In this study, a spatial spectrum method is proposed to cope with the pilot spoofing attack (PSA) problem by exploiting the of uplink–downlink channel reciprocity in time-division-duplex multiple-input multiple-output systems. First, the spoofing attack in the uplink stage is detected by a threshold derived from the predefined false alarm based on the estimated spatial spectrum. When the PSA occurs, the transmitter (That is Alice) can detect either one or two spatial spectrum peaks. Then, the legitimate user (That is Bob) and Eve are recognized in the downlink stage via the channel reciprocity property based on the difference between the spatial spectra if PSA occurs. This way, the presence of Eve and the direction of arrival of Eve and Bob can be identified at the transmitter end. Because noise is suppressed by a spatial spectrum, the detection performance is reliable even for low signal-noise ratios and a short training length. Consequently, Bob can use beamforming to transmit secure information during the data transmission stage. Theoretical analysis and numerical simulations are performed to evaluate the performance of the proposed scheme compared with conventional methods.

中文翻译：

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MIMO系统中导频欺骗攻击检测的空间谱方法

在这项研究中，提出了一种空间频谱方法，通过利用时分双工多输入多输出系统中的上下行信道互易性来应对导频欺骗攻击（PSA）问题。首先，上行链路阶段的欺骗攻击是通过基于估计的空间频谱的预定义虚警得出的阈值来检测的。当 PSA 发生时，发射机（即 Alice）可以检测到一个或两个空间频谱峰值。然后，合法用户（即 Bob）和 Eve 在下行链路阶段通过基于空间频谱之间的差异的信道互易性（如果 PSA 发生）被识别。这样，就可以在发射端识别 Eve 的存在以及 Eve 和 Bob 的到达方向。因为噪声被空间光谱抑制，即使对于低信噪比和短训练长度，检测性能也是可靠的。因此，Bob 可以在数据传输阶段使用波束成形来传输安全信息。进行理论分析和数值模拟，以评估与传统方法相比所提出方案的性能。