程序是OFDM系统整个发送接收过程，其中包含QPSK调制解调，快速傅里叶正逆变换，还有信道估计等过程。-The procedure is the OFDM transmitting and receiving process of the system, which includes QPSK modulation and demodulation, and inverse fast Fourier transform, and the channel estimation process.