針對多天線正交頻分復用系統空時頻分組碼，通過分析其成對錯誤概率的Chernoff邊界，揭示了多徑時延特征影響空時頻分組碼性能的根本原因，給出了在快衰落信道中空時頻分組碼設計方法。并在ITU-R M.1225建議的車載信道模型下，利用仿真評估了空時分組碼、空頻分組碼和空時頻分組碼在快衰落信道中的性能。仿真結果表明，在快衰落信道中，空頻分組碼性能優于空時分組碼；多徑時延特征是設計適合快衰落信道中具有最大分集增益空時頻分組碼的關鍵因素。
關 鍵 詞 正交頻分復用; 空時分組碼; 空頻分組碼; 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