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Characteristics of filtering effect for a polarization division multiplexed-quadrature phase shift keying signal with Nyquist and super-Nyquist spectrum efficiency employing various algorithms

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OPTICAL ENGINEERING 2014年第7期53卷 1-5页

作者： Shi, Jianyang Zhang, Junwen Tao, Li Wang, Yiguang Wang, Yuanquan Chi, Nan Fudan Univ Dept Commun Sci & Engn Shanghai 200433 Peoples R China Fudan Univ Key Lab Informat Sci Electromagnet Waves MoE Shanghai 200433 Peoples R China

Quadrature duobinary (QDB) spectrumshaping polarization division multiplexed-quadrature phase shift keying (PDM-QPSK) signal with Nyquist and super-Nyquist spectrum efficiency will be a promising candidate for future ultrahigh speed ultrahigh spectrum efficiency coherent optical fiber transmissions systems. Several equalization algorithms including constant modulus algorithm (CMA), CMA plus postfilter, and cascaded multimodulus algorithm (CMMA) have been proposed as effective solutions for QDB-PDM-QPSK signal. For the first time as far as we know, the application conditions and performances for these three algorithms are analyzed and compared. System performances for a 112-Gb/s QDB-PDM-QPSK signal as a function of the optical filtering bandwidth and the optical SNR have been theoretically investigated. The results show that CMA would be the best choice in terms of convergence rate for general filtering. However, CMMA can outperform the other two schemes with a good receiver sensitivity and high-dynamic range of optical signal to noise ratio giving a strong filtering effect of super-Nyquist signaling. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： Nyquist constant modulus algorithm postfilter cascaded multimodulus algorithm

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Space-time interference suppression in DS/CDMA networks

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ELECTRONICS LETTERS 1999年第7期35卷 544-545页

作者： Xu, B Vu, TB Univ New S Wales Sch Elect Engn Sydney NSW 2052 Australia

Low-complexity adaptive receivers based on smart antennas with post- and pre-despreading structures are presented. Comparisons between three space-time (ST) schemes employing minimum-mean-square-error, a constant modu... 详细信息

关键词： decision-directed algorithm Electromagnetic compatibility and interference smart antennas radio receivers Multiple access communication space-time adaptive processing RFI constant modulus signals interference suppression minimum-mean-square-error post-despreading structures radiofrequency interference space-time interference suppression low-complexity adaptive receivers Antenna arrays Radio links and equipment adaptive antenna arrays radio networks spread spectrum communication pre-despreading structures Signal processing and detection code division multiple access constant modulus algorithm DS-CDMA networks

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Blind CMA-based asynchronous multiuser detection using generalized sidelobe canceller with decision feedback

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IEICE TRANSACTIONS ON COMMUNICATIONS 2008年第1期E91B卷 376-380页

作者： Chang, Ann-Chen Jen, Chih-Wei Ling Tung Univ Dept Informat Technol Taichung 408 Taiwan Minist Natl Defense Taipei 100 Taiwan

This letter deals with blind multiuser detection based on the multi-channel linearly constrained constant modulus algorithm (MLCCMA) for asynchronous code division multiple access (CDMA) systems over frequency-selective Rayleigh fading channels. In conjunction with the decision-feedback generalized sidelobe canceller (DFGSC), we present an efficient approach to combat multiple access interference and intersymbol interference. Computer simulations confirm that the proposed MLCCMA-based DFGSC can significantly speed up convergence and improve the output performance.

关键词： CDMA asynchronous constant modulus algorithm decision-feedback generalized sidelobe canceller

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Set-Membership Adaptive constant modulus Beamforming Based on Generalized Sidelobe Cancellation with Dynamic Bounds

Set-Membership Adaptive Constant Modulus Beamforming Based o...

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ISWCS 2013;The Tenth International Symposium on Wireless Communication Systems

作者： Yunlong Cai Rodrigo C. de Lamare Zhejiang University University of York

In this work, we propose an adaptive setmembership constant modulus (SM-CM) algorithm with a generalized sidelobe canceler (GSC) structure for blind beamforming. We develop a stochastic gradient (SG) type algorithm based on the concept of SM filtering for adaptive implementation. The filter weights are updated only if the bounded constraint cannot be satisfied. In addition, we also propose an extension of two schemes of time-varying bounds for beamforming with a GSC structure and incorporate parameter and interference dependence to characterize the environment for improving the tracking performance of the proposed algorithm in dynamic scenarios. Simulation results show that the proposed adaptive SM-CM-GSC algorithm with dynamic bounds achieves superior performance to previously reported methods at a reduced update rate.

关键词： Adaptive beamforming Set-membership filtering constant modulus algorithm

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Image transmission through ionospheric channel

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ELECTRONICS LETTERS 2005年第2期41卷 80-82页

作者： Erhel, YM Perrine, C Lemur, D Bourdillon, A Ctr Rech Ecoles Coetquidan St Cyr F-56381 Guer France Univ Rennes 1 Inst Electron & Telecommun Rennes F-35042 Rennes France

An operational system for image transmission through the ionospheric channel is presented. For a range of 780 kin, the 'high' data transfer rate attains 30 kbits/s in a 9 kHz bandwidth with the implementation of a blind spatio-temporal equalisation based on the constant modulus algorithm. This value significantly exceeds the current standard for HF modems (4.8 kbits/s). The quality of the transmitted images appears to be good compared with the original.

