Article
Engineering, Electrical & Electronic
Vincent Lauinger, Fred Buchali, Laurent Schmalen
Summary: In this study, the potential of adaptive blind equalizers based on variational inference for carrier recovery in optical communications is investigated. The introduction of variational autoencoder (VAE) equalizers and the analysis of their performance and flexibility show that this approach is effective in improving the performance of blind adaptive equalizers.
IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Pedro J. Freire, Yevhenii Osadchuk, Bernhard Spinnler, Antonio Napoli, Wolfgang Schairer, Nelson Costa, Jaroslaw E. Prilepsky, Sergei K. Turitsyn
Summary: The study compared the performance and complexity of different artificial neural networks for nonlinear channel equalization in coherent optical communication systems. The CNN+biLSTM architecture showed the largest Q-factor improvement and was the best option when computational complexity was not constrained. However, when complexity was restricted to lower levels, the three-layer perceptron performed best.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Computer Science, Information Systems
Agustin C. Galetto, Benjamin T. Reyes, Damian A. Morero, Mario R. Hueda
Summary: This work introduces an adaptive background compensation scheme for frequency interleaved DACs, improving the system performance in high-speed communication applications. Through elaborate digital signal processing, seamless synthesis of signals in the reconstructed output is achieved, enhancing the performance of communication systems and manufacturing yield.
Article
Engineering, Electrical & Electronic
Yi Cai, Hungchang Chien, Meng Xiang, Wei Wang, Fan Li, Zihe Hu, Mingyi Gao, Chenxu Jiang, Zhongxing Tian, Hansheng Xu, Kaisheng Zhang, Jiaojie Shen, Ji Huang
Summary: The key idea of this work is to treat the symbol-pattern-dependent inter-symbol-interference as useful symbol correlation and upgrade the system to a multi-symbol-oriented pattern-dependent equalization and detection regime. The proposed adaptive equalization scheme can be applied to various transmission systems with linear or nonlinear pattern-dependent ISI, and effective demodulation and detection are demonstrated in experimental coherent transmission systems.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Akira Kawai, Masanori Nakamura, Minami Takahashi, Takayuki Kobayashi, Yutaka Miyamoto
Summary: In this article, we propose partially frozen (PF) multiple-input multiple-output (MIMO) adaptive equalizers (AEQs). These AEQs can cope with various signal impairments that occur within a transmitter and receiver, such as in-phase/quadrature (IQ) skew and IQ imbalance. By reducing effective degrees of freedom (DOFs) and freezing unnecessary updates, PF MIMO AEQs can track polarization fluctuations efficiently in a dynamic environment, increasing the information rate of transmissions. Numerical simulations and experiments demonstrate the effectiveness of PF MIMO AEQs in high-speed data transmissions.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Jianghao Li, Christina Lim, Ampalavanapillai Nirmalathas
Summary: This paper investigates the performance of two popular adaptive equalization methods in the indoor optical wireless communication system using few-mode based uniform beam shaping. The results show that the multi-equalizer scheme achieves better equalization performance and higher convergence speed than the single-equalizer scheme, with a similar computational complexity. The recursive least-square method has a higher convergence speed than the least mean square method, while the least mean square method has a lower computational complexity under the same desired equalization performance.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Telecommunications
Mohammed J. Khafaji, Maciej Krasicki
Summary: In this paper, a novel uni-cycle Genetic Algorithm (GA) is proposed to optimize the coefficients of an adaptive linear equalizer. Unlike traditional GAs, this algorithm takes into account the continuous changes in channel state, and demonstrates superior convergence properties and tracking capability.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Physics, Fluids & Plasmas
Kunal Pal, Kuntal Pal, Tapobrata Sarkar
Summary: In this study, the Nielsen circuit complexity of coherent spin state operators is calculated. The complexity expression is derived using the small angle approximation of the Euler angle parametrization. The results are extended to systems with time evolutions generated by external field couplings and nonlinearly interacting Hamiltonians. The relationship between Nielsen complexity and squeezing parameters, as well as pairwise entanglement, is investigated. The difficulty with this approach for the Lipkin-Meshkov-Glick model is identified and resolved by computing the complexity using the Tait-Bryan parametrization.
