Low-latency TDMA sleep scheduling in wireless sensor networks

Sleep scheduling is a widely used mechanism in WSNs to reduce the energy consumption since it can save the energy wastage caused by idle listening. In traditional TDMA sleep scheduling, sensors are assigned with consecutive time slots to save the energy consumption of state transitions. However, this consecutive time slots allocation scheme will lead to a longer time delay when data is transmitted from a leaf node to a sink node when nodes are organized in a tree model topology. To address this problem, we present a novel contiguous link scheduling called hierarchical link scheduling with proactive time slots acquisition (H-TSAC). Its main novelty is that contiguous time slots can be acquired by each node to transfer object data based on the layer of nodes in the tree model topology, therefore, a new-type node named multi-parent node is designed to proactively control time slots. The simulation studies corroborate the theoretical results, and show the efficiency in using the H-TSAC scheme.