| Delay Tolerant Network(DTN) is a class of network architecture that experience long transmission delay and intermittent connection. Stable end-to-end paths between nodes may not exist in DTN, but it is similar to some network architecture in real world, so DTN has raised extensive attention. Compared with wired communication networks and wireless mobile ad hoc network, the research of DTN multicasting is more challanging because of the long transmission delay, intermittent connection and node mobility. In this thesis, a new DTN multicast algorithm is proposed, and also we discuss the application of the new algorithm to disseminate information.Based on analysing the architecture and routing protocol of DTN, we firstly propose a new multicast routing algorithm for DTN named Multiple Node Patterns Based Multicasting (MNPM), two node patterns exist in MNPM, which are static node and mobile node, static nodes only select next-hop according to local topology information when they forwarding messages, and messages are forwarded to the selected static nodes by mobile nodes; secondly we analysed the transmisson delay between neighboring static nodes in theory; then MNPM is used to disseminating traffic information in vehicle navigation, weight of road can be caculated based location information and transmission delay, we also propose a specific forward strategy between static nodes and a new method of estimating travel time, vehicles can get real time information from the node to pland a reasonable path based on the navigation metric of shortest travel time.Finally, based on the imported map data, MNPM and vehicle navigation are simulated in ONE(Opportunistic Network Environment). The simulation results not only show the advantage of MNPM in transmission delay and packet delivery ratio, but also show that applying MNPM to disseminate traffic information in vehicle navigation can reduce the travel time of vehicles and alleviate the traffic congestion effectively. |
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