| The broadband LEO(Low Earth Orbit Satellite) mobile communication system becomes a significant component for the air-space-ground integrated information network, and plays an important role for providing to mobile terminal use. The bandwidth resources of the LEO satellite are inefficient, which deals with the frequency selectivity and channel fading characteristic.The special transmission technique needs counteract anti-channel frequency selective fading, which has high bandwidth utilization efficiency. Therefore OFDM(Orthogonal Frequency Division Multiplexing) for broadband LEO satellite mobile communication is an important researched topic for improving system performance.OFDM is researched for broadband LEO communication system, which mainly focuses on the following aspects.Firstly, the channel statistical property for LEO satellite has been proposed. Research based on broadband LEO satellite communication system has been researched. According to channel characteristic, analysis shows compariso, anti-Doppler shift, anti-AWGN(Additive White Gaussian Noise) channel, which proves that OFDM transmission technique is suitable for the broadband LEO satellite communication system.Secondly, The larger frequency offset destroys the orthogonality of LEO system. For tradition cancellation algorithms is high, and frequency offset scope which can be captured is low. TF-RLS(Time and Frequency Domain Least Mean Square) algorithm has been proposed, which cancels the interference that is introduced by large frequency offset with low complexity.Thirdly, broadband LEO link transmission system has been firstly established based on TF-RLS algorithm, which combined with AMC(Adaptive Modulation and Coding). Analysis of OFDM transmission technique for broadband LEO communication system has been given. Compared with MF-TDMA(Muti-Frequency Time Division Multiple) transmission technique, OFDM is superior in broadband LEO satellite. |
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