Doppler shift robust receiver for mobile satellite communications

We propose an open-loop receiver performing simultaneous carrier phase estimation and symbol detection in Gaussian channels affected by large Doppler frequency shifts. The structure comprises a bank of nonlinear filters (one per digital symbol) that estimate the random component of the carrier phase, coupled with a Kalman-Bucy filter that estimates the Doppler shift, and a maximum likelihood decision algorithm. The receiver´s robustness allows to withstand large oscillator phase instabilities as well as significant carrier frequency offsets that characterize the communications with nonstationary satellites. Simulations performed with a binary digital phase modulation exhibit small frequency acquisition intervals which are essential in burst transmissions