采用重要性采样的方法来代替蒙特卡罗仿真方法，确定数字通信系统的BER。重要性采样方法可以简单的增加信道噪声的方差，等效于使系统工作在一个较低的信噪比的环境下。-Using importance sampling method to replace the Monte Carlo simulation method to determine the digital communication system BER. Importance sampling method can be a simpl

64QAM基带系统接收机matlab代码：添加AWGN噪声，进行接收端匹配滤波器，8倍下采样，解调信号。-64QAM baseband system receiver matlab code: add AWGN noise, matched filter receiving end, eight times the down-sampling, the demodulated signal.

OFDM在多普勒信道下的仿真，包括扩频调制、上变频、升采样等-OFDM in the Doppler channel simulation, the module is full