Cluster-based Wake-up Control for Top-k Query in Wireless Sensor Networks

This paper focuses on top-k query in cluster-based wireless sensor networks (WSNs) employing wake-up receivers, which aims to grasp the information on top-k data efficiently in terms of energy consumed by sensor nodes. As a wake-up control for top-k query, countdown content-based wake-up (CDCoWu) has been proposed. CDCoWU selectively activates sensor nodes storing data belonging to top-k dataset, and its superiority to a conventional identity-based wake-up (IDWu) has been confirmed for a single-hop network accommodating a large number of nodes. In this paper, we extend these wake-up control to a cluster-based WSN, a common network structure of WSN. The cluster-based WSN contains nodes called cluster heads that relay wake-up signals and data for their cluster members. The proposed cluster-based wake-up control conducts activations and data collections of different clusters sequentially while the results of data collections at a cluster are exploited for reducing unnecessary data transmissions at the other clusters. We also introduce a hybrid mechanism of wake-up control, where a wake-up control employed at each cluster is selected between CDCoWu and IDWu according to its number of cluster members. Our simulation results show that the proposed hybrid wake-up control achieves smaller energy consumption and data collection delay than the control solely employing CDCoWu or IDWu.