短波突发通信中的 DFT 频偏估计算法

摘要

In this paper, a DFT-based frequency offset estimation algorithm is proposed.The study focuses on the fre-quency offset estimation in the shortwave burst-mode communication in combination with the time-bound characteris-tics of signal transmission and the characteristics of the channel with a low signal-to-noise ratio.A DFT( discrete Fou-rier transform) without padding zero was calculated in the coarse estimation.In the fine estimation, the iterative method was combined with the interpolation method to reduce the searching interval for obtaining the result.Error compensation was utilized to fix the bias of interpolation caused by low signal-to-noise ratio.The DFT without zero-padding results in less computational load in the coarse stage compared with the existing DFT algorithm.However, the iterative interpolation results in high search accuracy in the fine stage.Simulation results showed that under the condi-tion of low signal-to-noise ratios the proposed algorithm may approximate Cramer-Rao Lower Bound ( CRLB) theoreti-cal line and the estimation scope is wide.%针对短波突发通信中的频偏估计问题，结合信号传输的时限性以及低信噪比的信道特点，提出一种基于离散傅里叶变换（ DFT）的频偏估计算法。该方法首先利用非补零的DFT获取粗估计结果；精估计通过结合迭代与插值逐步缩小搜索区间来获取估计结果，并在迭代中引入误差补偿以修正低信噪比条件下的插值误差。与现有DFT类算法相比，该算法在粗估计中采用非补零DFT减小了计算复杂度，在精估计中迭代插值提高了搜索精度。仿真结果表明：在低信噪比条件下，该频偏估计算法可以逼近Cramer-Rao下界理论线，并有较宽的估计范围。