The Research Of Fast Handoff Technology Of MIPv6Based On IEEE802.11

Mobile IPv6technology has attracted the enthusiastic attention of the majority ofscholars. The switching technology of mobile node in the mobile process is one of the keytechnology and the hot spot in mobile IPv6research. With the maturity of IEEE802.11wireless LAN technology, fast-moving roaming of wireless access point (AP) may begradually realized. This paper conducts a study on how to reduce the delay of Mobile IPv6and to realize the Mobile IPv6seamless handoff based on IEEE802.11wireless LAN.Firstly, the paper elaborates the development background of Mobile IP, the structure ofIEEE802.11wireless LAN and etc, and then introduces the relevant concept of MIPv6, basicprinciple and performance of MIPv6handoff, and summarizes the overall handoff delayeffects of Network layer and Link layer in the process of Mobile IPv6handoff. Secondly,Mobile IPv6enhancement protocol of reducing Network layer handoff delay are studied, andthe selection algorithm of MAP for Hierarchical MIPv6and Fast Hierarchical MIPv6isimproved; Finally, the handoff process of MAC layer and several common scanningalgorithm are analyzed, the Selective Neighbor Caching (SNC) scanning algorithm isimproved, and then its performance are simulated and analyzed.The improved self-adaptive MAP selection plan installs the GPS equipment in thenetwork design for each node to gain to the node information effectively. The time that MNstays in the domain of MAP and the distance vector of MAP in the network are decisivefactors of MAP selection in the improved algorithm. Analysis research shows thatself-adaptive MAP selection algorithm can effectively reduce the communication load, andimprove the performance of Hierarchical MIPv6and Fast Hierarchical MIPv6.The improved SNC scanning algorithm, firstly, extends the structure of neighbor APinformation table, and then re-defines the decision-making scheme of SNC scanningalgorithm taking RSSI as main impact factors and QoS service level, location of AP andmoving direction of MN as secondary impact factors. In the measurement of RSSI, thealgorithm makes Gaussian fitting of its own data to reduce the error generated from themeasurement to improve the stability. In the improved SNC scanning algorithm, the numberof the candidate AP is reduced to one, therefore the communication load is effectivelylowered down and problem of missed candidate AP is settled. Using OPNET Modeler tosimulate the performance of the improved SNC scanning algorithm, results show that thehandoff delay of the improved algorithm is reduced to about7ms and the data packet loss rateis reduced to a very low, which means the improved scanning algorithm can effectivelyimprove the performance of handoff. Applying the improved SNC scanning algorithm toMIPv6, Fast MIPv6, Hierarchical MIPv6and Fast Hierarchical MIPv6to analyze and compare each performance. Analyzing results indicates that application of the improved SNCscanning algorithm is able to reduce handoff delay and data packet loss rate and to guaranteethe service quality of communication.