发表机构
CY Cergy Paris Université, ENSEA, CNRS; Barkhausen Institut, Dresden gGmbH（塞吉-巴黎大学，ENSEA，法国国家科学研究中心; 巴特豪森研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对近场冒充攻击下的物理层认证问题，推导了单/多天线攻击者的最优预编码方案，发现距离差异可阻止近场冒充攻击，验证了理论分析结果。
AI 中文摘要
本文研究近场场景下受冒充攻击的物理层认证（PLA）。与仅依赖到达角（AoA）的远场情况不同，近场中的导向矢量同时依赖于角度和距离。我们通过最小化合法发射方爱丽丝（Alice）的接收信号与主动攻击者伊芙（Eve）生成信号之间的均方误差（MSE）来分析攻击。对于单天线伊芙，我们推导了最优标量预编码器，并表明在标准二阶菲涅耳近似下，仅当伊芙与鲍勃（Bob）的角度和距离均与爱丽丝相同时，才可能实现完美冒充。随后我们将分析扩展至多天线伊芙，推导了最优预编码矢量，此情形下仅当爱丽丝的导向矢量属于伊芙导向矢量张成的子空间时，才可能实现完美冒充。仿真结果表明，近场中即使爱丽丝与伊芙的AoA相同，距离差异也足以阻止冒充攻击成功，验证了分析结果。
英文摘要
This paper studies physical-layer authentication (PLA) in the near-field regime under impersonation attacks. Unlike the far-field case, where the steering vector depends only on the angle of arrival (AoA), in the near field it depends on both angle and distance. We analyze the attack by minimizing the mean-square error (MSE) between the signal received from a legitimate transmitter Alice and the signal generated by an active attacker Eve. For a single-antenna Eve, we derive the optimal scalar precoder and show that, for an inter-element spacing no larger than half a wavelength and under the standard second-order Fresnel approximation, perfect impersonation is possible only if Eve has the same angle and the same distance from Bob as Alice. We then extend the analysis to a multi-antenna Eve and derive the optimal precoding vector. In this case, perfect impersonation is possible only if Alice steering vector belongs to the subspace spanned by Eve steering vectors. Simulation results show that, in the near field, a distance difference is sufficient to prevent a successful impersonation attack even when Alice and Eve have the same AoA, and confirm the analytical results.
