Content-Based Wake-Up for Top-k Query in Wireless Sensor Networks

This article proposes content-based wake-up control for top-k query in wireless sensor networks, where the sink attempts to collect information on top-k nodes or top-k values from sensor nodes employing wake-up receivers. The wake-up procedure is designed with a goal of waking up only the subset of nodes which have the relevant data observations to construct the desired top-k set. This prevents the sensors with less relevant data from waking up and wasting energy. Assuming p-persistent carrier sense multiple access (CSMA) as the medium access protocol, the proposed scheme is analyzed theoretically in terms of data collection delay and total energy consumption. The performance of the proposed wake-up control is examined over a wide variety of parameters with practical considerations and compared to the conventional identity (ID)-based wake-up (IDWu) such as unicast wake-up (UCWu) and broadcast wake-up (BCWu). The obtained numerical results show that the proposed CDCoWu outperforms IDWu in terms of data collection delay and energy consumption for the maximum ratio of top-data to number of sensor nodes ranging from 0.1 to 0.5 when the number of sensor nodes is equal to or more than 20.