The Research Of Random Mobility Model Based-on Delay Tolerant Network

Delay Tolerant Network is a branch of Mobile Adhoc Network, there is no static end to end path between nodes in different DTN subnets, so traditional MANET routing protocols can not be used in DTN networks. Communication between nodes in DTN depends on the encounter opportunities caused by nodes which carry the messages moving among different subnets, for the development and evaluation of DTN network routing protocols, the movement of mobile nodes should be study. A lot of random mobility models to simulate movements of DTN nodes have been discussed, but there has not a stardard to measure the closeness between the scenarios described by random mobility model and the actual DTN.In this paper, we first compared the existing DTN routing protocols and mobility models, then summarized the random mobility model characteristics which have impact in evaluation of routing protocols, on this basis, proposed the duel-dimensional analysis method, which combines the related concepts from complex network theory, from the two dimensions of time and space to analyze the characteristics of mobility model. This analysis method can compare the closeness between the scenarios described by random mobility model and the actual DTN. Through the duel-dimensional method analysis between random waypoint mobility model and the actual DTN, found that the time dimension parameters of random waypoint mobility model is close to actual DTN, but a big gap between spatial dimensions, so the random waypoint mobility model can not accurately describe the kind of DTN which has human society features. Subsequently, this paper implemented community-based mobility model under NS-2 platform, After two-dimensional analysis found this model can be a good approximation of human society and has good scalability and configurability, so, community-based mobility model can be basis in DTN study. The dual-dimensional analytical methods and simulation results in this paper have for a certain reference value in research of DTN routing protocol.