An Efficient Blind Doppler Shift Estimation and Compensation Method for LEO Satellite Communications

Low earth orbit (LEO) satellite communication systems suffer a large and fast-varying Doppler shift which has to be estimated and compensated before any demodulation processing. In this paper, a novel Doppler shift estimation and compensation method is proposed. A cascading algorithm consisting of a time-vary Burg (TV-Burg) spectral analyzer and an alpha-beta filter is designed to provide a Doppler estimate at each sampling point recursively. Doppler compensation is then applied to each data sample using the corresponding estimate. The proposed method has the following two main characteristics. Firstly, neither satellite ephemerides nor training sequences is required for estimating the Doppler frequency. That is, it is a blind estimation method. Secondly, all processing units of this method are time-recursive, and they can update the outputs whenever a new data sample is received. As a result, the proposed method is able to track the fast time-varying Doppler shift continuously, thus reducing the processing budget at each sampling point and making it hardware-efficient. Simulation results demonstrate the effectiveness of the proposed method in a low SNR environment. Furthermore, the proposed method has been implemented on the Xilinx ZYNC-7100 FPGA and verified on a general-purpose