g) according to the PLMN code corresponding to the candidate base station recorded in the base station table, determining whether the PLMN to which the candidate base station belongs is known, if the result of step (g) is YES, then executing step (j), if the result of step (g) is NO, then executing step (h); (h) synchronizing the mobile station with the candidate base station and reading the broadcasting information broadcasted by the candidate base station; (i) updating the value in a PLMN field of the base station table; (j) according to the PLMN code corresponding to the candidate base station recorded in the base station table, determining whether the candidate base station belongs to the target PLMN, if the result of step (j) is YES, then executing step (k), if the result of step (j) is NO, then executing step ( (k) selecting the ith priority PLMN as the serving PLMN that provides communication services to the mobile station; (l) setting j=j+1; (m) determining whether j is larger than N, if the result of step (in) is YES, then executing step (n), if the result of step (in) is NO, then returning back to step (f); (n) setting i=i+1; (o) determining whether i is larger than M, if the result of step (o) is YES, then executing step (p), if the result of step (o) is NO, then returning back to step (d); and (p) terminating said method.