This paper investigates physical layer security (PLS) in wireless interference networks. Specifically, we consider confidential transmission from a legitimate transmitter (Alice) to a legitimate receiver (Bob), in the presence of non-colluding passive eavesdroppers (Eves), as well as multiple legitimate transceivers. To mitigate interference at legitimate receivers and enhance PLS, artificial noise (AN) aided interference alignment (IA) is explored. However, the conventional leakage minimization (LM) based IA may exhibit confidential signal cancellation phenomenon. We theoretically analyze the cause and then establish a condition under which this phenomenon will occur almost surely. Moreover, we propose a means of avoiding this phenomenon by integrating the max-eigenmode beamforming (MEB) into the traditional LM based IA. By assuming that only statistical channel state informations (CSIs) of Eves and local CSIs of legitimate users are available, we derive a closed form expression for the secrecy outage probability (SOP), and establish a condition under which positive secrecy rate is achievable. To enhance security performance, an SOP constrained secrecy rate maximization (SRM) problem is formulated and an efficient numerical method is developed for the optimal solution. Numerical results confirm the effectiveness and the usefulness of the proposed approach.

翻译：本文研究无线干扰网络中的物理层安全（PLS）问题。具体而言，我们考虑在存在非共谋被动窃听者（Eves）以及多个合法收发设备的情况下，合法发射机（Alice）到合法接收机（Bob）的机密传输。为减轻合法接收机处的干扰并增强PLS，探索了人工噪声（AN）辅助的干扰对齐（IA）技术。然而，基于传统泄漏最小化（LM）的IA可能产生机密信号抵消现象。我们从理论上分析其成因，并确立了该现象几乎必然发生的条件。此外，我们提出通过将最大本征模态波束赋形（MEB）融入传统LM型IA来避免该现象。在仅掌握Eves的统计信道状态信息（CSI）与合法用户的本地CSI的假设下，推导出了保密中断概率（SOP）的闭式表达式，并建立了可达到正保密率的条件。为提升安全性能，构建了SOP约束的保密率最大化（SRM）问题，并开发了高效数值方法以求解最优方案。数值结果验证了所提方法的有效性与实用性。