数字电视系统中OFDM稀疏信道估计算法

A Sparse Channel Estimation Algorithm for Digital Television OFDM Transmission Systems

针对采用OFDM调制技术的数字电视传输系统,利用信道的稀疏特性提出一种基于子空间拟合的信道估计算法。该算法首先利用参考矩阵列向量与观测向量的相关性来确定信道的非零抽头位置,然后再采用最小二乘算法完成对非零系数值的二次估计,避免了无谓的零抽头估计,改善了算法性能。在低信噪比和导频数较少的情况下,算法仍具有稳健的性能,仿真结果验证了该算法的有效性。

In this paper,a novel channel estimation algorithm is proposed based on matching pursuit idea for digital television OFDM transmission systems by exploiting the sparsity property of channel impulse response. Firstly ,the position of the nonzero tap coefficients are detected out by exploiting correlation between the column vector of direction matrix and the observation vector, and then the least square algorithm is developed to estimate the exact value of the nonzero coefficients,so as to improve the performance of the algorithm by avoiding estimating the zero coefficients. Under the circumstance of low SNR and small number of pilot symbols,the algorithm has a robust performance. Simulation results demonstrate the validity of the algorithm.