Research On Performance Analysis And Optimal Control Of Cooperative Transmission In Opportunistic Networks Based On Selfish Behaviors Of Nodes

With the development of wireless communication technology and popularity of smart devices with short-range communication capabilities,opportunistic network becomes a research hotspot.In opportunistic network,due to the intermittent connection,short duration of the connection and the dynamic change of the network topology,the reliable communication path between the source and destination cannot be available.To overcome the network partitions,opportunistic network introduces the "store-carry-forward" transmission mode and exploit cooperation of nodes to achieve information transmission.Actually,nodes often tend to be selfish and are not willing to transmit the information as the relay nodes,thereby bringing many challenges.Exploiting the latest achievements and theories of the stochastic process and of epidemic model and optimal control,this paper explores the performance analysis and optimal control of cooperative transmission by taking selfish behaviors and probabilistic social relations into consideration.The main contributions of this paper can be summarized as follows:By referring to infectious disease model in complex networks,this paper firstly proposes theoretical model based on the selfish behaviors,such as interest conversion,information discard.Furthermore,another model that is based on the energy-constrained and probabilistic social relations is proposed.Both models can be used to analyze cooperative transmission performance in opportunistic network.Then the accuracy of both models are validated by the Opportunistic Network Environment platform.Further analysis indicates that all the above-mentioned selfish behaviors have a significant impact on the cooperative transmission performance and the degree of impact is related to the probabilistic social relations.Therefore,it is necessary to study the optimal control problems under conditions of limited energy by taking selfish behaviors and probabilistic social relations into consideration.Moreover,this paper describes the problem of optimal control which is based on selfish behaviors and probabilistic social relations by introducing the method of four elements.Then Pontryagin maximum principle is introduced to solve this problem and we find that the optimal forwarding policy conforms to threshold policy.In order to verify the superiority of optimal polices over other polices,we design an optimal static policy.Through comparison,the optimal strategy is superior to optimal static policy.Researches find that the stop time and performance of optimal forwarding policy are closely related to the probabilistic social relations.In summary,this paper carries out some significant researches about performance analysis and optimal control of cooperative transmission in opportunistic network by taking the selfishness of nodes into consideration.Our work has certain academic and practical significance to promote further research of opportunistic network.