Reserch And Improvement Of WiFi Quick Switch

Recently,because of low cost,quick speed and stability,WiFi becomes more and more popular.Especially in public place,maybe we can scan several APs in the same place.Thus,techniques about WiFi attract more and more people's eyes.How to reduce the handoff latency is one of the hottest topics.Because if a station can not switch between APs,users may be quite unpleasant.Although 802.11 r protocol has solved the latency of authentication phase perfectly,the latency of scan phase is also an unsolved problem.In this paper,through studying and researching 802.11 protocol deeply,a new algorithm is proposed to reduce the latency of WiFi switch.The algorithm is based on the Neighbor Graphs Algorithm from 802.11 f protocol and it needs two steps to decide the target AP and also use a dynamic scanning method to reduce the latency of scan phase.Because the Neighbor Graphs Algorithm has infomation about MAC address of APs nearby,the Probe Request frame need not be broadcast.So it will reduce the number of Probe Response frames to handle the problem of bandwidth insufficient.The proposed algorithm of this paper can work with the 802.11 r protocol perfectly,so it will not influence the process of authentication phase.Then the proposed algorithm is simulated by OPNET Modeler.The simulation results show the algorithm can not only reduce the latency of scan phase but also increase the success rate of switch.In the end,this paper proposes that the success rate of switch takes an more important role than the latency of scan phase in WiFi switch.