Wireless Networks With RF Energy Harvesting: A Contemporary Survey

Abstract

Radio frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to power the next generation wireless networks. As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality of service (QoS) requirements. In this paper, we present a comprehensive literature review on the research progresses in wireless networks with RF energy harvesting capability, referred to as RF energy harvesting networks (RF-EHNs). First, we present an overview of the RF-EHNs including system architecture, RF energy harvesting techniques and existing applications. Then, we present the background in circuit design as well as the state-of-the-art circuitry implementations, and review the communication protocols specially designed for RF-EHNs. We also explore various key design issues in the development of RF-EHNs according to the network types, i.e., single-hop networks, multi-antenna networks, relay networks, and cognitive radio networks. Finally, we envision some open research directions.Index Terms-RF energy harvesting, simultaneous wireless information and power transfer (SWIPT), receiver operation policy, beamforming, communication protocols, RF-powered Cognitive radio network.1553-877X (c) 2 transmission. Traditionally, free-space beaming and antennas with large apertures are used to overcome propagation loss for large power transfer. For example, in 1960's, the authors in [15] demonstrate a small helicopter hovering at a height of 50 feet, powered by an RF source with a DC power supply of 270W operating on 2.45GHz on the ground. In [16], the authors demonstrate a space-to-earth power transfer system using gigantic transmit antenna arrays at a satellite and receive antenna arrays at a ground station. For transmit power of 2.7GW, the power transfer efficiency is estimated to be 45% over a transfer distance of 36000km. During the past decade, with the development in RF energy harvesting circuit, low power transfer for powering mobile terminals in wireless communication systems began to attract increasing attention [17], [18]. The authors in [17] propose a network architecture for RF charging stations, overlaying with an uplink cellular network. In [18], a harvest-then-transmit protocol is introduced for power transfer in wireless broadcast system. Moreover, various modern beamforming techniques are employed to improve power transfer efficiency [18]-[20] for mobile applications.It is until recently that the dual use of RF signals for delivering energy as well as for transporting information has been advocated [21], [22]. Simultaneous wireless information and power transfer (SWIPT) [23] is proposed for delivering RF energy, usually in a low power region (e.g., for sensor networks). SWIPT provides the advantage of delivering controllable and efficient on-demand wireless information and energy concurrently, which offers a low-cost option for sustainable operations of wireless systems without hardware modification on the ...

Nonlinear code design for joint energy and information transfer

“…We consider an additive white Gaussian noise channel for which the input-output relationship is Y=X+z, (1) where X E {O, I} and Z is independent and identically distributed (ij.d.) Gaussian noise with zero mean and variance � o .…”

“…Potential applications of RF energy harvesting can be found in different areas including wireless sensor networks, wireless body networks and wireless charging systems [1].…”

Joint transfer of energy and information in a two-hop relay channel

“…The main characteristic of this setup is the sporadic nature of the harvested energy which makes the exact analysis rather difficult; (ii) in the second direction, known as Radio frequency (RF) energy harvesting, energy is harvested from the radio waves in space. This technique is promising with an increasing demand profile and some commercialized products [2]. Due to less randomness in obtaining the harvested energy, the analysis and strategies could be simpler compared with the harvesting from the environment.…”

Interference-Assisted Wireless Energy Harvesting in Cognitive Relay Network with Multiple Primary Transceivers

“…Besides harvesting energy from natural sources like solar and wind, nowadays, the radio environment can feed the energy in the form of radio-frequency (RF) signals [6]. Noticing that RF signals can carry both information and energy together, [7]- [9] have advocated the use of RF signals to harvest energy along with the information transmission.…”