Performance of a waveform design for wireless power transfer with imperfect channel state information

Cantos, Luiggi; Sacarelo, Gerardo; Jeong, Yeonjin; Kim, Yun Hee

doi:10.1109/ictc.2017.8190925

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…Furthermore, based on the mentioned power-to-power and waveform-to-power rectifier models, the problem of waveform design with complete [33], [35], partial [36], [37], [38], [39], and no [40] knowledge of the channel state information (CSI) is available in the literature. In the case of a complete absence of CSI, the transmitter could resort to transmit diversity [40].…”

Section: B Literature Reviewmentioning

confidence: 99%

Practical Waveform-to-Energy Harvesting Model and Transmit Waveform Optimization for RF Wireless Power Transfer Systems

Ayir

Riihonen

Heino

2023

IEEE Trans. Microwave Theory Techn.

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The received radio-frequency (RF) power in farfield RF wireless power transfer (WPT)-with or without simultaneous information transfer-is minuscule due to large propagation loss in wireless media. In such scenarios, adapting to the receiver characteristics by transmit waveform optimization is essential for maximizing the harvested direct current (dc) and, thus, the end-to-end efficiency of an RF WPT system. The receiver efficiency in RF WPT is governed by the RF-to-dc efficiency of the rectifier as well as the impedance mismatch at the antenna and load. In this article, we study the receiver efficiency for any fixed load and, subsequently, present a novel rectifier model that relates the average harvested dc power to the distribution, that is, the histogram, of the instantaneous power levels of the RF signal's envelope over time. The proposed waveform-to-energy harvesting (EH) model enables us to anticipate the average harvested dc power for any waveform, including communication signals as well, given the knowledge of the powerlevel distribution. Consequently, we conduct rigorous waveform optimization to maximize the average harvested dc power and determine the digital baseband signal at the transmitter that does so, namely prove that a pulsed tone at appropriate frequency is optimal for RF WPT. We present a multiband test-bed for determining the receiver efficiency for any digital baseband waveform. The efficacy of the proposed model is corroborated through experiments as well as simulations, which confirm that it is operational as well as accurate in practice and that single-sine pulses yield higher efficiency than basic multisine waveforms, while a pulsed phase shift keying (PSK) is preferable for simultaneous wireless information and power transfer (SWIPT).

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Section: B Literature Reviewmentioning

confidence: 99%

Practical Waveform-to-Energy Harvesting Model and Transmit Waveform Optimization for RF Wireless Power Transfer Systems

Ayir

Riihonen

Heino

2023

IEEE Trans. Microwave Theory Techn.

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“…Moreover, there are major theoretical contributions on rectifier modeling, relying on approximations of the Shockley diode equation [20], [21] or data-based curve fitting [22] to mathematically characterize the nonlinearity of diodes. The idea of rectifier modeling has been further extended to address problems, such as waveform design under the availability of complete [20], [23] or limited [24], [25] knowledge of the channel state information (CSI).…”

Section: B Literature Reviewmentioning

confidence: 99%

Waveforms and End-to-End Efficiency in RF Wireless Power Transfer Using Digital Radio Transmitter

Ayir

Riihonen

Allén

et al. 2021

IEEE Trans. Microwave Theory Techn.

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We study radio frequency (RF) wireless power transfer (WPT) using a digital radio transmitter for applications where alternative analog transmit circuits are impractical. An important parameter for assessing the viability of an RF WPT system is its end-to-end efficiency. In this regard, we present a prototype test bed comprising a software-defined radio (SDR) transmitter and an energy-harvesting receiver with a low resistive load; employing an SDR makes our research meaningful for simultaneous wireless information and power transfer (SWIPT). We analyze the effect of clipping and nonlinear amplification at the SDR on multisine waveforms. Our experiments suggest that when the direct current (dc) input power at the transmitter is constant, high peak-to-average power ratio (PAPR) multisines are unsuitable for RF WPT over a flat-fading channel, due to their low average radiated power. The results indicate that the end-to-end efficiency is positively correlated with the average RF power of the waveform and that it reduces with increasing PAPR. Consequently, digital modulations, such as phase shift keying (PSK) and quadrature amplitude modulation (QAM), yield better end-to-end efficiency than multisines. Moreover, the end-to-end efficiency of PSK and QAM signals is invariant to the transmission bit rate. An in-depth analysis of the end-toend efficiency of WPT reveals that the transmitter efficiency is lower than the receiver efficiency. Furthermore, we study the impact of a reflecting surface on the end-to-end efficiency of WPT and assess the transmission quality of the information signals by evaluating their error vector magnitude (EVM) for SWIPT. Overall, the experimental observations of end-to-end efficiency and EVM suggest that, while employing an SDR transmitter with fixed dc input power, a baseband quadrature PSK signal is most suitable for SWIPT at large, among PSK and QAM signals.Index Terms-Nonlinear distortion, radio frequency (RF) energy harvesting (EH), simultaneous wireless information and power transfer (SWIPT), software-defined radio (SDR), wireless power transfer (WPT).

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“…Moreover, there are major theoretical contributions on rectifier modeling, relying on approximations of the Shockley diode equation [20], [21] or data-based curve-fitting [22] to mathematically characterize the non-linearity of diodes. The idea of rectifier modeling has been further extended to address problems like waveform design under the availability of complete [20], [23] or limited [24], [25] knowledge of the channel state information (CSI).…”

Section: B Literature Reviewmentioning

confidence: 99%

Waveforms and End-to-End Efficiency in RF Wireless Power Transfer Using Digital Radio Transmitter

Ayir¹,

Riihonen²,

Allén³

et al. 2020

Preprint

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Performance of a waveform design for wireless power transfer with imperfect channel state information

Cited by 5 publications

References 8 publications

Practical Waveform-to-Energy Harvesting Model and Transmit Waveform Optimization for RF Wireless Power Transfer Systems

Practical Waveform-to-Energy Harvesting Model and Transmit Waveform Optimization for RF Wireless Power Transfer Systems

Waveforms and End-to-End Efficiency in RF Wireless Power Transfer Using Digital Radio Transmitter

Waveforms and End-to-End Efficiency in RF Wireless Power Transfer Using Digital Radio Transmitter

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