Patent ID: 8275392

Claim:
A tracking area assigning method in which a user terminal reports to a tracking area management apparatus a trace along which the user terminal has moved in a mobile communication system and the tracking area management apparatus assigns a tracking area to the user terminal, comprising the steps of: storing, by the user terminal, identifiers of base stations where the user terminal has performed cell selection and times of day at which the user terminal has performed cell selection in an identifier storage unit; reporting, by the user terminal, to the tracking area management apparatus the identifiers and the times of day stored in the identifier storage unit upon communicating with a base station; and comparing, by the tracking area management apparatus, the reported identifiers with a prestored pattern, comparing a time difference between cell selections which is calculated from the reported times of day with a prestored time frame, and assigning the tracking area to the user terminal according to the prestored pattern, when the reported identifiers match the prestored pattern and when the time difference between cell selections is within the prestored time frame.