在无线通信中，存在着严重的多径现象，能够引起严重的ISI。判决反馈均衡器（DFE）是目前最常用的一种消除ISI的均衡器。本程序使用Matlab实现的QPSK下的DFE。

OFDM is multicarrier modulation (MCM) technique [1] which provides an efficient means to handle high speed data streams on a multipath fading environment that causes ISI. Normally OFDM is implemented using FFT and IFFT’s. To decrease the BW waste