Periodical Top-kRanking Query in Wireless Sensor Networks Exploiting Wake-Up Receivers

Abstract

This paper proposes an energy–efficient wake–up control for periodical top– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> query in wireless sensor networks employing wake–up receivers. The wake–up procedure is designed in such a way that it only activates a subset of nodes that contribute to grasping the information on the top– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> ranking set with high accuracy, which prevents unnecessary wake–up of irrelevant nodes. The proposed scheme exploits the temporal correlation of observed data with a transmission suppression control executed according to the previous top– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> set, which is notified from the sink to wake–up receivers by a designated signaling. Furthermore, the validations on the estimated top– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> set are conducted by exploiting two different types of wake–up control: identity–based wake–up and content–based wake–up. With computer simulations, we show that our proposed scheme can finely control the trade–off between the accuracy on top– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> set and energy efficiency, and it can achieve high energy saving of sensor nodes in comparison to the other wake–up control designed for the top– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> query. We also investigate the practicality of the proposed wake–up control by implementing its operations into a prototype of sensor node with wake–up receiver. Furthermore, we analyze the computational complexity of our proposed wake–up control.