Location Management Of Mobility Management In Next-Generation Mobile Network

Mobile communication technologies have experienced tremendous growth over the pasttwo decades. The third-generation systems and the beyond third-generation systems providevarious types of services such as voice, circuit/packet data, and multimedia. The growingdensity of subscribers and the need for hand-off and roaming underscore the importance oflocation management. This dissertation focuses on location management in mobile network, covers locationupdate strategy, paging policy and location database design. Several novel strategies havebeen proposed and verified to be effective by both analysis and simulation. A framework forsimulation system is presented as well. To minimum location update and paging costs, this dissertation proposes a dynamicdistance-based location update scheme, including dynamic location size calculation and atwo-step paging policy. Considering about mobile uses' mobility characteristics, asector-based dynamic location area model is presented. Simulation result shows thissector-based dynamic location area model has effectively reduced location update costs. In the 4th section, we propose a novel strategy of correlation boundaries against the twomain problems of location management scheme in cellular networks: Ping-Pong locationupdate effect existing between two location areas and concentration of signals at boundaries.This strategy is able to reduce the Ping-Pong effect effectively and smooth the load ofsignals at boundaries by adding certain cells as expansions of the new location area,whenever a mobile terminal moves into a cell belongs to a new location area. Comparedwith existing strategies, the strategy in this paper is easier to implement and also improvesthe performance greatly. Analysis and simulation results both show the correlationboundaries strategy reduces location update costs by about 25%. In 3G and beyond 3G mobile systems, there is a tendency of combination ofheterogeneous networks, such as traditional mobile network, WLAN, and Ad Hoc. Based onthis idea, this dissertation proposes a new location update scheme for subscribers on an areawhere a large number of fast-moving users need send update information frequently. Thegroup location update scheme in which a group location update is performed by a leadermobile terminal instead of individual update by every normal mobile terminal has been IIIproposed. Mobile terminals (MT) relatively near form a group and select a leader to collectlocation update reports of other MTs and report in groups. We build a stochastic servicesystem model to analyze the group location update scheme and individual location updatescheme in the view of channel access cost. Compared with individual scheme, group updatescheme obviously increases channel capability and system throughput due to a significantreduction in signaling cost per update and the number of location updates. As user mobilityincreases or the number of users in the group increases, the advantage of the group updatescheme improves. We also analyze delay caused by bulk process and give arecommendation for the bulk size choice to get better throughput performance within anacceptable delay. This dissertation's research work also includes location database design in the networkside. An improved scheme for forwarding pointer and local anchor is presented. Using VLRdistributed in different locations as remote backup for central user profile database, thisscheme approaches a distributed copy location database and by defining different workmodes it can describe related users hierarchical location management database.