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Experimental demonstration of modified constant modulus algorithm with polarization demultiplexing in Stokes space in optical coherent receiver

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OPTICS COMMUNICATIONS 2025年 583卷

作者： Huang, Bohang Dong, Xiangyong Shi, Fengjie Yu, Zhenming Xu, Kun Beijing Univ Posts & Telecommun State Key Lab Informat Photon & Opt Commun Beijing 100876 Peoples R China

constant modulus algorithm (CMA) is widely applied for polarization demultiplexing in coherent optical communication system. However, the singular value problem always plagues CMA. Modified CMA based on polarization demultiplexing in Stokes space (SS-PDM) was proposed to avoid the singular value problem in simulation. Here we firstly experimentally demonstrate the modified CMA based on SS-PDM in optical coherent receivers. We conduct experiment of 40-Gbit/s polarization multiplexing (PDM) QPSK to verify this method. The experimental results show that the singularity problem of CMA disappears for Polarization-dependent loss (PDL) of 2.7 dB and 4.8 dB by using the modified CMA and the convergence speed of the modified CMA increases significantly compared with that of conventional CMA.

关键词： Polarization demultiplexing Coherent detection constant modulus algorithm Stokes space Polarization-dependent loss

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constant modulus algorithm for blind equalization of multipath transmitted video signals in cable networks

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2001年第5期16卷 413-420页

作者： Lei, ZC Franzen, O Brakensiek, J Schröder, H Univ Dortmund Chair Commun Tech D-44227 Dortmund Germany

In this paper we present an approach to equalize multipath transmitted video signals without any reference signal. This approach takes advantage of the constant envelope feature of the color burst signal, which is transmitted in the blanking interval of each TV line and can be considered as an angle-modulated signal. The constant modulus algorithm (CMA) after Treichler is modified for our purpose. Special attention is given to the equalization of video signals in PAL systems. By making full use of the genuine phase feature of the color burst signal in PAL systems, the Hilbert transform needed by CMA can be saved for equalizing PAL system video signals. In addition to equalize analog TV signal, this paper can also lead to a joint echo cancellation of analog and digital TV signals transmitted in cable network. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： constant modulus algorithm CMA blind equalisation video equalising color burst cable network equalisation echo cancellation

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constant modulus algorithm aided soft decision directed scheme for blind space-time equalisation of SIMO channels

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SIGNAL PROCESSING 2007年第11期87卷 2587-2599页

作者： Chen, S. Wolfgang, A. Hanzo, L. Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England

This paper investigates a blind space-time equaliser (STE) designed for single-input multiple-output (SIMO) systems that employ high-throughput quadrature amplitude modulation schemes. A constant modulus algorithm (CMA) aided soft decision-directed (SDD) scheme, originally derived for low-complexity blind equalisation of single-input single-output channels, is extended to the SIMO scenario. Simulations are conducted to compare the performance of this blind adaptive scheme with another low-complexity blind STE referred to as the CMA aided decision directed (DD) scheme. The results obtained demonstrate that for SIMO systems the CMA aided SDD scheme exhibits advantages over the CMA aided DD arragement, in terms of its faster convergence speed and lower computational complexity.(c) 2007 Elsevier B.V. All rights reserved.

关键词： single-input multiple-output space-time equalisation quadrature amplitude modulation constant modulus algorithm decision-directed adaptation

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Widely linear UKF constant modulus algorithm for blind adaptive beamforming

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Journal of Systems Engineering and Electronics 2017年第3期28卷 413-423页

作者： Huaming Qian Ke Liu Long Li Linchen Qian Junda Ma College of Automation Harbin Engineering University Advanced Signal Processing Lab College of EngineeringTemple University Information Communication Branch State Grid Heilongjiang Electric Power Company Limited School of Computing Beihang University

Based on a uniform linear array, a new widely linear unscented Kalman filter-based constant modulus algorithm (WL-UKF-CMA) for blind adaptive beamforming is proposed. The new algorithm is designed according to the constant modulus criterion and takes full advantage of the noncircular property of the signal of interest (SOI), significantly increasing the output signal-to interference-plus-noise ratio (SINR), enhancing the convergence speed and decreasing the steady-state misadjustment. Since it requires no known training data, the proposed algorithm saves a large amount of the available spectrum. Theoretical analysis and simulation results are presented to demonstrate its superiority over the conventional linear least mean square-based CMA (L-LMS-CMA), the conventional linear recursive least square-based CMA (L-RLS-CMA), WL-LMS-CMA, WL-RLS-CMA and L-UKF-CMA.

