Compensation of IQ imbalance using Kalman filter in coherent optical systems

This paper proposes a parametric network for the joint compensation of multiple linear impairments in coherent optical communication systems. The considered linear impairments include both static and time-variant effects such as in-phase/quadrature (IQ) imbalance, laser phase noise (PN), chromatic dispersion (CD), polarization mode dispersion (PMD), and carrier frequency offset (CFO). To jointly compensate for these considered impairments, the proposed network is composed of parametric layers that exploit the particular signal model of each impairment. The layers' parameters are jointly learned during a training stage. This stage uses a supervised step that exploits the knowledge of some transmitted data (preamble and/or pilots) and a self-labeling step that uses the knowledge of the symbol constellation. In addition, a new validation technique that does not require a different dataset is developed to avoid overfitting. The parametric network performance is compared to classical digital signal processing (DSP), and Deep Learning (DL) approaches using simulated data. Simulation results show that the proposed network outperforms the competing approaches in terms of Bit Error Rate (BER) while maintaining a relatively reduced computational complexity. In the scenarios considered, compared to the parametric network, the DSP approach introduces an OSNR penalty between 0.2 dB and 1.7 dB at a BER of 4 × 10 −3 . Furthermore, simulation results demonstrate that the proposed network is way more flexible than other approaches since it can easily be adapted to a different scenario and coupled with other techniques.

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“…where (µ, ν) ∈ C 2 . The impact of the IQ imbalance on the input signal can be modeled as follows [58], [59]:…”

Section: ) Laser Phase Noisementioning

confidence: 99%

A Parametric Network for the Global Compensation of Physical Layer Linear Impairments in Coherent Optical Communications

Frunza

Choqueuse

Morel

et al. 2022

IEEE Open J. Commun. Soc.

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“…These methods mainly focus on a few numbers of imperfections of the optical chain, employing local compensation techniques. Regarding the IQ imbalance, several approaches have been proposed for its compensation, including Gram-Schmidt orthogonalization procedure [11], ellipse correction [12], adaptive filtering [13]- [15], Kalman filtering [16], blind adaptive source separation [17], and machine learningbased [18]. Different techniques have also been proposed for IQ time skew estimation and compensation [19]- [22].…”

Section: Introductionmentioning

confidence: 99%

Global Estimation and Compensation of Linear Effects in Coherent Optical Systems Based on Nonlinear Least Squares

Frunza

Choqueuse

Morel

et al. 2022

IEEE Systems Journal

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This paper proposes a new estimation and compensation approach to mitigate several linear and widely linear effects in coherent optical systems using digital signal processing (DSP) algorithms. Compared to most of the available strategies that employ local estimation and/or compensation algorithms, this approach performs a global impairments estimation and compensation based on Nonlinear Least Squares. The proposed method estimates and compensates for the chromatic dispersion (CD), carrier frequency offset (CFO), in-phase/quadrature (IQ) imbalance, and laser phase noise (PN) in two steps. Firstly, it estimates the quasi-static parameters related to the CD, CFO, and both transmitter and receiver IQ imbalance. Secondly, it estimates both transmitter and receiver lasers' phases and compensates for all the imperfections by using a Zero-Forcing (ZF) equalizer. Simulations show the effectiveness of the approach in terms of statistical performance and computational time. The estimation performance is assessed by computing the Cramér Rao Lower Bound (CRLB), while the detection performance is compared to a modified Clairvoyant equalizer.

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A comparative study of adaptive and non-adaptive IQ imbalance compensation methods in RX system

Zekkari

Djendi

Guessoum

2019

2019 6th International Conference on Image and Signal Processing and Their Applications (ISPA)

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Compensation of IQ imbalance using Kalman filter in coherent optical systems

Cited by 4 publications

References 7 publications

A Parametric Network for the Global Compensation of Physical Layer Linear Impairments in Coherent Optical Communications

A Parametric Network for the Global Compensation of Physical Layer Linear Impairments in Coherent Optical Communications

Global Estimation and Compensation of Linear Effects in Coherent Optical Systems Based on Nonlinear Least Squares

A comparative study of adaptive and non-adaptive IQ imbalance compensation methods in RX system

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