An Adaptive Vertical Handover Algorithm That Orients To Group Users

With the rapid development of communication technology and computer technology,a large number of wireless communication technologies have emerged in communication systems.As a technology that integrates multiple wireless networks,the convergence of heterogeneous networks is an irresistible general trend of the development of modern communication technology.The vertical handover is a key technology to ensure the session continuity of terminal in heterogeneous networks,as a criterion for network selection,the vertical handover decision is extremely important in the entire vertical handover process.The group handover studied in this paper refers to the phenomenon that a large number of users in a heterogeneous network request to access to the same network within a certain period of time.Vertical handover decision algorithms decide the result of network selection according to some verdict information,but most of them only consider the verdict information in the process before handover,then the load of network and network selection results of other users will not include in the decision system.Under such type of decision algorithm,similarly-demanding group users will “selfishly” access to the same network and cause network congestion.In addition,most vertical handover decision algorithms cannot make adaptive processing based on user preference changes and service changes,network decisions are always based on the same criteria and cannot handle fuzzy decision factors,it will lead to a decrease of user experience in heterogeneous networks.To solve the above problems,this paper proposes an adaptive vertical handover algorithm that oriented towards group users.The group users are classified according to the service type,the adaptive algorithm based on fuzzy AHP will be used to adjust the weights of attributes when the user service changes or the terminal power drops to a certain threshold,it enables the vertical handover decision system to make adaptive adjustments based on dynamic demands of users,thereby improving the user experience in heterogeneous networks.The results of handover will be broadcasted after users access to a new network,then the real-time load condition of network will be updated so that other users can incorporate the network load into the judgment system during the network judgment process,which reduces network congestion.Finally,this paper establishes a LTE-WLAN heterogeneous network fusion model based on OPNET simulation software,the algorithm of this paper and the comparison algorithm are simulated and the simulation data is comprehensively analyzed on this platform.The results show that the algorithm proposed in this paper can adjust the attribute weight factors flexibly according to change of user service and power status of terminal,and it propagates the network load conditions successfully,so that other users can incorporate real-time load into the judgment.It shows the proposed algorithm not only improves terminal communication ability and network load situation,but also reduces end-to-end delay and packet loss rate of the network.