De-COP: A Decentralized Community Convergence Approach for Message Forwarding in Pocket Switched Networks

Pocket Switched Networks (PSNs) are an evolution of mobile ad-hoc and Delay Tolerant Networks in which there is no assumption made about the existence of a complete path between two nodes wishing to communicate, thus making routing even more challenging. Various routing algorithms have been proposed over the years like Epidemic, Spray and Wait, ProPHET, etc. There is a separate class of routing algorithms that exploit social structuralism to selectively forward messages to the best candidates. One such algorithm is BUBBLE Rap, which takes into account the notion of popularity and communities to make forwarding decisions. However, popularity as a sole deal-breaker is a rigid policy. We propose a decentralized community convergence-based message forwarding approach viz., De-COP that makes use of the familiarity metric which is dictated by the characteristic of a community to make message forwarding decisions. When familiarity is used for forwarding messages in converged communities, the messages are delivered with low latency and high probability. A community is defined as converged when the change in its membership is gradual. The forwarding node also takes into account the butter availability at the target node to reduce delay and message loss probability. The results were obtained using ONE simulator on two popular datasets, i.e., Infocomm06 and Cambridge to demonstrate the efficacy of the proposed De-COP approach in terms of improved delivery probability and message overhead ratio compared to ProPHET and BUBBLE Rap.