Incentive-rewarding mechanisms to stimulate participation in heterogeneous DTNs

Abstract: Delay Tolerant Networks (DTNs) rely on the cooperation of nodes in a network to forward a message from its source to its destination. Most of previous studies on DTNs have focused on the design of routing schemes under the hypothesis that each relay node is willing to participate in the forwarding process. However, the delivery of a message incurs energy and memory costs. In this paper we handle the problem of how to incentivize mobile nodes to participate in relaying messages using a reward mechanism. We consider heterogeneous relay nodes where the cost for taking part in the forwarding process varies as a function of the mobility patterns of the relays. We show that under fairly weak assumptions on the mobility pattern, the expected reward the source pays remains the same irrespective of the information it conveys to the relays, provided that the type of information does not vary dynamically over time. We also characterize the effect of time to live (TTL) counters on the delivery probability and memory usage. Using simulations based on a synthetic mobility model and real mobility traces, we perform a few tests that show a good accordance among theoretical and simulation results.