Historical based location management strategies for PCS networks

Abstract

Due to the current popularity of wireless communication, personal communication service networks have attracted a lot of attention. As mobile terminals (MTs) in such networks have the ability to communicate on the move, location management (LM) is a critical issue that should be handled carefully. Managing MTs locations is to simultaneously perform two main operations, which are; location update and paging. A good LM strategy maintains both operations with the minimum time and signaling penalties. Although several LM strategies have been introduced, they still suffer from several drawbacks. This paper introduces three novel LM strategies, which are; historical based location management (HBLM), direction based location management (DBLM) and trajectory based location management (TBLM). TBLM strategy is based on geographical position of MTs, while HBLM and DBLM are based on geographical position of MTs as well as time aspects. Visited locations are saved in MT's internal cache in the form of cell identifier as well as the corresponding time interval. Location tracking is fully supervised by the MT's current visitor location register (VLR). On the other hand, the collected location information in MT's cache is sent to VLR when MT passed through a previously defined number of cells or when a previously defined number of time periods has elapsed. In HBLM, paging is done according to the historical movements saved in VLR, while DBLM takes also MT's movement direction into consideration while in TBLM, paging is done according to the historical trajectories that MTs are used to follow. Experimental results have shown that the proposed LM strategies significantly improve MTs' tracking process as they introduce the minimum signaling penalty (for paging and registration) with an acceptable paging time delay compared with recent LM strategies.