Delay-constrained efficient broadcasting in duty-unaware asynchronous wireless sensor networks

In wireless sensor networks (WSNs), the broadcasting is used for remote network configuration, information dissemination, route discovery and so on by propagating messages across the whole network. To reduce the energy consumption of the asynchronous WSNs, sensor nodes usually adopt independent wake/sleep scheduling. However, this may induce unpredictable waiting delay. In some real-time applications, the broadcasting should be accomplished within a limited time. In this paper, we propose a broadcasting protocol to save energy under a constrained end-to-end (E2E) delay. We estimate the average one-hop delay and use an adjusting factor to balance the remaining delay of continuous hops. Then, we set up a sender candidate node set for each node according to its waiting delay constraint, and choose the least-cost energy node to forward the packet under the constrained waiting delay to save energy. The simulation results show that our broadcasting protocol is more energy efficient than conventional protocols under E2E delay constraint.