Wireless Charging Technologies: Fundamentals, Standards, and Network Applications

Abstract

Abstract-Wireless charging is a technology of transmitting power through an air gap to electrical devices for the purpose of energy replenishment. The recent progress in wireless charging techniques and development of commercial products have provided a promising alternative way to address the energy bottleneck of conventionally portable battery-powered devices. However, the incorporation of wireless charging into the existing wireless communication systems also brings along a series of challenging issues with regard to implementation, scheduling, and power management. In this article, we present a comprehensive overview of wireless charging techniques, the developments in technical standards, and their recent advances in network applications. In particular, with regard to network applications, we review the static charger scheduling strategies, mobile charger dispatch strategies and wireless charger deployment strategies. Additionally, we discuss open issues and challenges in implementing wireless charging technologies. Finally, we envision some practical future network applications of wireless charging.

Wireless Power Transfer Protocols in Sensor Networks: Experiments and Simulations

“…In [3], the reader can find an extensive overview of wireless charging techniques, the developments in technical standards, and their recent advances in network applications. In particular, with regard to network applications, the authors review the static charger scheduling strategies, mobile charger dispatch strategies and wireless charger deployment strategies.…”

“…Wireless Power Transfer technologies can be broadly classified into non-radiative coupling-based charging and radiative radio frequency (RF) based charging [3]. The former consists of three techniques: inductive coupling [4], magnetic resonance coupling [5] and capacitive coupling [6], while the latter can be further sorted into directive RF power beamforming and non-directive RF power transfer [7].…”

The Performance of Wireless Powered MIMO Relaying With Energy Beamforming

“…In the case of energy-constrained single antenna relay (i.e., N R = 1), the closed-form lower-bound outage 6 Note that in contrast to (19), the information outage probability is defined as the probability that the instantaneous mutual information, I = 1 2 log 2 (1 + γ), falls below a target rate of R 0 bits per channel use. Note that the pre-defined SINR threshold may be given as γ T = 2 2R 0 − 1.…”

“…However, in the presence of CCI interference, MRT and MRC are sub-optimal as they treat the interference as additive noise. Meanwhile, as far as a closed-form simple analytically tractable overall SINR expression is concern, a sub-optimal solution for the receive combining weight vector at the destination is found by applying the zero forcing (ZF) precoding scheme, where the interference term P (5) is forced to zero assuming that N D > M , i.e., we add the ZF constraint G † v R = 0 to the optimization problem in (6). To this end, due to the separability of the problem in (6), the optimization problem could be separated into two simpler problems as follows…”

“…However, the naturally harvested energy is random and highly dependent on the weather conditions, thus, impinging on the whole reliability of wireless communications. Recently, wireless power transfer (WPT) is introduced to overcome such problem, where energy is harvested through ambient radio-frequency (RF) signals [1]- [6].…”