Research On Mobile Model And Routing Algorithm For DTN Network In Emergency

With the rapid development and popularization of mobile electronic devices like Bluetooth and Wi-Fi etc, mobile users can contact with each other during they are moving, which makes it probable for network contact in the absence of communications systems. There has been many new types of mobile networks, such as mobile ad hoc networks, delay tolerant network (DTN), etc. Therefore, the characters of these new networks are being widely used in terrestrial mobile network, wildlife tracking network, wireless military battlefield network, hand-held device network, disaster rescue, inter-planetary network, and vehicular ad hoc networks.Communication between nodes is created during they are moving in DTN. However, the mobility of node is uncertain, and the energy, capacity, communication number and processing capacity of mobile devices equipped by mobile nodes are limited, all these make it difficult to maintain a fixed end-to-end communication path between the source node and the destination node. What’s more, the network topology changes constantly, resulting that all existing network models based on the TCP/IP protocol are not fit for these challenging the limited networks. In order to solve the problems about how to create the movement model of node and select the next relay node in case of emergency, this paper proposes a new movement model and a efficient routing algorithm based on the characteristics of movement patterns and messages transmission mechanism under emergency situations in DTN.In this paper, by the analysis of the mobility patterns of mobile users in real life, as well as the research results of some typical movement model of DTN network in recent years, we summarize the design principles of constructing movement model and its components, classify and introduce the movement models in detail. Then we design the earthquake rescue movement model based on DTN for disaster situations by analyzing the movement features of disaster victims and rescue team. Accordingly, through analyze limited cache of the user carrying the equipment, a route cache management strategy is presented for the earthquake rescue. Through the OpenJUMP modeling of a part of Ya’an earthquake, using opportunistic network environment simulator(ONE) to evaluate the performance of this routing algorithm and movement model compared with some classical routing algorithms and movement models in DTN, the experiment proof that the different movement model of the disaster and rescue team has a large influence on network performance, and the cache management strategy can provide an effective reference for earthquake rescue.Then this paper analyze the emergency environment’s communication system, and the trust probabilistic routing algorithm based on Markov process suitable for emergency environment is put forward. Our algorithm is built according to the nodes under disaster environment can forward messages to rescuers timely, effectively and correctly modeling, and make encounter probability prediction and evaluate trust degree between nodes. Then a Markov decision process is abstracted from the process how to choose the next relay node. Based on the above proposed movement model and cache management strategy, this paper makes comparable evaluation among the above routing algorithm and some classical routing algorithms in DTN using ONE simulator.