关键词： active antenna arrays blind equalisers loop antennas radio links spatiotemporal phenomena telecommunication channels visual communication 30 kbit/s 780 km 9kHz active antenna arrays blind spatiotemporal equalisation constant modulus algorithm high data

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Adaptive Blind Equalization for MIMO Systems under α-Stable Noise Environment

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IEEE COMMUNICATIONS LETTERS 2009年第8期13卷 609-611页

作者： Li Sen Qiu Tianshuang Zha Daifeng Dalian Univ Technol Coll Elect & Informat Engn Dalian Peoples R China Dalian Maritime Univ Informat Sci Technol Coll Dalian Peoples R China

The presence of non-Gaussian impulsive noise in wireless system can degrade the performance of existing equalizers and signal detectors. In this paper, the problem of blind source separation and equalization for MINI systems in heavy-tailed impulsive noise is studied. A generalized multi-user constant modulus cost function by employing the fractional lower-order statistic of the equalizer input signal is proposed. The associated adaptive blind equalization algorithm based on a stochastic gradient descent method is defined as fractional lower-order multi-user constant modulus algorithm (FLOS_MU_CMA). Computer simulations are presented to illustrate the performance of the new algorithm

关键词： alpha-stable distribution constant modulus algorithm fractional lower-order statistics MIMO equalization

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Blind Equalization Method Based on Sparse Bayesian Learning

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IEEE SIGNAL PROCESSING LETTERS 2009年第4期16卷 315-318页

作者： Hwang, Kyuho Choi, Sooyong Yonsei Univ Sch Elect & Elect Engn Seoul 120749 South Korea

A novel adaptive blind equalization method based on sparse Bayesian learning (blind relevance vector machine (RVM) equalizer) is proposed. This letter incorporates a Godard or constant modulus algorithm (CMA)-like error function into a general Bayesian framework. This Bayesian framework can obtain sparse solutions to regression tasks utilizing models linear in the parameters. By exploiting a probabilistic Bayesian learning framework, the sparse Bayesian learning provides the accurate model for the blind equalization, which typically utilizes fewer basis functions than the equalizer based on the popular and state-of-the-art support vector machine (SVM) -blind SVM equalizer. Simulation results show that the proposed blind RVM equalizer provides improved performances in terms of complexity, stability and intersymbol interference (ISI) and bit error rate (BER) in a linear channel and a similar BER performance in a nonlinear channel compared to the blind SVM equalizer.

关键词： Blind equalization constant modulus algorithm relevance vector machine

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Adaptive Minimum Entropy Equalization algorithm

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IEEE COMMUNICATIONS LETTERS 2010年第10期14卷 966-968页

作者： Abrar, Shafayat Nandi, Asoke K. Dept Elect Engn & Elect Liverpool L69 3GJ Merseyside England

We employ minimum entropy deconvolution principle for blind equalization of complex digital signals. In essence, we maximize the output energy, constrain the equalizer output not to exceed certain level and obtain an adaptive solution capable of opening a closed-eye with the recovery of true energy of signal. We provide evidence of good performance in comparison to existing adaptive methods, like CMA and its variants, through simulations.

关键词： Adaptive equalizers blind equalization minimum entropy deconvolution constant modulus algorithm

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Newton-like minimum entropy equalization algorithm for APSK systems

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SIGNAL PROCESSING 2014年 101卷 74-86页

作者： Ali, Anum Abrar, Shafayat Zerguine, Azzedine Nandi, Asoke K. King Fahd Univ Petr & Minerals Dhahran 31261 Saudi Arabia COMSATS Inst Informat Technol Islamabad Pakistan Brunel Univ Uxbridge UB8 3PH Middx England

In this paper, we design and analyze a Newton-like blind equalization algorithm for the APSK system. Specifically, we exploit the principle of minimum entropy deconvolution and derive a blind equalization cost function for APSK signals and optimize it using Newton's method. We study and evaluate the steady-state excess mean square error performance of the proposed algorithm using the concept of energy conservation. Numerical results depict a significant performance enhancement for the proposed scheme over well established blind equalization algorithms. Further, the analytical excess mean square error of the proposed algorithm is verified with computer simulations and is found to be in good conformation. (C) 2014 Elsevier B.V. All rights reserved.

关键词： constant modulus algorithm Blind equalizer Recursive least squares algorithm Newton's method Tracking performance Amplitude phase shift keying

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Quantized CMA equalization for shaped signal constellations

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IEEE SIGNAL PROCESSING LETTERS 2004年第2期11卷 67-70页

作者： Athuraliya, SA Garth, LM Univ Canterbury Dept Elect & Comp Engn Christchurch 1 New Zealand

Constellation shaping introduced to maximize channel capacity is detrimental to the performance of many cost function-based blind equalization algorithms including the constant modulus algorithm (CMA). We propose a new multi-modulus algorithm closely related to CMA, but robust against changes in the statistical nature of the signal due to constellation shaping. While CMA behaves properly only for sub-Gaussian distributions, the algorithm we develop is applicable to a broad class of distributions including Gaussian and super-Gaussian.

关键词： blind equalization constant modulus algorithm shaped constellation shell mapping

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