一种基于匹配追踪的OFDM稀疏信道估计算法

An OFDM Sparse Channel Estimation Algorithm Based on Matching Pursuit

针对OFDM系统,利用信道冲激响应的稀疏特性,提出了一种新的OFDM信道估计算法。首先利用匹配追踪思想确定出非零抽头系数的位置,然后再采用最小二乘算法完成对非零系数值的二次估计,从而通过减少信道估计参数的个数降低算法复杂度。在低信噪比和导频数较少情况下,该算法具有良好的归一化均方误差性能,特别是当因信噪比低而引起GAIC算法性能恶化的时候,新算法具有更好的稳健性。仿真结果验证了算法的有效性。

In this paper, a novel OFDM channel estimation algorithm is proposed by exploiting the sparsity property of channel impulse response. Firstly, the matching pursuit idea is used to detect the position of the nonzero tap coefficients. Secondly, the least square algorithm is utilized to estimate the exact value of the nonzero coefficients, so as to reduce the computation complexity of the algorithm by decreasing the numbers of the channel parameters being estimated. This algorithm has good NMSE performance under the circumstance of low SNR and small number of pilot symbols. Compared with GAIC algorithm, it also has much better robust performance under the low SNR circumstance. Simulation results demonstrate the validity of the algorithm.