说明：  进行OFDM系统的matlab仿真，其中采用的子载波数为8个。并且仿真了多普勒频移对OFDM的影响。基带调制采用QPSK
(Matlab simulation for OFDM system, which USES the subcarrier number is eight.And simulation of the doppler shift effect on OFDM.Baseband using QPSK modulation)