Adaptive Decision Algorithm Of Vertical Handoff In Heterogeneous Wireless Interworked Networks

With the development and widely application of WLAN, 3G and WiMax, it has been an essential trendency that different technology in the wireless network can exist simultaneously, work together and compensate for each other. Vertical handoff is a key technique in the combination of heterogeneous wireless network, which can ensure the users to access to the various wireless network adaptively. The premise of whether can meet users'desirement is to ensure that the network selection of QoS and the decision is in a heterogeneous wireless network vertical handoff way.Consider the application and need of the network comprehensively, the heterogeneous wireless network vertical handoff algorithm was studied deeply in this paper. The algorithm can assure the users in the optimum network and meet their need for QoS. The detailed algorithm is as follows:(1) In this paper, we introduced the actual needs of terminal application and the users'prefernces. Meanwhile, we improved the terminal-centric cost function and proposed QoS-guaranteed cost function based on multi-application, giving the network parameter normalization method and application-based network selection algorithm. Based on the combination of 3G and WLAN, we tested the proposed algorithm. The result showed that compared with the algorithm put forward by Wang et al., this algorithm can quickly give the feedback the requirment of delay and bandwidth from the terminal.(2) In order to improve the effective of handoff and meet the requirement of mobile multimedia and other equipment for the handoff delay, we proposed an adaptive network parameter prediction algorithm through the historical information and the analysis of variation of different network parameter.This algorithm includes the establishment of the network parameter predictive function, initialization, forecast and adjust the four processes. Combined with the network cost funcion to realize the heterogeneous wireless network real-time vertical handoff. We had an experiment on the proposed algorithm and the result showed that this algorithm can reduce the ping-pang effect of switching and find the optimum access network earlier, ensuring the users in the optimum network for a long time.(3) Design and development the integration of heterogeneous wireless network access platform. In this paper, we verify the correctness and efficiency of the proposed algorithm and ensure the users'service quality by the heterogeneous wireless network vertival handoff.The result of this paper can be applied in the next-generation wireless network integration scenario and provide the support for the mobile internet and internet of things.