空时分块编码OFDM系统的Turbo均衡

研究了空时分块编码的OFDM（正交频分复用）系统，对系统进行了Turbo均衡，并讨论了此时系统的译码算法和均衡算法。系统信道编码采用Turbo码，通过对BCJR（Bahl，Cocke，Jelinek，Raviv）算法的简单修改得到SISO（单输入单输出）MAP（最大后验概率）译码算法；均衡器采用SISOMMSE（最小均方差）Turbo均衡算法，并利用OFDM系统的循环前缀特性进一步降低算法复杂度。通过仿真对系统性能进行了比较分析，仿真结果表明，采用迭代均衡的空时分块编码OFDM系统性能要明显优于未空时编码和未迭代均衡的OFDM系统。

Turbo Equalization of a Space-time Block-coded OFDM System

In this paper, a space-time block-coded OFDM system has been studied, and Turbo equalization is applied to the system, and its decoding algorithm and equalization algorithm have been discussed. The system is channel-coded by Turbo code, its SISO MAP decoding algorithm is inferred by simple modifying the BCJR algorithm. SISO MMSE Turbo equalization algorithm is applied to equalizing section, and the characteristics of OFDM cyclic prefix reduced the complexity of equalization further. The system performance has been analyzed by computer simulation. The simulation results show that a space-time block-coded OFDM system with Turbo equalization performs much better than a OFDM system without being space-time block-coded or Turbo equalized.