Wireless Powered Communications: A New Communication Paradigm

Dr. Ioannis Krikidis, krikidis@ucy.ac.cy
University of Cyprus, Greece

Dr. Ioannis Krikidis (Fellow, IEEE) received the Diploma degree in computer engineering from the Computer Engineering and Informatics Department (CEID), University of Patras, Greece, in 2000, and the M.Sc. and Ph.D. degrees from the École Nationale Supérieure des Télécommunications (ENST), Paris, France, in 2001 and 2005, respectively, all in electrical engineering. From 2006 to 2007, he has worked as a Post-Doctoral Researcher with ENST, Paris. From 2007 to 2010, he was a Research Fellow with the School of Engineering and Electronics, University of Edinburgh, Edinburgh, U.K. He is currently an Associate Professor with the Department of Electrical and Computer Engineering, University of Cyprus, Nicosia, Cyprus. His current research interests include wireless communications, cooperative networks, 5G communication systems, wireless powered communications, and secrecy communications. He was a recipient of the Young Researcher Award from the Research Promotion Foundation, Cyprus, in 2013, and a recipient of the IEEE ComSoc Best Young Professional Award in Academia, in 2016, and the IEEE Signal Processing Letters Best Paper Award in 2019. He has received the prestigious ERC Consolidator Grant. He serves as an Associate Editor for the IEEE Transactions on Wireless Communications, IEEE Transactions on Green Communications and Networking, and IEEE Wireless Communications Letters. He is also the Founding Specialty Chief Editor of communication theory in Frontiers Communications and Networks. He has been recognized by the Web of Science as a Highly Cited Researcher for 2017-2020.

Dr. Constantinos Psomas, psomas@ucy.ac.cy
University of Cyprus, Greece

Dr Constantinos Psomas (Senior Member, IEEE) received the B.Sc. degree in computer science and mathematics from the Royal Holloway, University of London, in 2007, the M.Sc. degree in applicable mathematics from the London School of Economics in 2008, and the Ph.D. degree in mathematics from The Open University, U.K., in 2011. From 2011 to 2014, he was as a Post-Doctoral Research Fellow with the Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology. He is currently a Research Fellow with the Department of Electrical and Computer Engineering, University of Cyprus. His current research interests include wireless powered communications, cooperative networks, and full-duplex communications. He received the Exemplary Reviewer Certificate from the IEEE Transactions on Communications for 2020 and the IEEE Wireless Communications Letters for 2015 and 2018. He serves as an Associate Editor for the IEEE Wireless Communications and the Frontiers in Communications and Networks.

Motivation

Conventional energy-constrained wireless systems such as sensor networks are powered by batteries and have limited lifetime. Wireless power transfer (WPT) is a promising technology for energy sustainable networks, where terminals can harvest energy from dedicated electromagnetic radiation through appropriate electronic circuits. The integration of WPT technology into communication networks introduces a fundamental co-existence of information and energy flows; radio-frequency signals are used in order to convey information and/or energy. The efficient management of these two flows through sophisticated networking protocols, signal processing/communication techniques and network architectures, gives rise to a new communication paradigm called wireless powered communications (WPC).

The roll-out of the IoT will lead to the massive deployment of sensor nodes and a vast amount of information exchange, making it impractical, even impossible, to individually recharge/control these devices on a regular basis. Powering sensors/devices by continuous and controlled WPT will avoid the inconvenience of replacing batteries or recharging by using cables. Moreover, WPT/WPC will prevent the interruption of critical mobile services, such as health care, finance and public safety, due to exhausted batteries. With sensors and wireless transceivers getting ever smaller and more energy-efficient, we do not only envision that radio waves will become a major source of energy for operating these devices, but also that their information and energy transmission aspects will be unified.

Structure and content

In this tutorial, we discuss the principles of WPC and we highlight itsmain network architectures as well as the fundamental trade-offbetween information and energy transfer. Several examples, whichdeal with the integration of WPC in modern communication systems,are presented. Specifically, we study some fundamental networkstructures such as the MIMO broadcast channel, the interferencechannel, the relay channel, the multiple-access channel, and ad-hocnetworks. The integration of WPC in 5Gand beyond is analyzed anddiscussed through the use of tools from stochastic geometry. Futureresearch directions and challenges are also pointed out.

• Part I (Introduction to WPC): In this part, we introduce theWPT/WPC technology and present its main networkarchitectures. Feasibility issues, potential applications andbasic energy harvesting models are presented. Thefundamental trade-off between information and energytransfer is also introduced through basic examples.
• Part II (WPC from Information Theory standpoint): In thispart, we study WPC from a fundamental point of view thoughinformation theoretic tools. A WPC system aims to (i) reliablytransmit information with a sufficiently small probability oferror; and (ii) transmit energy at a given rate with a sufficientlysmall probability of energy shortage. The information-energycapacity region is derived for basic network topologies.
• Part III (WPC from a Signal Processing standpoint): In thispart, we deal with practical communication and signalprocessing techniques appropriate for WPC systems. Topicsdiscussed include energy beamforming, receiver architecturesfor WPC, relaying, waveform design and multiple-inputmultiple-output (MIMO) for WPC.
• Part IV (WPC from a systemlevel standpoint): In this part, westudy WPC from a system level point of view by usingstochastic geometry tools. We take into account the spatialrandomness of the terminals and we study the integration ofWPC in cellular networks, bipolar ad-hoc networks, sensornetworks and 5G mmWave.
• Part V (WPC from an experimental standpoint): In this part,we highlight some experimental research activities associatedwith the implementation WPC.