Article
Telecommunications
Lianyou Jing, Han Wang, Chengbing He, Yang Zhang, Hongxi Yin
Summary: The study proposes a solution to the interference issues in OTFS modulation, combating interference with a 2D adaptive multichannel DFE. The proposed equalizer constructs input and feedback signals based on the characteristics of OTFS modulation, and utilizes the sparse features of channels in the delay-Doppler domain, employing the IPNLMS algorithm for fast convergence and tracking.
IEEE COMMUNICATIONS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Kwangho Lee, Hyojun Kim, Woosong Jung, Jinhyung Lee, Haram Ju, Kwanseo Park, Ook Kim, Deog-Kyoon Jeong
Summary: This research presents the design of a low-power receiver with an adaptive equalizer and an offset cancellation scheme. The proposed AOC engine and shared-half rate structure help achieve a BER of less than 10(-12) in a wide range of data rates. The prototype chip consumes 18.6 mW at 10 Gb/s and exhibits a figure-of-merit of 0.068 pJ/b/dB.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2021)
Article
Telecommunications
Minhao Zhang, Yifan Wang, Xingbin Tu, Fengzhong Qu, Hangfang Zhao
Summary: The adaptive minimum symbol error rate (AMSER) equalizer is superior to the adaptive minimum mean square error equalizer in symbol error rate (SER) performance. Furthermore, the normalized AMSER (NAMSER) equalizer outperforms the AMSER equalizer by incorporating the minimum SER (MSER) criterion. Inspired by this, the researchers propose an improved recursive least squares-based NAMSER equalizer (RLS-NAMSER) that takes advantage of the faster convergence of the RLS algorithm compared to the NLMS algorithm. Simulation results show that the RLS-NAMSER equalizer has better convergence performance while maintaining nearly the same steady state performance as the NAMSER equalizer.
IEEE COMMUNICATIONS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
James J. W. Kunst, Juan I. Bonetti, Benjamin T. Reyes, Damian A. Morero, Mario R. Hueda
Summary: Coherent transceivers with high data rates in the Terabit-per-second range and beyond are required for next generation optical communications. Precompensation of transmitter imperfections such as time skew, amplitude and phase errors is proposed in this work using a novel and efficient technique. The scheme is adaptive and can adjust to time and environment dependent impairments in real-time without interrupting normal operation. The proposed scheme only requires low bandwidth information from the transmitter output, providing a meaningful advance compared to usual channel estimation methods.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Etsushi Yamazaki, Shinya Sugiura
Summary: This paper proposes a receiver architecture that can compensate for time-varying signal distortion caused by transmitter analog components. The proposed architecture includes a novel transmitter distortion compensating (TDC) block implemented outside the feedback control loop to reduce feedback delay. The simulation results show significant reduction in the required signal-to-noise ratio penalty, and theoretical analysis confirms the impact of feedback delay on the tracking speed of the receiver.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Computer Science, Information Systems
Le Wang, Mo Zhou, Zhenxing Niu, Qilin Zhang, Nanning Zheng
Summary: This paper introduces a continuous variable model to capture the relevance degree between queries and multiple candidates, and proposes to learn a coherent embedding space where candidates with higher relevance degrees are mapped closer to the query. A new ladder loss is proposed to implement variable push-away margins based on relevance degrees, and a Silhouette score-based method is proposed to adaptively decide the ladder level. Extensive experiments show that the proposed method outperforms existing state-of-the-art methods.
IEEE TRANSACTIONS ON MULTIMEDIA
(2023)
Article
Engineering, Civil
Jacob Rudander, Thor Husoy, Paul A. A. van Walree, Pal Orten
Summary: This article presents a FPGA-based multihydrophone receiver and assesses its real-time performance in different shallow-water channels. The receiver, incorporating an integer precision multichannel linear equalizer, utilizes the Least Mean Squares Algorithm for tap updates. By employing a 64-hydrophone line array in the very high-frequency band, it achieves data rates of up to 465 kb/s over 100 m and 155 kb/s over 1000 m.
IEEE JOURNAL OF OCEANIC ENGINEERING
(2023)
