Huawei Technologies Co., Limited

Hossein Najafi

Zhuhong Zhang

Chuandong Li

Jeebak Mitra

Mahdi Zamani

Ahmed Mohamed Medra

Demin Yao

Ahmed Mohamed Ibrahim Medra

Ali Bakhshali

Jin Wang

Xuefeng Tang

Meng Qiu

The disclosed systems and methods for frequency domain (FD) local oscillator frequency offset (LOFO) compensation. The method comprising: i) compensating, by an integer Fast Fourier Transform (FFT) bins-based oscillator, LOFO in a received signal by an integer number of FFT bins; and ii) compensating, by a fractional FFT bins-based oscillator, LOFO in the compensated signal by the integer FFT bins-based oscillator with a fine compensation resolution of a fractional number of FFT bins.

Systems and methods for frequency domain local oscillator frequency offset compensation

The disclosed systems and methods for compensating the polarization dependent loss (PDL) in communication networks comprising: i) filtering, by a first feed-forward filter, a current set of symbols in an equalized X-Pol signal; ii) filtering, by a second feed-forward filter, a current set of symbols in an equalized Y-Pol signal; iii) filtering, by a first feed-backward filter, a previously decided set of symbols associated with the equalized X-Pol signal; iv) filtering, by a second feed-backward filter a previously decided set of symbols associated with the equalized Y-Pol signal; v) adding, by a first adder, the outputs from the first feed-forward filter and the second feed-forward filter; and vi) subtracting, by the first adder, the outputs from the first feed-backward filter and the second feed-backward filter from the addition of outputs from the first feed-forward filter and the second feed-forward filter to determine the symbols in the equalized X-Pol signal.

Systems and methods for compensating polarization dependent loss (PDL) in dual polarized communication network

The disclosed systems and methods are directed to transmitting and receiving symbols. In particular, splitting, a symbol dataset into symbol subsets, modulating, the symbol subsets using different sub-carriers, roll off factors and time acceleration factors, performing frequency shifting and combining the frequency shifted and modulated symbol subsets to generate a digital multiband (DMB) signal, transmitting and receiving the DMB signal, down converting the received DMB signal into a plurality of baseband signals, segregating the plurality of baseband signals in accordance with a manner by which the symbol subsets have been processed before transmission, forwarding a first portion of the plurality of baseband signals to a minimum mean square error (MMSE) based receiver, forwarding a second portion of the plurality of baseband signals to a matched filter-based receiver, and combining the output of the MMSE based receiver and matched filter-based receiver to generate an equivalent symbol dataset.

System, method and apparatus for Multi-Band Faster-than-Nyquist scheme-based communication

Apparatus and methods are provided for noise-whitening post-compensation in a receiver. A first apparatus includes a first whitening filter configured to filter a received signal comprising symbols to generate a first filtered signal. The first apparatus further includes a first decision feedback equalizer having an input coupled to an output of the first whitening filter to receive the first filtered signal. The first decision feedback equalizer is configured to apply decision feedback equalization to the first filtered signal to generate estimates for the symbols of the received signal. A second apparatus includes a decision device configured to generate a symbols decision based on a received signal comprising symbols, a noise predictor configured to predict noise in the received signal, and a subtractor configured to subtract the predicted noise from the received signal to generate a symbols estimate.

Efficient implementation of noise whitening post-compensation for narrowband-filtered signals

Aspects of the present disclosure are directed in part to a receiver DSP unit including an equalization module. The equalization module includes a trellis-based equalization module that may utilize multiple trellis-based processors (TBP), which can each be individually adaptively configured for performing a trellis-based equalization. The design of the TBPs allows them to be configured for compensating a residual Inter-Symbol Interference (ISI) as well as compensating a residual Phase Noise (PN). ISI is an example of an additive impairment and PN is an example of a multiplicative impairment that communication systems, particularly high speed transmission systems such as coherent optical systems, can suffer from.

Trellis based processing for robust digital multiband transmission

A symbol detection and forward error correction (FEC) decoding system and method are disclosed that aim to increase decoding performance and maintain an acceptable level of complexity. In one embodiment, the method includes performing detection and decoding over a plurality of iterations. During the first iteration: a first equalizer structure processes a received signal, and a FEC decoder performs decoding on an input obtained from the output of the first equalizer structure. During the other iterations: an iterative equalizer structure processes both (i) the received signal and (ii) an input obtained from an output of the FEC decoder from a previous iteration of the detection and decoding, in order to generate an output of the iterative equalizer structure, and the FEC decoder performs FEC decoding on an input obtained from the output of the iterative equalizer structure.

System and method for turbo equalization and decoding in a receiver

A digital signal processing method and apparatus is described. The digital processing apparatus comprises a coarse carrier recovery module for performing a coarse carrier compensation of a received modulated signal; and a trellis-based equalization module selectable between a first mode for performing a trellis-based equalization to compensate a residual inter-symbol interference of the received modulated signal and a second mode for performing a trellis-based equalization to compensate a residual phase noise of the received modulated signal.

Apparatus and method for unified mitigation of correlative additive and multiplicative noise

A method and apparatus for performing residual phase noise compensation is described. A coarse carrier compensation of a received modulated signal is performed to obtain a coarse carrier compensated signal and a trellis-based residual carrier recovery is performed to estimate a residual phase noise of the coarse carrier compensated signal. The coarse carrier compensated signal is compensated based on the estimated residual phase noise.

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Kanata, Canada

Hossein Najafi