Waveform Design for Wireless Power Transfer
Waveform Design for Wireless Power Transfer
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DOI：
10.1109/tsp.2016.2601284
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发表时间：
2016-12-01
影响因子：
5.4
通讯作者：
Bayguzina, Ekaterina
中科院分区：
文献类型：
--
作者：
Clerckx, Bruno;Bayguzina, Ekaterina
近年来，远场无线电力传输技术（WPT）引起了广泛的关注。尽管进展迅速，但过去十年研究界的重点仍然主要集中在改进能量收集器（所谓的整流天线）的设计上，而忽略了发射机设计的影响。本文研究了发射波形的设计，以提高整流天线输出端的直流功率。我们推导了一个易于处理的非线性模型，并与传统文献中使用的线性模型进行了比较。然后，我们使用这些模型来设计自适应信道状态信息（CSI）的新型多正弦波形。有趣的是，线性模型倾向于窄带传输，将所有功率分配给单个频率，而非线性模型倾向于在多个频率上分配功率。通过实际仿真，基于非线性模型设计的波形比基于线性模型和非自适应波形设计的波形提供了显著的增益（就收获的直流功率而言）。我们还分析计算了各种波形的能量作为正弦波数和发射天线数的函数的理论标度定律。这些比例定律强调了CSI知识在WPT发射机中的好处，以及基于非线性整流天线模型而不是线性模型的WPT设计的好处。结果还激发了基于大规模多正弦多天线波形的WPT有前途的架构的研究。最后，结果强调了在任何涉及无线电源的系统设计中，对整流天线非线性建模和计算的重要性。
Far-field Wireless Power Transfer (WPT) has attracted significant attention in recent years. Despite the rapid progress, the emphasis of the research community in the last decade has remained largely concentrated on improving the design of energy harvester (so-called rectenna) and has left aside the effect of transmitter design. In this paper, we study the design of transmit waveform so as to enhance the dc power at the output of the rectenna. We derive a tractable model of the nonlinearity of the rectenna and compare with a linear model conventionally used in the literature. We then use those models to design novel multisine waveforms that are adaptive to the channel state information (CSI). Interestingly, while the linear model favours narrowband transmission with all the power allocated to a single frequency, the nonlinear model favours a power allocation over multiple frequencies. Through realistic simulations, waveforms designed based on the nonlinear model are shown to provide significant gains (in terms of harvested dc power) over those designed based on the linear model and over nonadaptive waveforms. We also compute analytically the theoretical scaling laws of the harvested energy for various waveforms as a function of the number of sinewaves and transmit antennas. Those scaling laws highlight the benefits of CSI knowledge at the transmitter in WPT and of a WPT design based on a nonlinear rectenna model over a linear model. Results also motivate the study of a promising architecture relying on large-scale multisine multiantenna waveforms for WPT. As a final note, results stress the importance of modeling and accounting for the nonlinearity of the rectenna in any system design involving wireless power.