Phase Noise-Robust LLR Calculation with Linear/Bilinear Transform for LDPC-Coded Coherent Communications

We propose a modified log-likelihood ratio (LLR) calculation for an LDPC decoder to be ro-bust against residual phase noise at the demodulator. The proposed scheme is based on a lin-ear/bilinear transform offers 1-2dB gain in the presence of large phase noise. Conference on Lasers and Electro-Optics (CLEO