Systems and methods for identification and demodulation of complex signal formats

A method for autonomously determining the modulation format of an input signal, the method comprising:

• estimating the input signal's frame length to determine if the input signal's modulation format is conventional or time-domain hybrid;
• responsive to estimating the input signal's frame length, performing polarization scrambling mitigation on the input signal to generate a plurality of polarization demultiplexed signals, each of the plurality of polarization demultiplexed signals having a frame length equal to the estimated frame length of the input signal;
• responsive to determining the modulation format is time-domain hybrid, identifying a plurality of modulation formats that compose at least one of the plurality of polarization demultiplexed signals' frames;
• determining, based on the identified plurality of modulation formats, a ratio of a first modulation format to a second modulation format;
• and
• estimating, based at least in part on the ratio, a pattern arrangement of the plurality of modulation formats in time, the estimated pattern arrangement representative of a pattern arrangement of a frame of the input signal.

A method for autonomously determining the modulation format of an input signal, the method comprising:

• determining the input signal's baud rate;
• responsive to determining the baud rate of the input signal, estimating the input signal's chromatic dispersion (CD);
• compensating, based at least in part on the estimation of the input signal's CD, the input signal's CD to generate a CD-compensated signal;
• processing the CD-compensated signal to determine a number of multiplexed polarizations of the input signal;
• performing timing recovery on the CD-compensated signal to generate a timing-recovered signal representative of the input signal;
• estimating the input signal's frame length to determine if the input signal's modulation format is conventional or time-domain hybrid;
• responsive to determining the modulation format is time-domain hybrid, identifying a plurality of modulation formats that compose the input signal's frame;
• determining, based on the identified plurality of modulation formats composing the input signal's frame, a ratio of a first modulation format to a second modulation format;
• generating, based at least in part on the plurality of modulation formats composing the input signal's frame, the ratio, and the input signal's frame length, a plurality of reference signals having the same frame length and comprising the same plurality of modulation formats that compose the input signal's frame, in the same ratio;
• comparing higher-order statistics of the input signal to each of the reference signals;
• and
• selecting, from the plurality of reference signals, a particular reference signal in which a first error criterion based on higher-order statistics of the particular reference signal and higher-order statistics of the input signal is lower than a second error criterion based on the higher-order statistics of the input signal and higher-order statistics of any remaining reference signal.