Pilot-aided digital signal processing for reception of coherent optical communication

    公开(公告)号:US10594406B2

    公开(公告)日:2020-03-17

    申请号:US15916607

    申请日:2018-03-09

    Abstract: Pilot-aided digital coherent reception of high-order QAM signal detection using a continuous short pilot preamble and subsequent pilot symbols that are periodically distributed with payload data resulting in low-complexity and fast-convergence signal detection for continuous mode coherent reception of high-order QAM signals. A digital signal processor is configured to demodulate a transmitted data stream from digital stream of measurements of light mixtures produced in a receiver for coherent optical communications in response to receiving modulated optical carriers. The digital signal processor includes one circuit stage for providing corrections to the digital stream to compensate first effects on the light mixtures due to a frequency shift of a local optical oscillator of the receiver and another circuit stage for correcting the digital stream to compensate for second effects on the light mixtures due to polarization dependent channel modification of the modulated optical carriers.

    COHERENT OPTICAL RECEIVER FOR MEDIUM- AND SHORT-REACH LINKS

    公开(公告)号:US20190074908A1

    公开(公告)日:2019-03-07

    申请号:US15696939

    申请日:2017-09-06

    Abstract: A coherent optical receiver having an analog electrical circuit connected to combine the outputs of multiple photodetectors to generate an electrical output signal from which the data encoded in a received modulated optical signal can be recovered in a robust and straightforward manner. In an example embodiment, the analog electrical circuit includes one or more transimpedance amplifiers connected between the photodetectors and the receiver's output port. The coherent optical receiver may include a dual-polarization optical hybrid coupled to eight photodiodes to enable polarization-insensitive detection of the received modulated optical signal. The signal processing implemented in the analog electrical circuit advantageously enables the use of relatively inexpensive local-oscillator sources that may have relaxed specifications with respect to linewidth and wavelength stability. Different embodiments of the analog electrical circuit can be used to enable the receiver to receive amplitude- and intensity-encoded modulated optical signals.

    Forward error correction
    3.
    发明授权

    公开(公告)号:US12034620B2

    公开(公告)日:2024-07-09

    申请号:US16811405

    申请日:2020-03-06

    CPC classification number: H04L43/0847 G06F30/20 H03M13/1102 G06F2111/10

    Abstract: Various example embodiments for supporting forward error correction (FEC) in a communication system are presented. Various example embodiments for supporting FEC in a communication system may include selection of a FEC setting (e.g., an amount of puncturing and/or shortening of a FEC code, a FEC code, or the like) for a communication channel from a transmitter to a receiver based on channel characteristic information of the communication channel from the transmitter to the receiver (e.g., transfer function information, channel loss information, noise characteristic information, error information (e.g., bit error rate, error modeling, or the like), or the like). Various example embodiments for supporting FEC in a communication system, based on selection of a FEC setting for a communication channel based on channel characteristic information of the communication channel, may be applied within various types of communication systems, including various types of wired and/or wireless communication systems.

    FORWARD ERROR CORRECTION
    4.
    发明申请

    公开(公告)号:US20210281501A1

    公开(公告)日:2021-09-09

    申请号:US16811405

    申请日:2020-03-06

    Abstract: Various example embodiments for supporting forward error correction (FEC) in a communication system are presented. Various example embodiments for supporting FEC in a communication system may include selection of a FEC setting (e.g., an amount of puncturing and/or shortening of a FEC code, a FEC code, or the like) for a communication channel from a transmitter to a receiver based on channel characteristic information of the communication channel from the transmitter to the receiver (e.g., transfer function information, channel loss information, noise characteristic information, error information (e.g., bit error rate, error modeling, or the like), or the like). Various example embodiments for supporting FEC in a communication system, based on selection of a FEC setting for a communication channel based on channel characteristic information of the communication channel, may be applied within various types of communication systems, including various types of wired and/or wireless communication systems.

    CLOCK RECOVERY FOR BAND-LIMITED OPTICAL CHANNELS

    公开(公告)号:US20190334627A1

    公开(公告)日:2019-10-31

    申请号:US15966697

    申请日:2018-04-30

    Abstract: A coherent optical receiver in which the channel equalizer and the clock-recovery circuit are connected in a nested-loop configuration, wherein the channel estimate generated by the equalizer is used to adjust the phase of the clock signal generated by the clock-recovery circuit. The channel equalizer can be implemented using a bank of time-domain or frequency-domain FIR filters. In an example embodiment, the clock-recovery circuit is configured to track the phase rotation corresponding to the equalized signals in a frequency-dependent manner; track the phase rotation in the channel equalizer either in a frequency-dependent manner or based on the mean signal delay therein; and adjust the phase of the clock signal based on an effective difference between these two phase rotations. The clock-recovery circuit enhances the clock tone by applying a Fourier transform to the squared absolute values of the equalized signals outputted by the channel equalizer.

    Pilot-Aided Digital Signal Processing for Reception of Coherent Optical Communication

    公开(公告)号:US20190280778A1

    公开(公告)日:2019-09-12

    申请号:US15916607

    申请日:2018-03-09

    Abstract: Pilot-aided digital coherent reception of high-order QAM signal detection using a continuous short pilot preamble and subsequent pilot symbols that are periodically distributed with payload data resulting in low-complexity and fast-convergence signal detection for continuous mode coherent reception of high-order QAM signals. A digital signal processor is configured to demodulate a transmitted data stream from digital stream of measurements of light mixtures produced in a receiver for coherent optical communications in response to receiving modulated optical carriers. The digital signal processor includes one circuit stage for providing corrections to the digital stream to compensate first effects on the light mixtures due to a frequency shift of a local optical oscillator of the receiver and another circuit stage for correcting the digital stream to compensate for second effects on the light mixtures due to polarization dependent channel modification of the modulated optical carriers.

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