A Profile-Based Two-Level Pointer Forwarding Cache Scheme for Reducing Location Management Cost in Wireless Mobile Networks

Abstract

this paper we propose an efficient location management strategy called the profile#based two#level pointer forwarding cache scheme to improve the overall performance of the wireless mobile networks. It uses the twolevel pointer for location update and the profilebased cache for call delivery. Loca tion update for each Mobile Terminal (MT) is managed by the nearby Visitor Location Register (VLR) until it crosses the threshold of the number movements between Registration Areas (RAs). This reduces the frequency of accessing the remote Home Location Register (HLR) which eventually minimizes the location update cost by distributing its work. On the other hand, a profile of the MT's calling pattern is maintained in HLR and it is copied in the VLR caches from where majority of the calls are generated. These caches are searched first to find out the called MT's location in order to deliver a call. This delivery cost will be reduced if the location information is found in the caches since it does not have to access the remote HLR for searching the location information. The analytical modeling and numerical results show that the proposed method outperforms all other previous methods in terms of network signaling traffic load irrespective of the MTs' mobility and calling pattern. Switching Center (MSC) and the MTs are wirelesscon nected to these BTS. Sometimes the VLR may colocate with the MSC and a group of RAs are interfaced with the Local Signaling Transfer Point (LSTP) following the HLR. An HLR is the centralized database that contains the records of all MTs' profiles together with the location information for the entire network. Similarly, each VLR stores replications of the user profiles of the subscribers currently residing in its corresponding RA. However, there may exist one or more HLRs in the network depending on its configuration. Figure 1 shows the architecture of the wireless mobile networks.