RF-Based Energy Transfer Through Packets: Still a Dream? or a Dream Come True?

Kisong Lee,Jeonggil Ko

doi:10.1109/access.2019.2950711

Abstract

Limitations in battery capacity has held back the active development of novel applications for the Internet of Things (IoT) or have caused embedded systems researchers to design a number of “go-around” schemes, which sacrifice various system performance metrics for energy efficiency. However, with the concept of simultaneous wireless information and power transfer (SWIPT), many researchers accept it as a potential technology that can be the basis of designing various next-generation low-power embedded computing systems. This work presents an experimental validation on RF-based SWIPT techniques. Specifically, using the Powercast P2110 Powerharvester Receiver, we evaluate its potential of being applied to various low-power embedded applications. We analyze the performance of these commercially available energy harvesting RF receivers in packet-based networks to show that energy harvesting in such cases are only possible with packets of long lengths in practical environments. Furthermore, we experimentally show that despite carrying energy, external noise factors on the wireless channel can deteriorate the RF-based energy harvesting performance due to high voltage amplitude fluctuations. Based on such observations, we present a set of system-level suggestions for future SWIPT-based system development.

Highlights

In designing low-power embedded systems for various applications in different environments, minimizing the energy usage on the resource-limited computing platforms has been a long-time challenge for system designers
EMPIRICAL VALIDATION OF radio frequency (RF)-BASED ENERGY HARVESTING With the experimental configurations above, we present empirical results collected on the performance of RF-based energy harvesting for realizing simultaneous wireless information and power transfer (SWIPT)-oriented systems in packet-based wireless networks
SUGGESTIONS FOR FUTURE SYSTEM DESIGNS Based on our empirical results and our experimental experience, we present a set of practical suggestions for system designers that target to deploy RF-based energy harvesting and SWIPT technologies as part of their low-power wireless systems

Summary

INTRODUCTION

In designing low-power embedded systems for various applications in different environments, minimizing the energy usage on the resource-limited computing platforms has been a long-time challenge for system designers. 6(a) and 7), we can notice that despite the packet size and IPI both increasing the channel utilization, which increases the energy harvesting durations, for RF-based energy harvesting, the IPI has a heavier impact This behavior becomes prominent in the low IPI ranges by charging the capacitor more frequently by suppressing the capacitors energy dissipation; increasing the active duty-cycle and current supply levels super-linearly. With the interferer generating signals at a power much higher than the strength of the received signal from the transmitter (i.e., 12 dBm for the original signal and ∼18 dBm as the input power for the interference signal), we see a ∼26% reduction in the active duration and ∼23% loss in the supply power This result is somewhat unexpected given that interference RF is a form of RF energy and the RF-based energy harvesting module should be able to capture this as well. This suggests that if the incoming signal is disrupted due to external interference factors, the performance of a RF-based energy harvesting unit may not perform at its optimal

SUGGESTIONS FOR FUTURE SYSTEM DESIGNS

Findings

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