Research On Access Selection Machanism In Heterogeneous Wireless Network

In future,mobile communication networks will form a kind of heterogeneous wireless network environment,where a variety of access technologies coexist and are mutually integrated.User can connect to heterogeneous networks conveniently,rapidly and seamlessly by using Multi-mode terminals with multiple wireless interfaces,thereby obtaining diversified and personalized high quality services.When there are several different types of business which need to access network simultaneously,how to distribute these sessions among the available networks draws more and more attentions.In this paper,we study the access selection mechanism in the heterogeneous network environment based on the features of different business flows and link conditions of the candidate network.We propose new access selection mechanisms,which can make full use of network resources and enhance the users' experience on the basis of meeting QoS(Quality of Service)requirements of various sessions.Firstly,in the heterogeneous network environment,to solve the problem that a single user terminal needs to run several kinds of sessions simultaneously,this paper design an access selection mechanism for a single user that each of the business flows can access to the most appropriate network based on the stream switching mechanism.The access selection algorithm is the key part of the mechanism.This paper uses modified fuzzy TOPSIS(Technique for Order Preference by Similarity to Ideal Solution)to solve the disorder or other problems in traditional TOPSIS,moreover it can adapt to the dynamic changes of the network environment.Secondly,in multi-user scenarios,multiple terminals running multiple sessions need to access the network,increasing the network load,so that it is difficult for each flow to access to the most satisfactory network,and even worse some of them cannot connect to network.In order to solve the problem,this paper introduces the concept of satisfaction.The mechanism uses a new access selection algorithm which is based on the access selection mechanism for a single user.We also design an access control algorithm,which makes the service with higher degree of satisfaction preferential access network.The simulation results show that the access selection mechanism for single user can achieve a reasonable allocation of traffic flows in heterogeneous network environment.The overall average satisfaction of the terminal services is higher than that of all the traffic flows accessing one network.The amount of the terminal handover using this mechanism is lower than that using the traditional TOPSIS algorithm.When the network resources are limited,this paper proposes an access selection mechanism for multi users,which is superior to the priority based session flow assignment strategy in reducing the gap of service completion and improving the overall average service satisfaction,and it optimizes the allocation of network resources.