天线相关条件下空频码的分集特性分析

Diversity Character Analysis of Space-frequency Coding Under Antenna Correlation

已有空频码设计的文献分析了在天线不相关假设下一个MIMO-OFDM系统的最大分集阶数,而在实际系统中,发送端和接收端的天线之间的相关性总是很难避免的,已经有理论分析指出这种天线相关性将最终影响系统容量,但并没有明确指出相关性对系统分集特性的影响。通过一种等效的信号模型,通过该模型将频率选择性衰落信道下系统的分析等效为平衰落信道下的分析,并导出了存在天线相关情况下码字的成对错误概率,并通过对码字成对错误概率的分析给出了存在天线相关情况下系统能提供的最大分集阶数以及码设计的一些特性。

The existing papers have analyzed the maximum diversity order of a MIMO-OFDM system under the assumption of no spatial fading correlations. In a practical system, the spatial correlation always exists between the transmitter and receiver antennas. Theoretical analysis has confirmed that it will reduce the system capacity but it does not point out its impact to the diversity order of a practical system. A modified signal model was provided, which transformed the transmission in frequency selective channels into fiat fading channels and an asymptotic analysis of the performance was proposed under the assumption of correlated antennas： Based on the performance analysis, some diversity character analysis of space-frequency coding with antennas correlations was proposed.