Optimal Forwarding in Opportunistic Delay Tolerant Networks with Meeting Rate Estimations

TL;DR

This paper introduces optimal forwarding algorithms for opportunistic Delay Tolerant Networks that adapt to meeting rate estimations, aiming to maximize delivery success while minimizing latency and resource usage.

Contribution

It presents both centralized and decentralized algorithms that are proven optimal under certain assumptions, with a novel recursive likelihood-based meeting rate estimation method.

Findings

Algorithms significantly improve delivery latency and success rates.

Decentralized estimation effectively adapts to network dynamics.

Numerical simulations confirm performance gains on real-world datasets.

Abstract

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 a-priori 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 behaviour, 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.