Phase and Frequency Recovery Algorithms for Probabilistically Shaped Transmission

Barbosa, Fabio Aparecido; Rossi, Sandro; Mello, Darli A. A.

doi:10.1109/jlt.2019.2959395

Cited by 36 publications

(13 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this work, the training sequence is randomly generated. In practice, properly designed training sequence can potentially reduce its minimum required length to achieve the following: 1) Initialize the equalizer by applying the data-aided multimodulus algorithm (MMA) [66] 2) Obtain a coarse frequency offset (FO) using a peak search in the frequency domain of the signal y beat k = y train k • x * train k , where y train k is the received signal in the training period and x * train k is the complex conjugated training sequence [67].…”

Section: A Training Stagementioning

confidence: 99%

Probabilistic Shaping for the Optical Phase Conjugation Channel

Yankov

Hansen

Ros

et al. 2021

IEEE J. Select. Topics Quantum Electron.

View full text Add to dashboard Cite

Probabilistic constellation shaping is studied and developed for optical phase conjugation (OPC)-based nonlinearity compensation of Kerr nonlinearities in optical fiber links. The mid-link OPC scenario is considered for dispersion compensated systems. It is demonstrated in simulations and experimentally that transmission strategies optimal for classical additive white Gaussian noise (AWGN) channels can be sub-optimal for these systems without nonlinearity compensation. On the contrary, when nonlinearity compensation is applied with mid-link OPC, the channel noise is demonstrated to be Gaussian and AWGNlike transmission strategies thus remain effective. A channelagnostic probability mass function (PMF) optimization algorithm is proposed for the input constellation in order to further improve the shaping gains in both scenarios. Operating arbitrary PMFs on arbitrary channels is enabled by a channel-agnostic digital signal processing (DSP) chain. After ≈2000 km of transmission, mid-link OPC is demonstrated to provide ≈1 dB of gain in effective SNR, which translates to ≈0.4 bits/QAM symbol of gain in achievable information rate. The gain is then increased by an extra ≈0.2 bits/QAM symbol by applying probabilistic shaping.

show abstract

Section: A Training Stagementioning

confidence: 99%

Probabilistic Shaping for the Optical Phase Conjugation Channel

Yankov

Hansen

Ros

et al. 2021

IEEE J. Select. Topics Quantum Electron.

View full text Add to dashboard Cite

show abstract

“…where the logical equality follows from Bayes theorem. From (4) and (5) it follows that we have to find k such that:…”

Section: B Probability Aware Decision Regionsmentioning

confidence: 99%

Likelihood-Based Selection Radius Directed Equalizer With Time-Multiplexed Pilot Symbols for Probabilistically Shaped QAM

Rosa

Richter

2021

J. Lightwave Technol.

View full text Add to dashboard Cite

Probabilistically shaped (PS) quadrature amplitude modulation (QAM) recently established itself as the solution to adopt for state-of-the-art coherent transponders. This in turn has drawn attention to the rework of conventional digital signal processing (DSP) algorithms, which are not optimal for QAM-PS. In this context, we propose a novel pilot-aided equalization technique based on the ubiquitous radius directed equalizer (RDE). Our solution employs both payload and time-multiplexed pilot symbols for the adaptive filters update. The payload symbols are treated on the basis of the likelihood of their correct blind assignment. We show that this approach is at the same time able to reduce the global pilot overhead (POH) required by the DSP chain and to provide greatly improved performance in the tracking ability of the equalizer in the event of fast state of polarization rotations. We describe a simulation environment in which we model accurately static and dynamic polarizationrelated impairments. We test our algorithm over different shaped modulation formats and in the presence of transceiver impairments and demonstrate its superior performance with respect to standard feed-forward implementations in all the scenarios considered.

show abstract

“…P ROBABILISTIC shaping (PS) has gained increasing popularity in the last years, proving to provide superior performance for coherent transmission over an additive white Gaussian noise (AWGN) channel while enhancing at the same time the transmission rate flexibility. Nevertheless, the theoretical gain predicted with respect to unshaped quadrature amplitude modulation (QAM) is threatened by additional penalties arising from the digital signal processing (DSP) chain, whose adaptation to the peculiar symbol probability distributions of PS constellations is still an under-investigated topic [1]. The practical solutions implemented at the moment are (i) to use modulation-independent heavily pilot-based DSP [2] or (ii) to apply standard blind algorithms developed for unshaped M-QAM.…”

Section: Introductionmentioning

confidence: 99%

“…The former choice achieves the best flexibility but at the cost of a consistent reduction in the throughput due to the high pilot overhead (OH). On the contrary, the latter preserves the throughput but is a sub-optimal approach which can introduce consistent penalties [1], [3]. To solve this problem, blind PS-aware algorithms have been developed for polarization demultiplexing and equalization [3] and for frequency offset estimation [4] but, to the best of our knowledge, a PS-aware carrier phase recovery (CPR) has not been proposed yet.…”

Section: Introductionmentioning

confidence: 99%

“…Digital Object Identifier 10.1109/LPT.2020.3012970 modulations is represented by the blind phase search (BPS) algorithm [5]. Nevertheless, it has been extensively shown how the interplay between PS and BPS deteriorates the phase estimation, in particular for moderate to low signalto-noise ratio (SNR) [1]. Moreover, BPS is indisputably an heavily computationally expensive algorithm because of the high number of test rotations that are needed to be performed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Low Complexity Blind Carrier Phase Recovery for Probabilistically Shaped QAM

Rosa

Richter

2020

IEEE Photon. Technol. Lett.

View full text Add to dashboard Cite

We propose a novel two-stage blind carrier phase recovery scheme tailored for probabilistically shaped QAM. Our algorithm is based on modifying the classic Viterbi&Viterbi (V&V) and maximum likelihood (ML) phase estimators by optimizing the blind decisions over the received symbols taking into account the probability distribution of the received signal. Our technique improves the standard V&V + ML in all conditions and outperforms the state-of-the-art blind phase search (BPS) algorithm for a constellation entropy ≤4. At the same time our implementation preserves the low complexity of standard V&V + ML. This results in a remarkable reduction in complexity of up to a factor thirty compared to BPS.

show abstract

Phase and Frequency Recovery Algorithms for Probabilistically Shaped Transmission

Cited by 36 publications

References 29 publications

Probabilistic Shaping for the Optical Phase Conjugation Channel

Probabilistic Shaping for the Optical Phase Conjugation Channel

Likelihood-Based Selection Radius Directed Equalizer With Time-Multiplexed Pilot Symbols for Probabilistically Shaped QAM

Low Complexity Blind Carrier Phase Recovery for Probabilistically Shaped QAM

Contact Info

Product

Resources

About