Sleep scheduling for critical nodes in group-based industrial wireless sensor networks

In large-scale industrial wireless sensor networks (IWSNs), some nodes are likely to be critical to maintain group-connectivity. Prior studies on topology control with critical nodes (CNs) mainly focus on network connectivity inside a group. It is non-trivial to maintain group-connectivity without considering any CNs in group-based IWSNs. Sleep scheduling is one of the approaches to save residual energy of wireless nodes in energy-constraint IWSNs while satisfying network connectivity and reliability. This article focuses on prioritize these CNs to sleep more than other nodes in order to save their energy resulting prolong global connectivity in group-based IWSNs. The proposed sleep scheduling scheme significantly outperforms the state-of-the-art sleep scheduling in terms of number of critical nodes below critical energy, group-connectivity, and ratio of always-awake critical nodes in the group-based IWSNs.