多天线OFDM系统空时频分组码的性能分析

针对多天线正交频分复用系统空时频分组码，通过分析其成对错误概率的Chernoff边界，揭示了多径时延特征影响空时频分组码性能的根本原因，给出了在快衰落信道中空时频分组码设计方法。并在ITU-R M.1225建议的车载信道模型下，利用仿真评估了空时分组码、空频分组码和空时频分组码在快衰落信道中的性能。仿真结果表明，在快衰落信道中，空频分组码性能优于空时分组码；多径时延特征是设计适合快衰落信道中具有最大分集增益空时频分组码的关键因素。
关 键 词 正交频分复用; 空时分组码; 空频分组码; 多入多出

Abstract Union upper bound of pairwise-error-probability (PEP) for space-time/frequency block codes in multiple-antenna based orthogonal frequency-division multiplexing (OFDM) systems is derived. And new design considerations were revealed. Then performance comparison between space-frequency block (SFBC) codes, space-time block codes (STBC) and space-time-frequency block codes (STFBC)is performed at different throughput by link-level simulations. The results show that SFBC is superior to STBC in fast fading channel. And power-delay profile of fading channel should be considered for designs of space-time-frequency codes as well as channel orders. SFBC with 4 transmit antenna is robust to both vehicular A and B channel environment of ITU-R M.1225.
Key words orthogonal frequency-division multiplexing; space-time block codes; space-frequency block codes; multiple-input multiple-output