The simulation results show that no matter which channel model is chosen, the low-modulation can always achieve a better performance in high SNR region. Moreover, we conclude that coding and interleaving techniques can also considerably improve the performance of the system. 2. 实验结果表明:无论选用何种信道模型,在高信噪传输条件下,低阶调制方式能够为系统提供良好的性能保障,而编码和交织技术的应用可观地改善了系统的性能。