In recent research, non-orthogonal artificial noise (NORAN) has been proposed as an alternative to orthogonal artificial noise (AN). However, NORAN introduces additional noise into the channel, which reduces the capacity of the legitimate channel (LC). At the same time, selecting a NORAN design with ideal security performance from a large number of design options is also a challenging problem. To address these two issues, a novel NORAN based on a pilot information codebook is proposed in this letter. The codebook associates different suboptimal NORANs with pilot information as the key under different channel state information (CSI). The receiver interrogates the codebook using the pilot information to obtain the NORAN that the transmitter will transmit in the next moment, in order to eliminate the NORAN when receiving information. Therefore, NORAN based on pilot information codebooks can improve the secrecy capacity (SC) of the communication system by directly using suboptimal NORAN design schemes without increasing the noise in the LC. Numerical simulations and analyses show that the introduction of NORAN with a novel design using pilot information codebooks significantly enhances the security and improves the SC of the communication system.

翻译：近期研究中，非正交人工噪声(NORAN)被提出作为正交人工噪声(AN)的替代方案。然而，NORAN会向信道引入额外噪声，导致合法信道(LC)容量下降。同时，如何从大量设计方案中选取具有理想安全性能的NORAN设计也是一个极具挑战性的问题。为解决上述两个问题，本文提出一种基于导频信息码本的新型NORAN方案。该码本将不同信道状态信息(CSI)下的次优NORAN与作为密钥的导频信息相关联。接收端通过查询导频信息对应的码本，获取发射端下一时刻将发送的NORAN，从而在接收信息时消除该NORAN。因此，基于导频信息码本的NORAN可直接采用次优NORAN设计方案，在不增加LC噪声的前提下提升通信系统的保密容量(SC)。数值仿真与分析表明，采用导频信息码本创新设计的NORAN可显著增强系统安全性，并有效提升通信系统的保密容量。