Dr. Ioannis Krikidis
University of Cyprus, Greece
Dr. Constantinos Psomas
University of Cyprus, Greece
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.
- Lead Guest Editor for IEEE Journal of Selected Topics in Signal Processing-Special Issue on Exploiting interference towards energy efficient and secure wireless communications, December 2016.
- Organizer of Workshopon Wireless Energy Harvesting Communication Networks, IEEE Global Communications Conference (GLOBECOM), 2016, 2017, 2018.
- Organizer of Workshop on Emerging Energy Harvesting Solutions for 5GNetworks, IEEE International Conference on Communications(ICC),2017.
- Organizer of WorkshoponGreenand Sustainable 5G WirelessNetworks (GRASNET), IEEE Wireless Communications andNetworking Conference (WCNC), 2016,2017.
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.