Energy Harvesting Communications

1Introduction

1.1 Background

Energy harvesting wireless communication is one of the most recent advances in communications techniques. It refers to any communications systems that use devices powered by energy from either the ambient environment or a dedicated power transmitter in a cable‐less or battery‐free way. This new method of communications has two main benefits. First, conventional communications devices rely either on batteries or fixed mains connections for energy supply. However, all batteries have a limited lifetime, while mains connections are not flexible. Energy harvesting provides a promising solution to perpetual and flexible operations of communications devices. Specifically, wireless communication replaces the data cable with wireless interconnection, while energy harvesting aims to replace the power cable with harvested energy, the very last cable in wireless communications. Together, energy harvesting wireless communication provides unprecedented convenience for our daily life. Secondly, energy efficiency is a key issue in wireless communications systems. This is particularly important for conventional wireless devices that rely on batteries, such as sensor nodes or mobile phones. Due to this importance, many studies have been conducted to improve the energy efficiency of wireless communications, including green communications. In fact, most studies on modern communications systems are about their energy efficiency or spectral efficiency. For energy harvesting ...