Iterative detection of CO-OFDM signals with phase errors using circular random variables

We propose a low-complexity graph-based iterative algorithm for the detection of coherent optical OFDM signals in the presence of residual carrier frequency offset and phase noise. We exploit the circular properties of the frequency offset and phase noise and derive graphical messages using the Gaussian probability density function. The proposed algorithm shows similar error rate performance as the existing algorithm at a much lower implementation complexity.