介绍了多入多出系统中的空时、空频编码技术，并在此基础上将OFDM技术与MIMO系统相结合，研究了STBC-OFDM、SFBC-OFDM及VBLAST-OFDM系统。对该系统性能进行了分析和仿真，结果表明VBLAST系统传输速率最高，其速率至少是分组码MIMO-OFDM系统的2倍，但是其误码性能相对较差，误码率为0.001时，VBLAST-OFDM系统所需的信噪比比分组码系统要高9.3 dB。This paper introduces the space-time coding and the space-frequency coding technologies of a Multi-Input and Multi-Output(MIMO) system. We combine the Orthogonal Frequency divided Multiplex (OFDM) with MIMO system and research on several MIMO-OFDM systems, for example, Space-Time Block Coding (STBC) OFDM system, Space-Frequency Block Coding(SFBC) OFDM system, and Vertical Bell Laboratories Layered Space Time (VBLAST)-OFDM system. Analysis and simulation of these MIMO-OFDM systems’ performance are examined. The results show that the data rate of the VBLAST-OFDM system is the highest, which is at least the twice as high as that of the STBC-OFDM or SFBC-OFDM system. However Bit Error Rate(BER) performance of the VBLAST-OFDM system is worse than that of the others. When BER is equal to 0.001, the required signal-noise ratio for VBLAST-OFDM system is 9.3dB more than that for the STBC or SFBC and OFDM system. On the other hand, the complexity of the VBLAST-OFDM system is higher than that of the STBC or SFBC and OFDM systems.