利用PN码的循环相关性进行信道估计时,其估计值是有偏的,并且在低信噪比下受信道噪声的影响大。鉴于此,提出了基于信道噪声功率估计的FMT无偏信道估计算法,利用估计值数据特点,完全消除了残余直流偏置,同时在接收端利用导频序列估计信道噪声功率,根据路径信噪比选择出受噪声干扰大而能量贡献小的多径分量并将其置零,降低了信道噪声对估计精度的影响,改善了信道估计性能。 When the channel estimation is performed by using the cyclic correlation of the PN code, the estimation value is biased and is greatly affected by the channel noise at a low signal-to-noise ratio. In view of this, an FMT unbiased channel estimation algorithm based on channel noise power estimation is proposed. By using the characteristics of the estimated data, the residual DC offset is completely eliminated, and the channel noise power is estimated at the receiving end by the pilot sequence. The multi-path component which is influenced by noise interference and has small energy contribution is selected and set to zero, which reduces the influence of channel noise on the estimation accuracy and improves the channel estimation performance.