Patent ID: 7962138

Claim:
A method for managing a Routing Area (RA) in a mobile communication system including a mobile station and a network entity that manages mobility of the mobile station, the method comprising the steps of: grouping cells of the mobile communication system into predetermined cell groups by the network entity, wherein each of the predetermined cell groups is a minimum unit for routing area update; determining cell group identifiers of the cell groups by the network entity; determining metric information for determining a shape of the routing area by the network entity; calculating, by the mobile station, a metric value corresponding to a distance by which the mobile station has moved, by using the cell group identifiers; comparing the calculated metric value with the metric information; performing, by the mobile station, the routing area update when the calculated metric value is larger than the metric information; and preventing, by the mobile station, execution of the routing area update when the calculated metric value is less than or equal to the stored metric information, wherein the determined cell group identifiers and the determined metric information are transmitted to the mobile station by the network entity, wherein the metric information includes a one-dimensional metric from a cell group identifier or a two-dimensional metric from the cell group identifier, and wherein when the mobile station has moved, the metric value is calculated by using the cell group identifier of the cell group into which the mobile station has moved and the cell group identifier which was stored in the mobile station before the mobile station moved.