低信噪比动态时变信道中频移估计技术研究

ue to the Doppler effect, the difference in the transceiving oscillator, etc., there is always a certain frequency offset between the transceiving signals. The frequency offset will have a great influence on the demodulation and descrambling of wireless communication, and it will cause inter-symbol interference in the OFDM system. Therefore, we need to accurately estimate the frequency offset of the received signal for later compensation. Eliminate the effects of frequency offsets. With the increasing demand for communication technology and low signal-to-noise ratio, frequency shift estimation in dynamic time-varying channels has become a problem. This paper mainly compares and analyzes various frequency shift estimation methods, including time domain and frequency domain algorithms, based on data assisted and non-data assisted. The research algorithm can not achieve good results at the same time in accuracy and algorithm complexity. After comprehensive comparison, analysis and improvement, this paper proposes an algorithm integrating multiple FFT interpolation estimation methods. The simulation shows that the mean square error (MSE) of the frequency shift estimation of this algorithm is lower than 10-- under the condition of SNR as low as 0 db. 4, and will not cause a large fluctuation due to the change in the frequency offset value.