Research On Vertical Handover Algorithm In Heterogeneous Converged Network

With the rapid development of communication technology and network access technology, various wireless access technologies exist together. Different networks complement and compete with each other, which constitute the heterogeneous wireless converged network. Among them, the most representative member is the mergence of WLAN and 3G network. WLAN has the characteristics of high bandwidth and low coverage, and 3G network has the characteristics of low bandwidth and high coverage. So the mergence of WLAN and 3G network can complement each other and make use of both advantages. How to make the users roam seamlessly in the complexed heterogeneous network environment?This is the key research content of the vertical switching technology of the heterogeneous converged network. Therefore, this paper analyses and researches vertical switching technology of the heterogeneous converged network through 3G and WLAN.First of all, the system structure of heterogeneous converged network, the basic concept of network vertical switching and the current commonly used vertical handoff algorithm is introduced. Synchronously, the typical network vertical switch algorithm is analyzed contrastively and summarized detailedly.Secondly, based on the network converged structure covered by both 3G and WLAN, a kind of joint network switching decision algorithm based on cost function is presented, and a network vertical switching performance evaluation model which is used for objectively evaluating the performance of the algorithm is established. By evaluating the network bandwidth, the average received signal strength, and the satisfaction factor in application, the algorithm designs the cost function with multiple parameters, so as to quantify the performance of network. The fact shows that comparing with the traditional network switching algorithm based on delay margin, the joint network switching algorithm based on cost function can more effectively reduce the ping-pong effect of the network switching and provide users with higher QoS guarantee.Finally, based on the load balancing problem of the converged network, a network vertical switching algorithm based on groups of game theory is presented. a network access selection mechanism to users is introduced, which according to the utility function acquired by the users in the network, the network utility model by non-cooperative game method is established, and the non-cooperative game meets the potential game condition is proved. The simulation results compare the income characteristics of all the groups and the access network in non-cooperative game model on the condition of 3G and WLAN integration, simulates the user network vertical switching process, and obtains the Nash equilibrium, verifying the theoretical analysis results.