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为了消除正交频分复用(OFDM,Orthogonal Frequency Division Multiplexing)符号定时偏差对信道估计的影响,提出了一种补偿算法.理论分析表明相移可以被看作是信道统计特性的变化,并且在使用线性插值的信道估计方法时估计误差会扩大.该算法利用符号定时偏差会引起子载波相位旋转的特点,对信道估计进行补偿.仿真结果表明,在多径信道下,在信噪比为20 dB定时位置位于循环前缀中点时,使用该算法后信道估计均方误差是通常线性插值算法的25%,因此新算法缩小了信道估计均方误差.实验结果表明,该算法提高了接收机的性能.
In order to eliminate the influence of Orthogonal Frequency Division Multiplexing (OFDM) symbol timing offset on channel estimation, a compensation algorithm is proposed, and theoretical analysis shows that phase shift can be regarded as the change of statistical characteristics of channel. The estimation error increases when using the linear interpolation channel estimation method.This algorithm utilizes the characteristic that the symbol timing deviation will cause the phase rotation of the subcarriers to compensate the channel estimation.The simulation results show that under the condition of multipath channel, When the dB timing position is at the midpoint of the cyclic prefix, the mean square error of the channel estimation after using this algorithm is 25% of that of the usual linear interpolation algorithm, so the new algorithm reduces the mean square error of the channel estimation.The experimental results show that this algorithm improves the receiver’s performance.