Hybrid Community-Based Forwarding: A complete energy efficient algorithm for pocket switched networks

Sensor devices and the emergent networks that they enable are capable of transmitting information between data sources and a permanent data sink. Since these devices have low-power and intermittent connectivity, latency of delivery for certain classes of data may be tolerated in an effort to save energy. Several previously developed algorithms employ models which considers the popularity of individual nodes within communities and forward messages to nodes with higher probability of delivery according to some heuristic. In previous work, we developed Community-Based-Forwarding (CBF) that considers the interactions between communities as a factor in message forwarding. Using this information, CBF is able to exploit intermediate connections between clusters to route messages with more balanced node participation and higher levels of reliability and efficiency. One disadvantage of CBF was an increased delivery latency for some subset of messages that could not be delivered using other algorithms. In this paper, we extend the semantics of CBF with the Hybrid CBF algorithm (HCBF) by optimizing forwarding inside communities by considering the social diversity (measured by Unique Interactions). We find that all performance metrics are improved with this heuristic on a representative set of human mobility traces, but most significantly the message delivery latency is substantially improved over the other algorithms studied.