基于 MATLAB 对移动通信中的 BPSK、QPSK、16QAM 和 OFDM 基带传输系统进行仿真，分析它们在 AWGN 和 Rayleigh 信道下的误码率性能。重点建立了基于 QPSK 和 16QAM 调制方式下 OFDM 系统的仿真，比较两种调制方式在 Rayleigh 信道下的传输性能，分析了系统模型，提出了代码优化方案。(Based on MATLAB, we simulate the BPSK, QPSK, 16QAM and OFDM baseband transmission systems in mobile communications, and analyze their BER performance under AWGN and Rayleigh channels. The simulation of OFDM system based on QPSK and 16QAM modulation is mainly established. The transmission performance of two modulation modes under Rayleigh channel is compared, the system model is analyzed, and the code optimization scheme is put forward.)