A Constraint-Based Forwarding for Multi-hop Broadcasts in Asynchronous Duty-Cycled WSNs

Broadcasts for duty-cycled wireless sensor networks (WSNs) has been extensively studied recently. However, in this paper, we investigate a constraint-based forwarding for multi-hop broadcasts in asynchronous duty-cycled operations, and propose a novel Delay-Constrained and Energy-Balanced broadcast protocol called DCEB protocol. In DCEB protocol, without any central node, a distributed algorithm for constructing a broadcast backbone is presented, including its energy-balanced maintenance mechanism. Then, the decision conditions for broadcast forwarding time with or without delay constraint are deduced. Different from current studies, DCEB neither assumes time synchronization for sleep scheduling, which requires all neighboring nodes to wake up at the same time, nor assumes duty-cycled awareness, which makes the protocol difficult to use in duty-cycled WSNs. Under different network configurations, we evaluate DCEB protocol with real sensors and confirm that DCEB reduces much more broadcast cost by the decision conditions and provides better broadcast performance than the Unicast Scheme.