介紹了多入多出系統(tǒng)中的空時(shí)、空頻編碼技術(shù)，并在此基礎(chǔ)上將OFDM技術(shù)與MIMO系統(tǒng)相結(jié)合，研究了STBC-OFDM、SFBC-OFDM及VBLAST-OFDM系統(tǒng)。對(duì)該系統(tǒng)性能進(jìn)行了分析和仿真，結(jié)果表明VBLAST系統(tǒng)傳輸速率最高，其速率至少是分組碼MIMO-OFDM系統(tǒng)的2倍，但是其誤碼性能相對(duì)較差，誤碼率為0.001時(shí)，VBLAST-OFDM系統(tǒng)所需的信噪比比分組碼系統(tǒng)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.