Patent ID: 9596035
Date: 2017-03-14
CPC Classifications: H04B

Claim:
1. In a coherent receiver of an optical communications system, a method of data symbol recovery comprising: periodically computing, by a frequency error estimator, a local slope representative of at least a frequency offset between a local oscillator of the receiver and a transmitter laser; computing, by a phase noise estimator, probabilistic phase error estimates based on the computed local slope and data symbol estimates detected from a received optical signal, the probabilistic phase error estimates being representative of a phase error of each data symbol estimate and a probability that each data symbol estimate is in a correct decision region of a symbol constellation; and computing by a phase rotator a phase rotation by applying a predetermined filter function to a plurality of the probabilistic phase error estimates, and applying the computed phase rotation to at least one data symbol estimate to generate a corresponding rotated symbol estimate.