Research On Mobile Location Management Scheme In Personal Communication Network

Future wireless personal communication network (PCN) will support inter-network roaming between different access networks and core network for higher density and mobility users that will lead to large quantities of system resources consuming. It is significant in mobile computing that rational, effective and optimized mobility management schemes are conceived and their algorithms are proved to be feasible according to some strict theories. So it is very important to optimize the current location management schemes to achieve efficiency.The existing location management strategies such as HLR/VLR have to update the HLR of mobile users frequently when they cross the boundary of a LA, therefore, system performance is reduced and system resource is over consumed. So a two-level pointer forwarding strategy with thresholds is proposed. In this scheme, a part of mobile users in VLRs are selected as the MAs (Mobile Agents). A first level pointer is built between MAs, and a second level pointer is built between MAs and VLRs. Thresholds are set for the two-level pointers. Comparing the cost of the scheme proposed with that of the per-user forwarding scheme, result shows the scheme proposed outperforms the others by choosing two suitable thresholds. At the same time, one of the advantages of our scheme is that though it may have a long pointer chain without increasing the call finding delay.Using the advantage of the Cache scheme, a kind of Cache combines forwarding pointers mobility management scheme (called CCF scheme) is proposed in this paper, which exploits a user's movement and call locality. Even if the Cache information is not up-to-date, the called mobile user can be found by tracing forwarding pointers starting from that VLR pointed in the Cache instead of querying the HLR. Therefore, this scheme can effectively reduce the access to the HLR and the signaling traffic in the location management. Analytic results show that, the proposed scheme outperforms other schemes when a user's CMR is high or the signaling traffic to the HLR is heavy.For the future PCS network adopts smaller cells to accommodate continuously growing population of subscribers, which results in frequent location update and consequently higher signaling cost. In this paper, a ring removal movement-based location update scheme with a selective paging is proposed. This location update schemereduces the location updates by removing the ring formed in terminal's movement path. Numerical results show that the proposed movement-based update scheme provides a better performance than the improved movement-based registration (IMBR) scheme when the terminal's call-to-mobility ratio is small.At last, the thesis is concluded and future work is proposed.