Joint carrier phase estimation and forward error correction
AssigneeTyco Electronics Subsea Communications LLC
InventorYi Cai
Life of this patent
Estimating the term…
Abstract
Methods and systems for processing an optical signal in a communication system are disclosed. The disclosed methods yield benefits for estimation and tracking of carrier phase of received signals at a digital coherent receiver without the use of differential coding. Specifically, phase ambiguity is removed by calculating the slope of the CPE at a location where the CPE begins to lose track of the received carrier phase signal. As such, a CPE offset adjustment may be applied in accordance with the calculated slope to reduce the number of ones and zeros corrected by a FEC decoder. Thus, the FEC aided CPE scheme may be a feed forward scheme that requires no training.
Claims18
A receiver utilized in an optical communication system comprising:
- a decision circuit for receiving an input signal and providing an output signal representing logic ones and zeros in response to a comparison of said input signal with a Carrier Phase Estimation (CPE) of said input signal;
- a forward error correction (FEC) decoder configured to decode said output signal and to provide feedback representative of the number of errors corrected by said FEC decoder and indicating a polarity of said input signal;
- and
- a CPE offset adjuster configured to adjust said CPE in response to said feedback to reduce a number of said ones and zeros corrected by said FEC decoder.
An optical communication system comprising:
- an optical signal transmitter comprising an encoder for encoding a binary data stream and a modulator for modulating said encoded binary data stream to produce an encoded optical signal;
- and
- an optical signal receiver for receiving said encoded optical signal, said optical signal receiver comprising:
- a demodulator for demodulating said encoded optical signal to provide an input signal;
- a decision circuit for receiving said input signal and providing an output signal representing logic ones and zeros in response to comparison of said input signal with a Carrier Phase Estimation (CPE) of said input signal;
- a Forward Error Correction (FEC) decoder configured to decode said output signal and to provide feedback representative of a number of errors corrected by said FEC decoder and indicating a polarity of said input signal;
- and
- a CPE offset adjuster configured to adjust said CPE in response to said feedback to reduce the number of said ones and zeros corrected by said FEC decoder.
A method for processing a received optical communication signal, comprising:
- receiving an input signal and providing an output signal representing logic ones and zeros in response to comparing said input signal with a Carrier Phase Estimation (CPE) of said input signal;
- decoding said output signal and providing a feedback representative of a number of errors corrected by a Forward error Correction (FEC) decoder and indicating a polarity of said input signal;
- and
- adjusting said CPE in response to said feedback to reduce the number of said ones and zeros corrected by said FEC decoder.
Dependencies are inferred from the claim text.