New joint algorithm of blind doppler parameters estimation for high-order QAM signals

Aiming at the difficulties of blind doppler parameters estimation for QAM signals in the satellite communication on-the-move (SCOTM) system, a new joint algorithm of blind doppler frequency and doppler-rate estimation based on cyclic-statistical tests and phase difference is proposed. By detecting one of the cyclic frequencies of QAM signals, located at the quartic frequency offset, doppler frequency is effectively estimated, meanwhile, the data division method is exploited to calculate the doppler-rate. Finally, phase lock loop (PLL) is proposed to make the estimation more accurately. All-sided Monte Carlo simulations are employed to confirm the theoretical analysis, simulation results indicate that this algorithm can track time-varying frequency of the QAM signals accurately.