In 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 two-level pointer for location update and the profile-based cache for call delivery. Location 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.

This paper proposes a new selective aperiodic checkpointing approach for VLR (Visitor Location Register) failure restoration in wireless mobile networks. In this approach, the VLR data are backed up in the non-volatile storage whenever the location update counter for that VLR exceeds the pre-determined threshold. It restores the backed up VLR data after the failure of the VLR and sends location confirmation request messages only to the selected Registration Areas (RAs) whose information is updated between the time period of back up and failure of the VLR. This is necessary as this information is obsolete in the backed up VLR for this reason and needs to be updated in the restored VLR. However, previous work on aggressive restoration based on periodic and aperiodic checkpointing also provide solutions for VLR database failure recovery. But these solutions are not feasible as they broadcast the location confirmation request messages to the RAs whose location information is found to be obsolete during the restoration. The analytical model and experimental results also show that the proposed method outperforms other previous approaches as it selectively sends the location confirmation request messages instead of broadcasting to the RAs during VLR restoration process.