Doppler Shift Estimation for Satellite Communications using Linear Estimators

Doppler shifts are an undesired effect that takes place in wireless signal transmission whenever there is relative movement between transmitter and receiver. In future communication generations, where low Earth orbit (LEO) satellites play a relevant role, such a phenomenon is expected to be strong with respect to satellites in higher altitudes, as LEO satellites travel at very high speeds. In this paper, we initially study this problem and propose a simple signal model to develop a standalone multi-step Doppler estimation approach based on linear estimators. Simulation results show practically unbiased estimates with variances close to the Cramer-Rao lower bound even in low signal-to-noise ratio regimes, demonstrating the potential of this technique in future non-terrestrial network systems.