说明：  1.用基带等效的方式仿真16-QAM在AWGN信道下的误码率和误比特率性能，并与理论值相比较； 2.高阶64QAM与低阶16QAM的性能比较。
(1. The BER and BER performance of 16-QAM in AWGN channel is simulated by baseband equivalent method, and compared with the theoretical value; 2. Performance comparison between high-order 64QAM and low-order 16QAM.)