梳状导频的OFDM信道估计改进算法

摘要

研究提高正交频分复用系统(OFDM)中信道估计的准确度问题,由于在无线信道中存在频率衰落,造成估计误差.针对实际系统中的信道冲激响应(CIR)泄露问题,用传统分数抽头延时信道(FTCA)的信道模型进行信道估计是一种很好的方法.但是,基于FTCA的信道估计算法需要的已知条件过多,实用性很差.为此提出了一种较为实用的梳状导频MMSE准则的信道估计算法,首先获取导频位置的LMMSE信道估计,然后利用FTCA变换获得所有子载波的信道传递函数.实验证明,改进算法在降低计算量的同时,获得了接近LMMSE算法的性能,提高了系统的频谱效率和估计精度.%In order to lessen the effects of the channel impulse response leakage in OFDM systems and improve the accuracy of the channel estimation of OFDM system, a channel model called FTCA was used to estimate the channel of OFDM. But the channel estimation algorithm based on FTCA channel model is not practical because it needs to generate the auto—covariance matrix. In this paper, a new channel estimation algorithm was proposed based on comb -type pilot in OFDM systems. Based on traditional MMSE channel estimation methods, we obtained all the transfer function of all the carriers. The performance was proved to work much better than LrMMSE channel estimation with the same difficulty. The efficiency of OFDM systems is also improved.