Exploiting small world properties for message forwarding in delay tolerant networks

In Delay Tolerant Networks (DTNs), the connections between mobile nodes are always disrupted and constant end-to-end paths rarely exist. In order to cope with these communication challenges, most existing DTN routing algorithms favour the "multi-hop forwarding" fashion where a message can be forwarded by multiple relay nodes in the hope that one of the employed relay nodes can deliver the message to the destination node. Since aggressively employing relay nodes may incur the intolerable delivery cost in DTNs, it is meaningful to design a cost-efficient routing algorithm that can achieve a high delivery performance. In this paper, we first design a novel delivery metric to measure the forwarding capability of nodes. Then, we utilize small-world properties to design the principles of relay node selection, e.g., limiting the number of relays and finding the appropriate relay nodes, and further develop a cost-efficient social-aware forwarding algorithm called TBSF. Extensive simulations on real mobility traces are conducted to evaluate the performance of TBSF, and the results demonstrate its efficiency and usefulness.