说明：  这里面有两个程序，两个都是采用4QAM调制。不过个人觉得第一个更容易懂，因为写的很有条理。我改的那个程序就是根据这个来的。 不过在这里面有个问题就是信道系数只能是由高到低，大家可以试试，改成[0.227 0.46 0.688 0.46 0.227]这个是老师给我的仿真中常用的信道系数，这个成为归一化信道，就是系数平方和为1. 第二个程序没有涉及到信道系数，但是这个程序当中，在128个子载波中，前后有32个空载波，这个在OFDM中也是经常用的，这样可以降低误码率。
(There are two procedures, both of them are used 4QAM modulation. But personally feel that a more easily understood, since they were written very structured. I changed that procedure is on the basis of the past. But in this there is a problem inside the channel coefficient is the only high to low, everyone can try, replaced by [0.227 0.46 0.688 0.46 0.227] This is the teacher for giving me frequently used in the simulation of channel coefficients, this has become normalized channel is the coefficient of the square and 1. The second procedure does not involve channel coefficient, but this process which, in the 128 sub-carrier, the before and after the air carrier has 32, this in OFDM is also frequently used, as this will reduce the misuse of rate.)