Frequency Offset Estimation for High Dynamic LEO Satellite Communication Systems

In LEO satellite communication systems, satellites move at a speed of 7 km/s, resulting in a frequency offset of several hundred kHz. In LEO communication system, it has the characteristics of large frequency offset and fast change, wide range of SNR and small amount of training data. Based on ephemeris and terminal position information, this paper proposes a novel frequency offset estimation algorithm, which is composed of pre-compensation and fine estimation. Frequency offset precompensation is based on the position of terminal and ephemeris information of satellite, which can roughly compensate Doppler frequency offset caused by relative motion between them. For residual frequency offset, this paper proposes a fine estimation algorithm for LEO communication system. The impact of various system parameters on the estimation performance are discussed, including the number of training data, the frequency offset estimation range, selection of different symbol intervals of the training data and noise. This paper provides the corresponding adaptation algorithm. Finally, simulations are carried out to verify the effectiveness of the proposed algorithm.