Delay-aware tree construction and scheduling for data aggregation in duty-cycled wireless sensor networks

Data aggregation is one of the most essential operations in wireless sensor networks (WSNs), in which data from all sensor nodes is collected at a sink node. A lot of studies have been conducted to assure collision-free data delivery to the sink node, with the goal of minimizing aggregation delay. The minimum delay data aggregation problem gets more complex when recent WSNs have adopted the duty cycle scheme to conserve energy and to extend the network lifetimes. The reason is that the duty cycle yields a notable increase of communication delay, beside a reduction of energy consumption, due to the periodic sleeping periods of sensor nodes. In this paper, we propose a novel data aggregation scheme that minimizes the data aggregation delay in duty-cycled WSNs. The proposed scheme takes the sleeping delay between sensor nodes into account to construct a connected dominating set (CDS) tree in the first phase. The CDS tree is used as a virtual backbone for efficient data aggregation scheduling in the second phase. The scheduling assigns the fastest available transmission time for every sensor node to deliver all data collision-free to the sink. The simulation results show that our proposed scheme reduces data aggregation delay by up to 72% compared to previous work. Thanks to data aggregation delay reduction, every sensor node has to work shorter and the network lifetime is prolonged.