Cross Layer Collaboration Based Vertical Handover At Transport Layer

With the rapid development of mobile communication technology, various kinds of wirelessaccess technologies are created in response to the business demand of mass users. Becauseaccess technologies vary in terms of coverage, transmission capability, bandwidth and mobility,etc., one sole network cannot meet particular demands of all users. Therefore we can concludethat the development trend of new-generation communication network must be the integratednetwork with various access technologies co-existing. In order to provide users withcross-system seamless business in the heterogeneous network, how to realize the continuity ofvertical handover of the conversation among the heterogeneous network becomes one of the keyquestions which need to be solved immediately.Because mSCTP does not entail a specific functional entity in the network and the protocolitself is multi-homing and multi-streaming, SCTP is safer and more stable, flexible andapplicable. The transport layer vertical handover based on the mSCTP is becoming the ideal planto solve the handover problem between different access technologies. But the handover strategyfor mSCTP is still researched theoretically and all aspects are not mature enough. In terms ofroute malfunction administrative mechanism of SCTP, if protocol characters of mSCTP are usedto execute vertical handover solely, there would be too much delay.Aiming at the aforementioned defects, this paper proposes a vertical handover model fortransmission layer, by connecting cross-layer cooperation with two-level forecast. This modelcollects QoS (Quality of Service) parameters of each layer by cross-layer cooperation, and usesfuzzy logic algorithm to get a brand new parameter--QoN (QoN represents the quality ofnetwork). Regard QoN as the decisive index during two-level forecast and finish handoverlaunch and decisive preparation before the network quality worsens seriously. When the qualityvalue of the network declines to the set standard, handover is immediately executed. By sendingspecific data block timely in the handover execution stage, it can improve the problems whichare caused by the deficiencies on the mSCTP protocol itself, such as too long handover delay andretransmission of the unnecessary data in the handover execution stage. In the end, throughtheoretical analysis and NS simulation, the paper indicates that the strategy proposed by ourpaper has obviously improved the indexes of handover delay and throughput capacity, etc.compared with current research strategies, which proves the rationality and efficiency of the improved plan.