Research On Routing Algorithm Of Social-based Mobile Opportunistic Network

With the popularization of smart mobile devices,Mobile Opportunistic Network formed by mobile devices with the ability of short distance wireless communication attracts more and more researchers' attentions,such as Vehicle Opportunistic Network,Social Opportunistic Network et al..In recent years,mobile devices normally carried by humans have been getting closer and closer relationships with the carriers.The movement characteristic of nodes reflects humans' social attributes and motion laws to some extent.Compared with the traditional routing algorithm in Mobile Opportunistic Network,the social-based routing algorithm can obtain better performance,which has become a hot research.SimBet and Bubble are two classic social-based routing algorithms in Mobile Opportunistic Network.Under the deep research on SimBet-based routing algorithms and Bubble-based routing algorithms,two improved routing algorithms are proposed in this thesis.1.Aiming at the problem of high message average transmission delay,which is caused by Super Community and Message Retention in Bubble-based routing algorithms,an improved routing algorithm is proposed.Firstly,the proposed routing algorithm makes rules of not default allowing node's Familiar Nodes joininging its Community and limiting combinations of Isolating Familiar Sets or Isolating Communities for Community Detecting.Then,the proposed routing algorithm designs proper calculation mechanism for Centrality by referring to calculation method of Degeree Centrality and by considering different types of social relationships among nodes and the information of Communities that the message passes by.Finally,the simulation results show that the proposed algorithm can achieve higher messge delivery ratio and smaller message average transmission delay under the condition of the tolerant range of network overhead ratio.2.Aiming at the problem of high messge average transmission delay,which is caused by message "Ping-Pong effect" and the phenomenon that the transmission direction of the long distance message slowly converges to the direction to destination node in SimBet-based routing algorithms,an improved routing algorithm is proposed.Firstly,Contact Information List is updated by the means of converting single long contact into equivalent multiple contacts and by taking contact aging into consideration.Secondly,the proposed routing algorithm defines conceptions of Node Similarity State and Node Similarity State Priority according to Similarity not merely to destiantion node but also to source node and to other nodes.Then the proposed routing algorithm formulates utility funciton of nodes based on Centrality and Similarity to evaluate node forwarding ability according to Node Similarity State and Node Similarity State Prioritiy.Finally,the simulation results prove that the proposed algorithm can reduce message average transmission delay and increase message delivery success ratio under the condition of the tolerant range of network overhead ratio.