电子学报 ›› 2006, Vol. 34 ›› Issue (10): 1881-1883.

• 论文 • 上一篇    下一篇

OFDM系统中基于软信息处理的自适应双模半盲信道估计

张晓瀛, 魏急波   

  1. 国防科技大学电子科学与工程学院军事通信系,湖南长沙 410073
  • 收稿日期:2005-09-05 修回日期:2006-08-20 出版日期:2006-10-25 发布日期:2006-10-25

An Adaptive Dual Mode Semi-Blind Channel Estimation Based on Soft Information Processing for OFDM Systems

ZHANG Xiao-ying, WEI Ji-bo   

  1. Institute of Electronic and Engineering,National University of Defense Technology,Changsha,Hunan 410073,China
  • Received:2005-09-05 Revised:2006-08-20 Online:2006-10-25 Published:2006-10-25

摘要: 本文提出了一种新的基于软信息迭代处理的自适应双模半盲信道估计算法.该算法构造了新的置信度量函数获取译码和软映射重构的反馈信号的置信度,和置信阈值比对后在判决反馈和盲估计两种估计模式之间自适应选择,这样估计的信道频响可以提高软信息迭代接收的性能.仿真结果表明,本文提出的算法能综合两种估计模式的优势,限制传统判决反馈模式的错误传播,在没有分散导频辅助估计的条件下有效跟踪时变信道,达到好的系统性能.

关键词: 面向判决(Decision directed), EM算法, BCJR算法, LS算法(最小二乘算法)

Abstract: In this paper,we propose a new adaptive dual mode semi-blind channel estimator based on iterative soft information processing.A new reliability measure function is constructed to calculate the reliability factor of the reconstructed signal from the decoder and soft mapping.An option is made adaptively between the decision directed mode and blind estimation mode by comparing the reliability factor with a specified threshold.The estimated channel frequency response can improve the performance of the iterative receiver.Simulation results show that the proposed algorithm combines the two algorithms’ advantages and limits the conventional DD mode’s error propagation.It can track the time-varying channel efficiently without scattered pilots and achieve good system performance.

Key words: DD(decision directed), BCJR algorithm, EM algorithm, least square algorithm

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