基于软反馈的BDFE Turbo均衡  

Block decision feedback equalizer with soft feedback for Turbo equalization

作　　者：窦高奇[1] 刘宏波[1] 高俊[1] 陶伟[2] 

机构地区：[1]海军工程大学电子工程学院,湖北武汉430033 [2]海军装备研究院,北京100161

出　　处：《系统工程与电子技术》2011年第6期1392-1396,共5页Systems Engineering and Electronics

基　　金：国防预研基金(101030603)资助课题

摘　　要：通过分析指出线性最小均方误差均衡器采用独立高斯分布假设计算的符号后验概率(a posteriorprobability,APP)值过大,造成译码反馈信息不足。提出了采用软反馈的块判决反馈均衡器(block decision feed-back equalizer,BDFE)来弥补高斯分布假设在计算符号APP时的不足,并推导了软符号后验均值的计算公式。采用软反馈降低原BDFE采用硬反馈带来的错误扩散,同时与序列检测相结合,提高了均衡器APP估计的可靠性。仿真结果验证了该方法在相近复杂度情况下均衡性能的优越性。By analyzing the probability density function（PDF） evaluated with independent Gaussian assumption for the linear minimum mean square error（LMMSE） equalizer,the conclusion that the a posterior probability（APP） evaluation with independent Gaussian assumption is larger than the true value is obtained,which results in the deficiency of decoder extrinsic information.To offset the shortcoming for computing symbol APP with independent Gaussian assumption,the soft feedback block decision feedback equalizer for Turbo equalization is proposed and the formula of the soft symbol posterior mean is derived.The adoption of symbol posterior mean based soft feedback reduces the error propagation in the sequence-based block decision feedback equalizer（BDFE） with hard feedback and supplies more reliable information with sequence detection for APP evaluation.Simulation results validate the superiority of the proposed method with similar complexity.

关 键 词：TURBO均衡 块判决反馈均衡器 后验概率 软反馈 序列检测 

分 类 号：TN911.5[电子电信—通信与信息系统]