Iterative Feedforward Demodulation and Threshold Detection

Iterative demodulation and decoding has been introduced in 2005 by Colavolpe, Barbieri, and Caire to cope with channels affected by phase noise. However, iterations between the channel decoder and the demodulator increase system's complexity. In this letter, we propose an iterative carrier recovery scheme where the current iteration is based on the hard decisions taken after the previous iteration. The resulting algorithm is easy-to-implement and offers excellent phase noise tracking performance, as demonstrated by the numerical results presented in the letter that are obtained with phase noise generated by linewidths of practical interest and a highly spectral efficient modulation scheme as 256-QAM.