The Research On Characteristics Of Wireless Link Intermittent Connection In Opportunistic Networks

Because of nodes movement, running out of energy, human interrupt, natureinterrupt, which lead to the contacts of wireless link between nodes are intermittent inopportunistic network. That leads to the unstable wireless link which exerts animportant influence on optimizing routing protocol, improving buffer management andoptimizing congestion control. Firstly, the paper sums up and concludes about theproject background, research situation of opportunistic network and so on. And on thisbasis we analyze certainty events and uncertainty events which caused intermittentconnection of link in opportunistic networks. Meanwhile we analyze and concludeseveral kinds of routing protocols.Secondly, we obtain the cumulative distribution function of the contact durationtime and the inter-contact time by through numerical analysis and curve fittingconsidering impacts of mobile speed and transmission ranges on the characteristics ofcontact duration time and inter-contact time of the nodes based on the RandomWaypoint Mobility Model (RWP). On the basis of the mobility model, we research oncharacteristics of contact duration time and inter-contact time of the nodes consideringthe node detection mechanism. In order to further analysis and research thecharacteristics of wireless link intermittent connection of opportunistic networks, thispaper analysis probability distribution of contact duration time and inter-contact timeof nodes. The results are compared with the wireless link characteristics based on RWP. Ultimately, the paper comes to conclusion on the characteristics of wireless linkintermittent connection of opportunistic networks.Finally, on the basis of the analysis of the characteristics of wireless linkintermittent connection of opportunistic networks as well as considering characteristicsof Epidemic, PROPHET and BSW, we research an improved routing protocol basedcharacteristics of inter-contact time (ICRP). ICRP not only control messagereplications but also increase delivery ratio and reduce delay and overhead ratiothrough adding the parameter of social performance and inter-contact time of nodes inthe forward process of messages. We chose the ONE as simulation software to analyze.Simulation results show that ICRP increase delivery ratio and reduce AverageEnd-to-End delay and overhead ratio than Epidemic, PROPHET and BSW.