Carrier frequency estimation in satellite communications

For the estimation of the carrier frequency shift in satellite communications using QPSK modulation, two methods are usually considered to eliminate the data modulation: multiplying the phase of the received samples by 4 and keeping their amplitude or setting it to unity. A study of the operating threshold of the carrier frequency estimation is carried out in both cases in the presence of additive white Gaussian noise. A technique based on the expectation of a noisy sample in each case is proposed and verified by simulation, with the help of an efficient algorithm for the frequency estimation. The application envisaged is the estimation of the carrier frequency in a satellite receiver in burst mode transmission