Carrier phase recovery for turbo-coded linear modulations

In this paper, we present a low-complexity carrier phase estimation algorithm suited for turbo-coded 16-QAM modems. The estimator is based on a maximum likelihood (ML) approach, and unlike previously published work, makes iterative use of soft decisions provided by the soft-in soft-out decoders within the overall iterative turbo decoding scheme, yielding negligible degradation with respect to ideal phase synchronization. Performance in terms of mean estimated value, mean-squared estimation error, and overall decoder bit error rate (BER) as derived by simulation are also reported.