信道噪声实时产生算法及改进研究

针对经典的逆变换和舍弃法模拟信道噪声硬件实现复杂的问题，开发了一种基于谐波叠加(Sum of Sinusoids，SoS)中心极限理论和Hadamard矩阵变换相结合的改进方法实时产生高斯噪声，推导了该方法输出随机变量幅值的理论分布，分析了利用可编程逻辑器件(Field Programmable Gate Array，FPGA)硬件实现时，定点化位宽和查找表深度对输出精度和周期的影响。数值仿真表明，本文改进方法输出的幅值统计分布精度优于传统SoS方法，尾巴精确度有所提高，重复周期也大大扩展，可以满足实际中信道噪声硬件模拟的需求。 

Real-time generation method and its improvement for channel noises

Since the classical generation methods such as the inversion method and rejection method are very complicated in hardware implementation, we develop an improved method for reproducing Gaussian noises in real-time. The proposed method modified the Sum-of-Sinusoids (SoS) method based on the central limit theory by introducing the Hadamard matrix transformation. On this basis, the theoretical amplitude distribution of output random variables is derived, and by utilizing the field programmable gate array (FPGA) hardware, the effect of the width of fixed-point data and the depth of look-up tables on the distribution and periodicity of output variables was analyzed. Numerical simulation results show that the amplitude distribution of the new method obtains better precision than that of the traditional SoS method. In addition, the accuracy of the tail distribution and the repetition period are both improved significantly, which also shows the proposed method can meet the requirements of channel noise emulation in reality.