关键词： widely linear filtering blind beamforming noncircular signals constant modulus algorithm unscented Kalman filtering

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Fractionally spaced blind equalization with low-complexity concurrent constant modulus algorithm and soft decisiondirected scheme

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INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING 2005年第6期19卷 471-484页

作者： Chen, S Chng, ES Univ Southampton Sch Elect & Comp Sci Southampton SO17 1BJ Hants England Nanyang Technol Univ Sch Comp Engn Singapore 639798 Singapore

The paper proposes a low-complexity concurrent constant modulus algorithm (CMA) and soft decision-directed (SDD) scheme for fractionally spaced blind equalization of high-order quadrature amplitude modulation channels. We compare our proposed blind equalizer with the recently introduced state-of-art concurrent CMA and decision-directed (DD) scheme. The proposed CMA + SDD blind equalizer is shown to have simpler computational complexity per weight update, faster convergence speed, and slightly improved steady-state equalization performance, compared with the existing CMA + DD blind equalizer. Copyright (c) 2004 John Wiley & Sons, Ltd.

关键词： fractionally spaced blind equalization quadrature amplitude modulation constant modulus algorithm decision-directed adaptation

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Performance analysis of the linearly constrained constant-modulus algorithm-based multiuser detector

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2005年第2期53卷 643-653页

作者： Whitehead, JB Takawira, F Univ KwaZulu Natal Sch Elect Elect & Comp Engn ZA-4001 Durban South Africa

This paper quantifies the adaptive performance of a blind adaptive multiuser detector (MUD) based on the linearly constrained constant modulus algorithm (LCCMA) in both a stationary and nonstationary channel. A framework is developed to apply the feedback analysis method to analyzing adaptive MUD schemes. A closed-form expression for the excess mean square error (EMSE) of LCCMA blind adaptive MUD in a CDMA communications system is derived for both of the steady-state and tracking cases. The effects of additive noise and multiple access interference are considered. A transient analysis is performed that predicts the learning curve of the adaptive filter. Computer simulation is used to verify the accuracy of the analysis.

关键词： blind adaptive multiuser detection code division multiple access constant modulus algorithm excess mean square error feedback analysis steady-state analysis tracking analysis

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Modified constant modulus algorithm With Polarization Demultiplexing in Stokes Space in Optical Coherent Receiver

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2013年第19期31卷 3203-3209页

作者： Yu, Zhenming Yi, Xingwen Zhang, Jing Deng, Mingliang Zhang, Hongbo Qiu, Kun Univ Elect Sci & Technol China Key Lab Opt Fiber Sensing & Commun Minist Educ Chengdu 611731 Peoples R China

We propose a modified method of constant modulus algorithm (CMA) based on polarization demultiplexing in Stokes space for polarization demultiplexing (SS-PDM) in optical coherent receivers. SS-PDM can tolerate chromatic dispersion (CD) and polarization-dependent loss (PDL), but is sensitive to PMD. On the other hand, the CMA with high-order FIR filters could compensate for polarization-mode-dispersion (PMD) effectively, but suffers from the singularity problem which results from PDL. Therefore, we use the polarization rotation matrix estimated by SS-PDM to set the initial center taps of the CMA. The singularity problem of the CMA is avoided effectively in a much wider range of PDL and its convergence speed is also improved. We demonstrate this modified CMA in a simulation of 100-Gbit/s PDM-QPSK with PDL of 1, 3, and 5 dB, respectively. PDL is emulated by attenuating one polarization tributary before polarization multiplexing and the interaction between PDL and PMD is ignored. The singularity problem disappears as expected. Because the tolerance of PDL is affected by DGD, we further investigate the PDL tolerance under different DGD. Finally, we conduct the simulation of 100-Gbit/s PDM-QPSK with PDL of 3 dB over 3000 km SSMF and 4000 km SSMF separately. The convergence speed accelerates indeed compared with that of the conventional CMA.

