Research On Key Technologies Of Ferry Nodes In Opportunistic Networks Based On Node Clustering

Opportunistic network is a mobile ad hoc network that completes message forwarding in the way of "store-carry-forward" without network infrastructure,relying on encounter opportunities brought by node movement.In an opportunistic network composed of node clusters,sometimes there is no link required for message forwarding between clusters,and each node cluster is in a state of communication isolation.It is of great significance to deploy Ferry nodes between node clusters to and from regions to achieve overall network connectivity.Identifying and deploying Ferry nodes in an opportunistic network,and reasonably scheduling and managing Ferry nodes can prolong network life and improve network performance.There are few related researches on the identification of Ferry nodes in opportunistic networks,and the existing work has the problem of low identification accuracy.At the same time,since the Ferry node undertakes the work of message forwarding between node clusters in the network,it usually has the characteristics of handling a large number of messages,consuming large amount of energy,and forwarding with long period compared with ordinary nodes.Therefore,it is necessary to design an opportunistic network routing algorithm according to the characteristics of Ferry nodes,so as to efficiently utilize the limited resources of Ferry nodes.However,none of the existing Ferry node routing algorithms involve the integration of Ferry node motion path planning and Ferry node cooperative work,resulting in difficulty in Ferry node path planning and low efficiency of cooperative work.In response to the above problems,the main contributions of this research are as follows:1)A Ferry node cluster identification model based on structural holes and K cores is proposed.In this thesis,a Ferry node cluster identification model based on the Ferry?Importance?Rank(FIR)index is constructed.On the basis of the importance of structural holes and the importance of K kernels,an FIR index for evaluating the overall contribution of nodes to the opportunistic network is proposed.The indicator designs a Ferry node cluster identification model.Compared with the Ferry node recognition algorithm based on betweenness centrality,the recognition accuracy of this model reaches 100%.2)A Ferry node cluster cooperative work routing strategy(ORABAC)based on active planning path is proposed.This strategy realizes the cooperative work of multiple Ferry nodes under the condition of actively planning the movement path of Ferry nodes,reduces the access of Ferry nodes to invalid areas,decreases the number of repeated visits of different Ferry nodes to the same area,and decreases the delay of message forwarding,which improves the node resource utilization.Compared with the method based on fixed path and the method based on Ferry node layering,this strategy has higher message delivery rate and lower message forwarding delay,and the survival time of Ferry node is also longer.