Research On Data Routing Algorithms For Opportunistic Social Networks

With the rapid development of wireless communication technology and the widespread popularity of mobile terminal devices(such as smart phones,iPad,etc.),these devices can achieve short-distance wireless communication through Wi-Fi and Bluetooth.Thus,the Opportunistic Social Networks(OSNs),which have immeasurable potential value in the fields of vehicle network,disaster rescuing,remote-area communications,mobile commerce and so on,have formed without relying on the base stations.On the one hand,due to the discontinuity of the network connection and the uncertainty of the network topology,nodes in OSNs use a "storage-carry-forward”mechanism to forward messages,which relies heavily on the cooperation of relay nodes.On the other hand,the subject carrying the mobile terminal device is our human beings,and the sociality and complexity of the human cause the message to perform an extremely high level of uncertainty in the process of transmission.Thus,how to select a suitable relay node does play a significant role in message forwarding.This paper introduces the research background and significance of the opportunistic social network,the present research situation home and abroad,and the opportunistic social network routing algorithm.Based on the analysis of existing algorithms,we find that most of the routings can achieve good performances in specific simulation scenarios,but such results generally assume that network resources(cache,energy,etc.)are sufficient and nodes are willing to forward messages.Moreover,in the actual application scenarios,the nodes infer to mobile terminal devices carried by people,and both specific social relationships among people(friends,families and strangers,etc.)and some properties of themselves(interest,selfishness etc.)play an important role in message forwarding in the network.Therefore,on the basis of fully considering the social and self-attributes of human beings,the main contributions of this paper are as follows:1)We propose a routing algorithm based on interest and trust.In the OSNs,because of the "small society" characteristics of human mobility and the regularity of human mobility,people who meet today may also meet tomorrow.Moreover,in real life,the people who have the familiar interests tend to be together.Considering that,we propose an interest model of nodes,in which each user has its own interest set,and we can calculate the similarity of interest between every pair of nodes.The higher level of the similarity is,the more probabilities that they will encounter are.And the interests of the nodes are dynamic rather than static.As we know,each node in the network prefers to receive the content that it is interested in.Therefore,the interest of the node can be reflected from the message currently received itself.In this paper,we calculate the changes of the nodes' interests through the messages received by the nodes in the last three periods.To ensure the security of message forwarding,we also propose a trust model of the node.We use the number of messages transmitted by the node in one period to evaluate the trust value of the node.For the nodes that do not frequently transmit messages,we use the Ebbinghaus forgetting curve to characterize the change of trust values between nodes.Finally,based on the similarity and trust value of nodes,a routing algorithm is proposed to select the appropriate middle node.The simulation results show that the proposed routing algorithm has higher delivery rate and lower load rate,which also verifies the validity and accuracy of the algorithm.2)Probabilistic routing algorithm based on game theory model.In opportunistic social networks,due to limited resources and poor social relations,many nodes show strong selfishness,which is not conducive to participate in message forwarding.To tackle this issue,we propose a Probabilistic Routing scheme based on Game Theory(PRGT)to stimulate cooperation among selfish nodes.Firstly,we regard every message as a commodity,naturally,each node has some virtual money to buy commodities(messages)to get more profit.Secondly,according to the historical meeting records among nodes,we establish a Markov-based probability prediction model,in which the message carrier selects a node with higher probability of encountering the destination node as the relay node.Then,we explain the reasons for the selfishness by our proposed game theory model,that is,in the process of message forwarding,the relay nodes not only fail to make profits,but also damage its own benefits.In order to solve the selfishness of nodes,we adopt an incentive scheme to encourage nodes to participate in message forwarding.Finally,we propose a probabilistic routing algorithm based on game theory model.The simulation results demonstrate that our proposed routing scheme can effectively improve the delivery rate of messages and reduce network latency.