Abstract

In Disruption-Tolerant Networks, routing is one of the most challenging and open problem, because the wireless links are short-lived. The connection between the nodes in the network changes over time and the nodes do not move completely at random. Instead they move around a set of well-visited locations. The routing is done based on the prediction of future contacts by using the node’s mobility history. The node’s mobility is estimated based on the history of observations. The existing DTN routing methods predict whether two nodes would encounter each other, without considering when the contact occurs. In the proposed Predict and Relay method, the routing is done based on the prediction of contact times, which focus on the time-based mobility prediction. The Time-Homogeneous Semi-Markov model is used to predict the node’s future contacts and the time of contact. After predicting the mobility, the relay node is selected that has the highest probability of delivery to the destination. Packets are forwarded hop-by-hop in the succession of contacts. The simulation result shows that this approach improves the delivery ratio and also reduces the energy required to predict the node’s mobility and the delivery latency.