一种改进的基于DFT的OFDM信道估计算法

传统的DFT信道估计算法计算复杂度比MMSE算法低,性能比LS算法好。但是它只消除了信道冲击响应中循环前缀长度之外的噪声,而循环前缀长度以内的噪声并没有进行任何抑制,从而影响了算法的性能,说明性能存在提高的空间。对传统的DFT信道估计算法略加改进,仅仅在循环前缀长度内引入阈值门限,通过阈值门限进行阈值处理,就可以进一步消除噪声的影响。仿真表明：改进后的算法性能明显优于原算法,具有很好的实用价值。

An Improved OFDM Channel Estimation Algorithm Based on DFT

Traditional DFT-based channel estimator for OFDM systems has lower computational complexity than MMSE channel estimators, and better performance than LS channel estimators. However, the traditional DFT-based channel estimator removes only the noise in the channel impulse response （CIR） beyond the length of the cyclic prefix （CP）, while the noise within the length of CP is not suppressed at all, affecting the performance of the algorithm, and indicating that there is certain space for improving its performance. The traditional channel estimator is fairly improved and proposed. Only by introducing a decision threshold into the length of CP, the influence of the noise could be further removed by threshold processing. Simulation results show that the improved algorithm is superior to the original algorithm, and thus is of practical application value.