The Research On Cooperation Mechanism In Opportunistic Network Based On Reciprocity

Since the opportunistic network needs the encounter chance brought by nodes mobility to communicate, the cooperation forwarding in the intermediate nodes is necessary in order to send the message to the destination node successfully. Thus, the degree of cooperation among nodes has a significant impact on the performance of opportunistic networks. Theoretically, all nodes in the network are collaborative nodes and can transfer the message to others voluntarily and unconditionally.However, due to the limitation of node’s cache, electricity and other resources, and preference in reality scenario, parts of the network nodes will show some selfishness and refuse to forward the message, which will degrade the success rate of transmission and increase the transmission delay, reducing the network performance greatly. So, how to promote the nodes to work together in the network is an urgent problem to be solved in the opportunistic network.At first, this paper will introduce the basic principles of opportunistic networks briefly, as well as the current research progress and challenges, analyzing the advantages and disadvantages of existed cooperation strategy in stimulating selfish nodes in detail. Then for social attributes that nodes showed in real scenarios in the opportunistic network, we will research the behavioral features of nodes, analyzing the reason that nodes do not cooperate, proposing a opportunistic network cooperation mechanism based on altruistic punishment with the combination of relevant content in behavioral economic research(referred to AP mechanism). By punishing the selfish nodes for its uncooperative behaviors through altruistic punishment node in AP mechanism, node’s selfish behavior can effectively restrained, node’s cooperative probability can improved, keeping the degree of whole network cooperation in a higher level. This paper carried out an simulation experiment through ONE platform in order to verify the effectiveness of AP mechanism. The experimental result indicates that the successful delivery rate of message can effectively improved under the modes of single-copy route and multiple-copy route. Especially nuder the mode of single-copy route, message delivery rate improves more obviously, and the network reach a level that all nodes are cooperate. AP mechanism can also reduce node’s energy loss in some degree. Comparing with the mechanism that all nodes are cooperation nodes, the average relative surplus energy in AP mechanism is apparently higher than that in the mechanism.Finally, from the perspective of encouraging nodes to actively cooperate in the network, this paper proposes a opportunistic network cooperation mechanism based on altruistic reward(referred to AR mechanism). By giving a certain amount of reward points to nodes that actively participate in network service through AR mechanism,nodes’ priority ranking can be improved, and then message’s priority level to be forwarded that nodes carried can be improved. In order to verify the effectiveness of AR mechanism,this paper carried out an simulation experiment and compared it with Direct Delivery, PROPHET and TFT these three classical solutions in network performance. The result shows that on the premise that message delivery rate remains high, AR mechanism can decrease node’s energy loss effectively and reduce network overhead.