Iterative carrier phase synchronization for low-density parity-check coded systems

In this paper, we consider the effect of a carrier phase offset on the performance of a low-density parity-check (LDPC) coded QAM modulated system. We investigate an ML-based carrier phase synchronization algorithm that makes use of the posterior probabilities of the data symbols, provided by the iterative decoder. The resulting carrier phase synchronizer is an extension, to LDPC coded systems, of the iterative phase estimator for turbo coded systems, presented in V.Lottici and M.Louse [2002], and has negligible BER performance degradation as compared to the ideally synchronized system.