OFDM技术关键实现的C代码，包括FFT、QPSK、星座变换等。-The OFDM technology critical to achieve the C code, including FFT, QPSK, Constellation transform.

此程序模拟了一个基本的OFDM通信系统，采用16QAM调制，并绘出了星座图及输入输出信号频谱-This program simulates a basic OFDM communication system using 16QAM modulation, and draw a constellation diagram and the input and output signal spectrum