Waveform Design for Wireless Power Transfer With Limited Feedback
Waveform Design for Wireless Power Transfer With Limited Feedback
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DOI：
10.1109/twc.2017.2767578
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发表时间：
2017-04
影响因子：
10.4
通讯作者：
Yang Huang;B. Clerckx
中科院分区：
文献类型：
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作者：
Yang Huang;B. Clerckx
波形设计是联合利用波束形成增益、信道频率选择性和整流器非线性以提高无线功率传输（WPT）的端到端功率传输效率的关键技术。这些波形已经被设计，假设完美的信道状态信息在发射机。针对频率选择性信道下的多天线多正弦WPT，提出了两种基于有限反馈的波形策略。在波形选择策略中，能量发送器（ET）在多个时隙上发送，每次在码本内使用不同的波形预编码器，并且能量接收器（ER）报告码本中导致最大收获能量的预编码器的索引。在波形细化策略中，ET在每个阶段中顺序地发送两个波形，并且ER报告一个反馈比特，该反馈比特指示在该阶段期间所收集的能量的增加/减少。基于多个一比特反馈，ET在多个阶段上连续地细化树结构码本中的波形预编码器。通过采用广义劳埃德算法的框架，新的算法提出了这两种策略，以优化码本在空间和频率域。所提出的基于有限反馈的波形策略表现出优于一组基线，实现更高的收获能量。
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.