A New Location Caching with Fixed Local Anchor for Reducing Overall Location Management Cost in Wireless Mobile Networks

The proposed approach in this paper selects a fixed Visitor Location Register (VLR) as a Fixed Local Anchor (FLA) for each group of Registration Areas (RAs). During call delivery process, the calling VLR/FLA caches are updated with the called Mobile Terminal’s (MT’s) location information and the called VLR and FLA caches are updated with the calling MT’s location information. Furthermore, the FLA and the old VLR caches are updated with MT’s new location information during inter-RA handoff as a part of informing this to the FLA of that region. But for another case, it updates the new FLA, old FLA, and old VLR caches with new location information together with directly informing this to the Home Location Register (HLR). This location caching policy in local anchor strategy maximizes the probability of finding MTs’ location information in caches. As a result, it minimizes the total number of HLR access for finding MT’s location information prior to deliver a call. So, it significantly reduces the total location management cost in terms of location registration cost and call delivery cost. The analytical and experimental results also demonstrate that the proposed method outperforms all other previous methods regardless of the MT’s calling and mobility pattern.