Research On Network Selection Strategy In Heterogeneous Wireless Integration Networks

Along with the advancement of science and technology, the wireless mobile communication network technology has also been developed rapidly. Different kinds of networks cover the same areas with each other. User terminals equipped with multiple mode interfaces can access various types of network instead of that equipped with single mode interface. The types of services are not only voices or SMS services but also videos, downloads, web service and etc. Because of the heterogeneity of networks, improvement of user terminal equipment, as well as the diversity of service requirements, network selection strategy in heterogeneous wireless integration network is becoming a hot spot in the current researches. How to improve user satisfaction and make full use of network resource is a problem to solve in the heterogeneous network region.Network selection strategy in heterogeneous wireless integration network includes two applications. One is the initial trigger access network selection and the other is the vertical handover network selection. This thesis puts forward a new scheme which is discussed based on these two points respectively. A multi-level decision scheme is designed and the best network is filtered successively. Firstly, the received signal strength of candidate networks is utilized to make the primary decision. Then, the traffic load of the candidate networks is taken into consideration to make the secondary decision. At last, the Analytic Hierarchy Process model is employed in the process of the ultimate decision. Through the calculation of subjective weights of service property parameters and objective weights of network properties adopted by the information entropy theory, comprehensive weight can be obtained to calculate the network utility by integrating the subjective and objective weights. The network which has the maximum network utility value can be judged to be the best target one.If the connected network cannot meet the demand of user terminal, vertical handover process is triggered. With regard to the solution of vertical handover process, the primary decision process is changed on the basis of the new scheme. It adopts the relative receiving signal strength to make the primary decision. Tightly coupled architecture is applied to the heterogeneous wireless integration network. Meanwhile, multiple user terminals are randomly distributed in the coverage area of heterogeneous network. Through the MATLAB simulation, the scheme can effectively enhance the user access probability. The network throughput of the whole system is increased, and the network resource is also made of full use.