Huawei Technologies Co., Limited

Huawei Technologies Canada Co., Ltd.

Mrinmoy Jana

Jeebak Mitra

Lutz Hans-Joachim Lampe

Jin Wang

Zhuhong Zhang

Chuandong Li

Ahmed Mohamed Ibrahim Medra

Methods and systems for low complexity interference cancellation in multichannel optical transmission. Local or self-iteration is performed one or more times between an expected propagation decision feedback equalizer and a soft demapper. Following local iteration, a soft decision forward error correction decoder determines bit log-likelihood ratios, which are fed back to the expected propagation decision feedback equalizer and soft demapper for further self-iteration. Global iteration involving the decoder can also be performed one or more times before a bitstream is decoded.

System and method for interference cancellation in optical transmission

A receiver architecture is described for phase noise compensation in the presence of inter-channel interference (ICI) and inter-symbol interference (ISI), particularly for time-frequency packing (TFP) transmissions. The receiver includes a coarse phase noise (PN) estimator, a PN compensation module, an ICI cancellation module, an ISI compensation module, a FEC decoder, and an iterative PN estimator. The iterative PN estimator receives log likelihood ratio (LLR) information from the decoder and provides an iterative PN estimation to the PN compensation module. The decoder also provides LLR to the ISI compensation module, and to at least one other receiver for another subchannel that is immediately adjacent in frequency. The ICI cancellation module receives decoder output from at least one adjacent subchannel, which the ICI cancellation module uses to provide a ICI-cancelled signal.

Systems and methods for phase noise mitigation in optical superchannels

An interference mitigation apparatus, comprising: an adaptive feedforward filtering stage and an adaptive feedback filtering stage configured to produce a plurality of output signals from a plurality of frequency downconverted signals, the output signals for being provided to a data decoding stage; a plurality of phase rotators configured to apply phase rotation to the frequency downconverted signals prior to processing by the adaptive feedforward filtering stage and the adaptive feedback filtering stage; and an adaptive controller configured for varying an amount of the phase rotation applied by the phase rotators to the frequency downconverted signals based at least in part on symbol decisions made on the output signals. There may be second phase rotators configured to apply phase rotation after the adaptive feedforward filtering stage so as to produce the output signals for forwarding to the data decoding stage.

Methods and systems for interference mitigation in a dual-polarized communication system

Systems and methods of precoded faster than Nyquist (FTN) signalling are provided. In the transmitter, Tomlinson-Harashima Preceding (THP) is applied to produce precoded symbols. The THP is based on inter-symbol interference (ISI) due to using faster than Nyquist (FTN) signalling. An inverse modulo operation is not performed in the receiver. Instead, in the receiver, FTN processing is performed based on a matched filter output by determining log a-posteriori probability ratio LAPPR values computed for an nbit bof a kreceived symbol and pre-computed a-priori probabilities of an extended constellation for a given pulse shape h(t) and FTN acceleration factor combination.

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Mrinmoy Jana