Research On Intelligent Handover Management Technology In Mobile IPv6Networks

With the rapid expansion of the over IP and the wireless communication technologies,the mobile users have put forward new requests for mobility. The IETF hence has developedseveral approved handover schemes with the mobile IPv6protocol to provide better mobilitysupport. However, there are still some deficiencies, such as high packets loss rate, longhandover latency and serious signaling interactive overhead, resulting in unfriendlyexperience for real-time or throughput-intensive applications. Consequently, furtherimproving the handover performance in the MIPv6networks, as a significant theoretical andpractical issue, has attracted an extensive body of research.Upon the deep analysis of the standard handover process in MIPv6and the improvedschemes, the current challenges and the causes have been addressed. The performancebottlenecks in the handover management mainly focusing on the handover triggering process,the selection of target handover network and the handover operation sequences are proposed.Aiming at solving the stated issues, the corresponding solutions have been developed basedon the existing protocol frameworks. The innovative works are stated as follows.(1) Aiming at optimizing the handover triggering process, an initiative movementprediction assisted adaptive handover trigger scheme has been developed. In terms ofanalyzing the features of the movement behavior for the mobile node, an initiative movementpredictive algorithm is designed to predict the movement trend of the mobile node in the timeperiod between the L2trigger and fully accessing into the new access network, and then, theL2trigger mechanism is adaptively adjusted by analyzing the probability of L2trigger andcomprehensively comparing the system costs caused by both generating or not generating theL2trigger. Some effective measures are also introduced to compensate the degradedperformance caused by the false decision owing to the inevitably introduced errors in theprediction process. Intelligent L2trigger effectively eliminates the overhead and performanceloss caused by the false alarm of L2trigger and the missed detection of L2trigger.(2) Aiming at optimizing the selection of target handover network, an active overloadprevention based adaptive MAP selection scheme has been developed. Each MAPperiodically evaluates the load, and then dynamically notifies the access routers (AR) withinthe radio coverage area. If the handover is ready to be executed, the serving AR wouldconsider the load balance among the accessible MAPs and perform the active overloadprevention strategy to obtain the MAP candidates. And then, the optimal MAP is adaptively selected by comprehensively considering the system cost and the average handover latencycaused by each MAP candidate. The system cost and the average handover latency areoptimized, the load balancing among the accessible MAPs is actively achieved, and the MAPselection process transparent to the mobile node effectively avoids the energy cost as well.(3) Aiming at optimizing the handover operation sequences, an intelligent fast handoverscheme using the motion pattern detection has been developed. It mainly implements acombined-detection function between the mobile node and the mobility anchor point toanalyze the motion trail and detect the motion pattern of mobile node. In terms of theprediction and the load status of new access router, the serving MAP determines the way themobile node attaching to the new access point to intellectualize the handover process.Especially, a handover optimization is proposed for the ping-pang mode to avoid redundanthandover operations. With limited overhead, the packets loss rate and the handover latencyare effectively improved, and the network performance is enhanced as a whole.(4) Aiming at optimizing the handover operation sequences for the high-speed MIPv6scenarios, a smooth handover scheme has been developed. It uses the multi-homing feature ofmobile stream control transmission protocol (mSCTP) to rapidly switch the primary IPaddress for the mobile node during the handover process. A new entity named LocationManager is introduced to replace the Home Agent and decouple the functions of locationmanagement and packets transmission to speed up the handover process. A buffer-tunnelscheme is also introduced to reduce the packets loss rate, while the storage cost of accessrouter is reduced by adaptive assigning the buffer size, and the issue of out-of-order packetscaused by the buffer scheme is solved by designing the traffic reorder. The packets loss rate iseffectively reduced, and the whole network throughput is enhanced.The proposed schemes are well applicable for some specific scenarios but also havesome defects, and the simple combination for the handover management process in realistichandover applications has the problems of effectiveness and practicability as well. Therefore,the optimized schemes should be adaptively applied for combination in terms of the practicalapplication requests in the handover management process. With the requests of function,performance and actual deployment in the practical handover management cases, the adaptivecombinations are proposed and analyzed to cooperatively realize the adaptivity, accuracy anduniversality for the handover management process to optimize the network performance.