Study And Analysis On Location Management Schemes In Mobile Communication Systems

Mobile communication network is characterized by the user mobility, so, an location management strategy is indispensable to ensure the mobility management performance of the network.A good location management strategy can save network resources, provide fast and stably wireless connection, and guarantee the effective operation of the network.With the 3G (WCDMA, CDMA20001xEV-DO,andTD-CDMA),3.5G (HSDPA),3.75G (HSUPA), and 4G communication networks have appeared around the world, a large number of users will move randomly within the area and be abled to communicate at any time. But frequent location update, inquiry, crowded paging and other message transmission will have a significant signaling load, and it will increase processing time of network systems and reduce the communication capacity in network systems. Therefore, how to configure the location register (centralized or distributed) and how to divide the user's location area is very important to ensure that the called user can be found quickly and accurately when the call arrives, and less wired and wireless resources are consumed at the same time.A two-tier location management database structure and a fixed LA strategy is used for location management in 2G communication system.The fixed LA strategy is that LA size is fixed for each user, and it is determined based on the overall movement and call statistics. It's not the best size for each user, and it can't adapt to the user mobility and call characteristics changing constantly.2G network architecture and location management technologies have been unable to meet the high terminal mobility and personal mobility of users in next generation mobile communication network.The main research objective of this paper is to analyze a location management solution for 3G systems which can improve network performance. The database to store user location information on the network side and the location update and paging strategies and algorithms on access side are analysised in this paper focus on the issues related to mobility. The m-ajor work of this paper is presented as follows:1. A dynamic location update method and the shortest distance priority paging strategy against the shortcomings of fixed LA location update strategy and blanket paging are analyzed, and then, the model including network hypothesis, user mobility and paging modeling are made, the theoretical expression of the total cost of location management is derived using this model. At last, the influence of various parameters on the performance of location management are given, through the analysis it is found that the total cost of location management is a convex function (down) of the movement threshold, and it willl significantly reduced with the increase of call-to-mobility-ratio. The total cost of location management will be decrease without paging delay, and it is not sensitive to the variance of cell dwell time.2. A location management scheme for 3G which have a three-tier database structure against the shortcomings of the database architecture and location management scheme in 2G is proposed. Then, the database system architecture, the location update process and the theoretical model of this scheme are introduced.After that, numerical analysis on it is done, and the conclusion that this scheme for 3G reduce the total location management cost significantly, and the performance of location management is improved effectively are given.