Another turbo-something : Carrier synchronization

We introduce in this paper a low-complexity joint carrier frequency and phase recovery algorithm for coherent detection/decoding of a turbo-coded 16-QAM signal. The estimator (which can be actually applied to any linear modulation scheme) is based on a pseudo-Maximum Likelihood (ML) approach, and unlike previously published works, makes iterative use of soft decisions provided by the SISO (Soft-In Soft-Out) decoders within the overall iterative turbo decoding scheme, yielding negligible degradation with respect to ideal carrier 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.