中文说明： 仿真结果和分析 QPSK 调制在瑞利衰落信道下的性能。 该代码清楚解释，它可以被理解的帮助下注释行
English Description：
The simulation and analysing the performance of QPSK modulation in rayleigh fading environment. The code is explained clearly and it can be understood with the help of comment lines