关键词: 矩阵投影, 无线网络, 物理层, 安全, 多输入输出（MIMO）

Abstract: Because the physical layer of wireless communication lacks real shell protection, such as limited communication divergence of data transmission, content can be taken at the same time the listener and the eavesdropper, the purpose of this study lies in how to be wireless radio features as much as possible and improve the security performance of the wireless communication system as a whole, which is on the premise of the listeners can receive disrupt the eavesdropper information acquisition, both be short of one cannot. Most of the physical security method will be based on one or some hypothesis, some make assumptions to the position of the eavesdropper is limited, some assumption of signal attenuation level limit, although simplifies the analysis of the difficulty, but in the practical application often can't meet these assumptions, the safety of the actual situation to find a suitable for general scheme is imperative, this is the physical security research of the difficulty. Taking more into the system (MIMO) as the research basis, by many artificial noise by adding implementation method to improve security features, combined with the related knowledge of matrix projection in the matrix theory, realize the basic noise power allocation, complete the relevant simulation calculations, to improve the physical security of wireless network research purposes.

Key words: Matrix Projection, Wireless Networks, Physical Layer, Security, Multiple Input Multiple Output (MIMO)