Article Leveraging Energy Harvesting and Wake-Up Receivers for Long-Term Wireless Sensor Networks Fayçal Ait Aoudia 1, Matthieu Gautier 1,*, Michele Magno 2, Olivier Berder 1 ID and Luca Benini 2 1 University of Rennes, CNRS, IRISA, 6 rue Kerampont, F-22305 Lannion CEDEX, France;
[email protected] (F.A.A.);
[email protected] (O.B.) 2 ETH Zurich, Integrated Systems Laboratory, Gloriastrasse 35, 8092 Zurich, Switzerland;
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[email protected] (L.B.) * Correspondence:
[email protected] Received: 11 April 2018; Accepted: 10 May 2018; Published: 15 May 2018 Abstract: Wireless sensor nodes are traditionally powered by individual batteries, and a significant effort has been devoted to maximizing the lifetime of these devices. However, as the batteries can only store a finite amount of energy, the network is still doomed to die, and changing the batteries is not always possible. A promising solution is to enable each node to harvest energy directly in its environment, using individual energy harvesters. Moreover, novel ultra-low power wake-up receivers, which allow continuous listening of the channel with negligible power consumption, are emerging. These devices enable asynchronous communication, further reducing the power consumption related to communication, which is typically one the most energy-consuming tasks in wireless sensor networks. Energy harvesting and wake-up receivers can be combined to significantly increase the energy efficiency of sensor networks. In this paper, we propose an energy manager for energy harvesting wireless sensor nodes and an asynchronous medium access control protocol, which exploits ultra-low power wake-up receivers.