Carrier recovery scheme for on-board demodulation suited to low E b/N0

In this paper we describe and analyse new feedforward synchronization algorithms suited to on-board digital implementation. Both algorithms studied here (for phase and frequency recovery) have the particularity to perform all calculations in polar coordinates and so to reduce complexity of implementation. A phase estimator operating at very low SNR with no frequency offset is defined. Its performances are close to the Viterbi and Viterbi algorithm. A frequency estimator based on the previous phase estimator is also presented and analysed