关键词： Coherent detection constant modulus algorithm polarization demultiplexing polarization-dependent loss polarization-mode-dispersion Stokes space

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Anchored blind equalization using the constant modulus algorithm

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 1997年第5期44卷 397-403页

作者： Kamel, RE BarNess, Y NEW JERSEY INST TECHNOL DEPT ELECT & COMP ENGN CTR COMMUN & SIGNAL PROCESS RES NEWARK NJ 07102 USA

Blind equalization is a technique of adapting an equalizer without the need of a training sequence, The constant modulus algorithm (CMA) is one of the first known blind equalization algorithms. The cost function of the CMA exhibits local minima, which are the primary cause of the ill-convergence of the CMA, Using the CMA with an anchored equalizer greatly improves the performance of the CMA in terms of ill-convergence. This technique is used in this paper with the linear and the decision feedback equalizers, Theory and simulation show that such an adaptive equalizer will always remove intersymbol interference (ISI) provided the main cursor's gain exceeds a certain critical value.

关键词： blind equalization constant modulus algorithm

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Electromagnetism-like method tuned constant modulus algorithm for blind detector in multicarrier CDMA system

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2014年第2期27卷 233-247页

作者： Hung, Ho-Lung Chien Kuo Technol Univ Dept Elect Engn Changhua 500 Taiwan

This paper presents an efficient meta-heuristic algorithm based on electromagnetism-like method, which has been successfully implemented in multiuser detection problems. The contribution revisits blind multiuser detection for multicarrier code division multiple access systems using a novel combined adaptive step-size constant modulus algorithm (CMA) and electromagnetism-like method scheme. To work around potentially computational intractability and improved the capability of suppressing multiple access interference (MAI) for Multicarrier CDMA System, the proposed scheme exploits heuristics in consideration of both global and local exploration of the step size of the CMA. Simulation results obtained confirm that faster convergence and desirable BER performance with low computational complexity can be achieved with electromagnetism-like method based CMA scheme, compared with the previous step-size CMA scheme, genetic algorithm, and particle swarm optimization with CMA scheme. Copyright (c) 2012 John Wiley & Sons, Ltd.

关键词： constant modulus algorithm blind multiuser detection electromagnetism-like method artificial intelligence scheme multi-carrier code division multiple access

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Blind channel estimation for Multiple-Input Multiple-Output system using constant modulus algorithm

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COMPUTERS & ELECTRICAL ENGINEERING 2015年 44卷 42-50页

作者： Kanmani, M. Kannan, M. Anna Univ Dept ECE Jerusalem Coll Engn Madras 600025 Tamil Nadu India Anna Univ Dept Elect Engn Madras Inst Technol Madras 600025 Tamil Nadu India

Multiple-Input Multiple-Output system plays a major role in the fourth generation wireless systems to provide high data rates. In this paper, a blind channel estimation approach has been proposed for finding the channel length based on the signals received from the MIMO (Multiple-Input Multiple-Output) transceiver. The resultant MIMO channel length information is utilized for estimation of the channel impulse response of the system. The estimation is used for adaptation of the equalizer weights, based on the proposed constant modulus algorithm which has reduced the fading and multipath propagation resulting from Inter Symbol Interference. The performance of the proposed system has been analyzed in terms of Mean Square Error and Symbol Error Rate for various Signal to Noise Ratio. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Multiple-Input Multiple-Output Channel length estimation constant modulus algorithm Blind equalization Inter Symbol Interference

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