Hierarchical group location tracking for transportation systems in wireless personal communication networks

Abstract

A hierarchical group location tracking (HGLT) based on group location tracking and hierarchical location update is proposed to reduce the location management cost for terrestrial transportation systems (TSs) in personal communication networks. A global group location update (GGLU) and a local group location update (LGLU) are performed to provide an accurate position for a user. The GGLU informs a virtual visitor location register of the currently camped-on location area and the LGLU informs the serving mobile switching center of the currently camped-on cell. Although the LGLU is done each time a TS moves into a new cell, it causes small increment in the signaling cost due to localized updates and group updates compared with the previous group location tracking scheme. The proposed scheme significantly reduces the paging cost because the scheme pages only a camped-on cell using the LGLU information. Compared with the previous schemes, the HGLT reduces the location management cost, and it is more efficient as the cost for paging a cell increases.