OFDM系统中一种新的迭代信道估计算法  

A New Iterative Channel Estimation for OFDM System

作　　者：张晓瀛[1] 魏急波[1] 

机构地区：[1]国防科技大学电子科学与工程学院,湖南长沙410073

出　　处：《信号处理》2007年第2期227-230,共4页Journal of Signal Processing

摘　　要：本文提出了OFDM系统中一种新的基于软信息迭代处理的信道估计算法。该算法将面向判决最小二乘估计算法和盲估计算法相结合,在估计器中构造了一种新的置信度量函数,根据解码和软映射重构的反馈信号置信度大小在两种估计算法中自适应选择,这样估计的信道频响可以有效提高软信息迭代接收性能,大大降低信道估计训练开销。仿真结果表明,本文提出的算法能有效跟踪信道时变,限制传统面向判决估计的错误传播,达到好的系统性能。In this paper,we propose a new channel estimator based on iterative soft information processing. The algorithm combines the decision-directed LS algorithm and the blind estimation algorithm. A new reliability measurement function is constructed in the estimator. Based on the reliability factor of the feedback signal which is reconstructed by the decoder and soft-mapping, an option is made adaptively between two estimation algorithms. The channel response from the estimator can improve the performance of the iterative receiver with soft information, reduce the training overhead for channel estimation significantly. Simulation results show that the proposed algorithm can track the time-varying channel efficiently, limit the conventional decision-directed estimation＇ s error spread, and achieve good system performance.

关 键 词：EM算法 BCJR算法 SISO(软入软出) LS(最小二乘算法) 

分 类 号：TN948.14[电子电信—信号与信息处理]