适用于OFDM系统的改进的信道估计算法  

An improved channel estimation method for OFDM systems

作　　者：陈拿权[1] 张建华[1] 张平[1] 

机构地区：[1]北京邮电大学电信工程学院,北京100876

出　　处：《高技术通讯》2008年第8期783-789,共7页Chinese High Technology Letters

基　　金：863计划(2006AA01Z283;2006AA01Z260);国家自然科学基金(60302025)资助项目

摘　　要：针对实际系统中的信道)中激响应(CIR)泄漏问题,提出了一种适用于梳状导频正交频分复用(OFDM)系统的改进的最小二乘(LS)信道估计算法。该算法基于分数抽头延时信道近似(FTCA)的参数化信道模型,此信道模型采用一个抽头间隔为分数倍采样间隔的抽头延时线结构的有限冲激响应(FIR)滤波器表示。此算法首先通过 FTCA 信道模型来近似实际信道,然后再估计该信道模型中的某些参数来获取实际的信道信息;该算法利用了 FTCA 信道模型中所有的延时抽头,从而很好地抑制了 CIR 泄漏。仿真与分析表明,FTCA 信道模型能够有效地近似实际信道,同时降低信道自相关矩阵的维数,从而提高信道估计的性能。In order to lessen the severe effects of the channel impulse response （CIR） leakage in practical orthogonal frequency .division multiplexing （OFDM） systems, an improved least square （LS） channel estimation algorithm was proposed, which could be adopted in OFDM systems based on comb-type pilot arrangement. The algorithm was based on a parametric channel approximation model, which was called the fraction taps channel approximation （FTCA） channel model and was modeled as a finite impulse response （FIR） on some definitive delay taps that had a fraction tap delay spacing relative to the sampling interval. In the algorithm, the real channel was first approximated by the FrCA channel model and then the channel information was well achieved by the estimate of the channel parameters in the FlEA channel model. The proposed algorithm well suppressed the CIR leakage because it used all these delay taps in the FI＇CA channel model. Through simulations and analyses, it is proved that the FTCA channel model could effectively approximate the real channel and reduce the dimension of the channel covariance matrix, and consequently, improve the channel estimation performance .

关 键 词：正交频分复用(OFDM) 分数延时抽头信道近似(FrCA) 信道估计 信道冲激响应泄漏 

分 类 号：TN919.3[电子电信—通信与信息系统]