針對多天線正交頻分復(fù)用系統(tǒng)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(shè)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(jié)果表明，在快衰落信道中，空頻分組碼性能優(yōu)于空時分組碼；多徑時延特征是設(shè)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(guān)鍵因素。
關(guān) 鍵 詞 正交頻分復(fù)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