A Community-Based Opportunistic Routing Protocol in Delay Tolerant Networks

In Delay Tolerant Networks (DTN), the nodes are sparse and intermittently connected, the end-to-end connectivity between nodes is rare. To overcome the intermittent connectivity, DTN routing protocols employ the “store-carry-forward” strategy to transmit messages. A message is delivered to a destination node from a source node via opportunistic contacts between intermediate nodes. In addition, nodes in DTN have a feature of community. In a community, network node meet each other regularly, while between communities there are only few encounter opportunities. In this paper, we propose a community-based opportunistic routing protocol which works in two modes, the Intra-community mode and the inter-community mode. In Intra-community message transmission, we adopt reasonable forwarding conditions and E-PRoPHET algorithm to design the transmission mechanism. In inter-community message transmission, we use the communication probability and the remaining energy to select the most suitable forwarding node. All of these are designed to limit the number of copies of messages, so as to ensure the performance of the algorithm. We extensively simulated our proposal and have shown that our proposed protocol can raise the delivery ratio, reduce the delivery delay and improve the efficiency of forwarding messages.