Adaptive compensation method using the prediction algorithm for the Doppler frequency shift in the LEO mobile satellite communication system

In low earth orbit (LEO) satellite communication systems, more severe phase distortion due to Doppler shift is frequently detected in the received sig nal than in cases of geo-stationary earth orbit (GEO) satellite systems or terrestrial mobile systems. Therefore, an estimation of Doppler shift would be one of the most important factors to enhance performance of LEO satelli te communication system. In this paper, a new adaptive Doppler compensation scheme using location information of a user terminal and satellite, as wel l as a weighting factor for the reduction of prediction error is proposed. The prediction performance of the proposed scheme is simulated in terms of the prediction accuracy and the cumulative density function of the predicti on error with considering the offset variation range of the initial input p arameters in LEO satellite system The simulation results showed that the pr oposed adaptive compensation algorithm has the better performance accuracy than Ali's method, From the simulation results, it is concluded the adaptiv e compensation algorithm is the most applicable method that can be applied to LEO satellite systems of a range of altitude between 1,000 km and 2,000 km for the general error tolerance level, M = 250 Hz.