非合作通信中一种高精度载频估计算法

A High-precision Carrier Frequency Estimation Algorithm in Noncooperative Communication

为实现非合作通信中信号载频的精确估计,提出一种与频偏估计相结合的载频估计算法。该算法首先利用改进的频率居中法粗估计信号载频,之后根据载频粗估计值对信号下变频,利用下变频后信号的自相关函数提取载频估计偏差,最后根据频偏估计结果对载频粗估计结果进行补偿即可得到精确的载频估计值。仿真结果表明,在没有任何先验信息的情况下,该算法可以实现对ASK、PSK与QAM信号载频的精确估计,且在低信噪比情况下仍能保持良好的估计性能。

In order to realize accurate estimation of signal carrier frequency in non-cooperative communication,a carrier frequency estimation algorithm combined with frequency offset estimation is proposed.Firstly,the algorithm uses the improved frequency centering method to roughly estimate the signal carrier frequency.Then,the signal is down-converted according to the rough estimated value of the carrier frequency,and the auto-correlation function of the down-converted signal is used to extract the carrier frequency estimation deviation.Finally,by compensating the rough carrier frequency estimation result according to the frequency offset estimation result,an accurate carrier frequency estimation value can be obtained.The simulation results indicate that without any prior information,the algorithm can accurately estimate the carrier frequency of ASK,PSK and QAM signals,and it can still maintain good estimation performance in the case of low SNR.