Optimal Forwarding in Opportunistic Delay Tolerant Networks With Meeting Rate Estimations
Shohreh Shaghaghian, Mark Coates · IEEE Transactions on Signal and Information Processing over Networks · 2015
Data transfer in opportunistic delay tolerant networks (DTNs) must rely on unscheduled sporadic meetings between nodes. The main challenge in these networks is to develop a mechanism based on which nodes can learn to make nearly optimal forwarding decision rules despite having no apriori knowledge of the network topology. The forwarding mechanism should ideally result in a high-delivery probability, low-average latency, and efficient usage of the network resources. In this paper, we propose both centralized and decentralized single-copy message forwarding algorithms that, under relatively strong assumptions about the networks behavior, minimize the expected latencies from any node in the network to a particular destination. After proving the optimality of our proposed algorithms, we develop a decentralized algorithm that involves a recursive maximum-likelihood procedure to estimate the meeting rates. We confirm the improvement that our proposed algorithms make in the system performance through numerical simulations on datasets from synthetic and real-world opportunistic networks.