Cost Competitive Approaches For Powering LP-WAN IoT Nodes With Harvested Energy (Energy Harvesting Europe 2017)

LP-WAN nodes and WPAN nodes are important elements in IoT networks.

LP-WAN technologies allow small amount of data to be efficiently transferred over long distances. WPAN systems are mainly used for short range communication. Although both systems are often qualified as low power, there are nonetheless considerable differences between them as far as power requirements per frame are concerned. Long range is often achieved at the cost of the data rate, leading to more energy, since data transmission or reception require more time. This increase in energy also affects the ability of using cost-competitive energy harvesting techniques for LP-WAN systems. Today, most examples involving LP-WAN are based on the use of batteries or mains. In this presentation, we discuss our recent activities targeting the use of energy harvesting for LP-WAN. Using measurements that we carried out, we first show the differences in energy requirements between WPAN nodes and LP-WAN nodes, in order to highlight the associated challenges. We then proceed to present a design that uses energy harvested from a small (thus low- cost) solar panel to power a sensor node and enable long range communication with LoRa. The design is also fitted with technology that enables the system to store energy for work when there is not enough light. Variations of the design are discussed, to show how it can be adapted to different load requirements. We then explain how the design and results conforms to the requirement of the LoRaWAN network that is now being deployed in Switzerland. We present results of the on-going tests that show that hundreds of messages can be generated by the LP-WAN node we designed, greatly exceeding the maximal daily limit of our LoRaWAN network operator.

Prof. Marcel Meli is lecturer and Head of the Wireless System Group at the Institute of Embedded Systems, ZHAW, Winterthur, Switzerland. After studies in electrical engineering, he worked on the development of embedded systems and in the semiconductor industry. He has been involved in teaching and research for more than 15 years. His research interests are in low power wireless embedded systems, including microprocessors, wireless communications and energy harvesting. He a frequent speaker at events related to low power embedded systems and the author or co-author of several patents. He holds a PhD degree from the University of Wales, Great Britain.

The ZHAW Zurich University of Applied Sciences is one of the leading universities of applied sciences in Switzerland. Teaching, research, continuing education and other services are both scientifically-based and practice-oriented.

As one of the leading Engineering Faculties in Switzerland, the ZHAW School of Engineering emphasises topics which will be relevant in the future. Distributed systems embedded in processes, also called Cyber-Physical-Systems (CPS), as well as industrial communications solutions, form the core competencies of the Institute of Embedded Systems (InES). Thanks to their networking between themselves and the Internet, these systems make up the Internet of Things, which is increasingly pervading all spheres of life. Our mission is developing products, implementing projects, transferring innovative solutions into practice and research.