Weighted OFDMA time-frequency synchronization for space solar power LEO satellites networks: Performance and cost analysis

This paper introduces a novel time and frequency synchronization technique for space solar power (SSP) satellite networks accomplished by weighted OFDMA sub-carrier training signal scheme. Exploiting OFDMA sub-carriers allows controlling the training signal bandwidth, which reduces the signal dispersion effects imposed by atmospheric layers. Here, we propose the procedure of estimating the weights for each OFDMA subcarrier that optimize an objective function key to the coarse time synchronization. Once time synchronization is complete, the carrier frequency offset that is due to the Doppler effect due to the movement of satellites is estimated exploiting the recursive least square (RLS) algorithm considering unknown channel impulse response (CIR). Analytical and simulation results confirm that the proposed scheme attains fast convergence, high stability, and ideal performances when compared to the relevant Cramer-Rao lower bounds in all ranges of signal-to-noise ratio.