Abstract
Waveform design is a key technique to jointly exploit a beamforming gain, the channel frequency selectivity, and the rectifier nonlinearity, so as to enhance the end-to-end power transfer efficiency of wireless power transfer (WPT). Those waveforms have been designed, assuming perfect channel state information at the transmitter. This paper proposes two waveform strategies relying on limited feedback for multi-antenna multi-sine WPT over frequency-selective channels. In the waveform selection strategy, the energy transmitter (ET) transmits over multiple timeslots with every time a different waveform precoder within a codebook, and the energy receiver (ER) reports the index of the precoder in the codebook that leads to the largest harvested energy. In the waveform refinement strategy, the ET sequentially transmits two waveforms in each stage, and the ER reports one feedback bit indicating an increase/decrease in the harvested energy during this stage. Based on multiple one-bit feedback, the ET successively refines waveform precoders in a tree-structured codebook over multiple stages. By employing the framework of the generalized Lloyd's algorithm, novel algorithms are proposed for both strategies to optimize the codebooks in both space and frequency domains. The proposed limited feedback-based waveform strategies are shown to outperform a set of baselines, achieving higher harvested energy.
Original language | English |
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Article number | 8094952 |
Pages (from-to) | 415-429 |
Number of pages | 15 |
Journal | IEEE Transactions on Wireless Communications |
Volume | 17 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2018 Jan |
Bibliographical note
Funding Information:Manuscript received April 18, 2017; revised August 22, 2017; accepted October 18, 2017. Date of publication November 3, 2017; date of current version January 8, 2018. This work was supported by EPSRC of U.K. under Grant EP/P003885/1. The work of Y. Huang was supported by the China Scholarship Council Imperial Scholarship. The associate editor coordinating the review of this paper and approving it for publication was M. Kountouris. (Corresponding author: Bruno Clerckx.) The authors are with the Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, U.K. (e-mail: [email protected]; [email protected]).
Publisher Copyright:
© 2002-2012 IEEE.
Keywords
- Wireless power transfer
- limited feedback
- nonlinear model
- waveform optimization
ASJC Scopus subject areas
- Computer Science Applications
- Electrical and Electronic Engineering
- Applied Mathematics