In this paper, we investigate the impact of correlation between the energy and information links in wireless power transfer systems, from a physical layer security perspective. With that aim, we first determine how correlation can affect system capacity in practical energy harvesting set-ups. We quantify that even though link correlation improves the average signal-to-noise ratio (SNR) for a fixed transmit power, it also increases its variance, which ultimately degrades capacity. Based on this observation, we show that correlation between the energy and information links may be detrimental for the secrecy capacity in the legitimate high SNR regime, but beneficial in the low-SNR regime, whenever such correlation affects the legitimate user. Conversely, we also point out that when link correlation between the energy and wiretap links is rigorously accounted for, it barely affects secrecy performance, causing only a minor degradation in some instances.

中文翻译：

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安全无线供电通信中信息和能量链接之间相关性的影响

在本文中，我们从物理层安全的角度研究了无线电能传输系统中能量和信息链路之间相关性的影响。为此，我们首先确定相关性如何影响实际能量收集设置中的系统容量。我们量化了，即使链路相关性提高了固定发射功率的平均信噪比 (SNR)，它也会增加其方差，最终降低容量。基于这一观察，我们表明能量和信息链接之间的相关性可能对合法的高 SNR 体制中的保密能力有害，但在低 SNR 体制中有益，只要这种相关性影响合法用户。反过来，