In this work, we investigate the use of epidemic routing in energy constrained Delay Tolerant Networks (DTNs). In DTNs, connected paths between source and destination rarely materialize due to the mobility and sparse density of nodes. Epidemic routing is well-suited for these environments due to its simplicity and fully distributed implementation. In epidemic routing, messages are relayed by intermediate nodes at contact opportunities, i.e., when pairs of nodes come within transmission range. Each node needs to decide whether to forward its message upon contact with a new node based on its residual energy level and the age of that message. We mathematically characterize the fundamental tradeoff between energy conservation and forwarding efficacy as a heterogeneous dynamic energy-dependent optimal control problem. We prove, somewhat surprisingly given the complex nature of the problem, that in the mean field regime, the optimal dynamic forwarding decisions follow simple thresholdbased structures in which the forwarding threshold for each node depends on its current remaining energy. We analytically establish this result under generalized classes of utility functions for DTNs. We then characterize the dependence of these thresholds on current energy reserves in each node.
In REF Khouzani and Eshghi have examined the purpose of epidemic routing in energy constrained DTN.
Optimal energy-aware epidemic routing in DTNs
MobiHoc '12
Computer Science