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An orthogonalized blind algorithm for hybrid of adaptive array and equalizer

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2014年第2期27卷 201-215页

作者： Leou, Maw-Lin Wu, Chien-Min Liaw, Yi-Ching Su, Hui-Kai NanHua Univ Dept Comp Sci & Informat Engn Chiayi 622 Taiwan Natl Formosa Univ Dept Elect Engn Huwei 632 Yunlin Taiwan

The problems generated by the interference will be more complicated in the future. A combination of adaptive array and equalizer has been employed to solve the problems of interference when an adaptive array alone cannot suppress all the interferences. A constant modules algorithm (CMA) of the combination system was proposed to solve the problems of insufficient degrees of freedom and main-beam multipath interference when no training signal is transmitted. The limitation of the CMA for combination systems is due to its slow rate of convergence. In this paper, an orthogonalized blind algorithm for hybrid of array and equalizer (OBHAE) is proposed to combat the problems of the interference. Because the modified input vector of the adaptive array is orthogonalized by the OBHAE in advance, the convergent rate of the CMA system can be improved by the OBHAE. When the coherent interference presents, the performance of the system will be degraded. In this paper, an orthogonalized spatial smoothing blind (OSSB) algorithm is proposed to further enhance the cancellation of the coherent interference. In the OSSB, we combine the OBHAE with the spatial smoothing method to combat the coherent interference problem. Simulation results are presented to demonstrate the merits of the OBHAE and the OSSB. Copyright (c) 2012 John Wiley & Sons, Ltd.

关键词： adaptive array equalizer constant modulus algorithm degrees of freedom main-beam multipath interference orthogonalized blind algorithm

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Space-Time Semi-Blind Equalizer for Dispersive QAM MIMO System Based on Modified Newton Method

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2014年第6期13卷 3244-3256页

作者： Li, Jin Feng, Da-Zheng Zheng, Wei Xing Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Peoples R China Univ Western Sydney Sch Comp Engn & Math Penrith NSW 2751 Australia

This paper proposes a space-time semi-blind equalizer (ST-SBE) for dispersive multiple-input multiple-output (MIMO) communication systems that employ high throughput quadrature amplitude modulation (QAM) signals. A novel cost function (CF) that integrates multimodulus algorithm (MMA) with soft decision-directed (SDD) scheme is established to efficiently obtain the weight vector associated with the ST-SBE. In the ST-SBE, a very short training sequence is used to provide a rough initial least squares estimate of the weight vector. An efficient modified Newton method (MNM) for minimizing the established cost function is proposed to fast search the optimal weight vector. Very interestingly, we prove that the proposed MNM has the same quadratic order of convergence as Newton methods. In addition, the proposed MNM has much lower computational complexity than Newton methods. Simulation results are provided to demonstrate that the ST-SBE has better performances than the gradient-Newton (GN)-based concurrent constant modulus algorithm (CMA) with SDD scheme (GN-CMA+SDD).

关键词： Space-time semi-blind equalizer modified Newton method constant modulus algorithm multimodulus algorithm soft decision-directed scheme

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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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Series Equalizer Based on constant modulus algorithm and Decision-directed algorithm

Series Equalizer Based on Constant Modulus Algorithm and Dec...

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Asia-Pacific Conference on Information Processing (APCIP 2009)

作者： Rao, Wei Liu, Jian-bing Liu, Yuan-yuan Tan, Wen-qun Xu, Hui-jun Yuan, Kang-ming Dai, Guo-xing Nanchang Inst Technol Nanchang 330099 Peoples R China

ISBN: (纸本)9780769536996

A new series equalizer based on constant modulus algorithm (CMA) and Decision-directed (DD) algorithm is proposed to overcome Inter-Symbol Interference (ISI) much better in the communication system without the aid of training sequences. The proposed equalizer uses the CMA as the forward filter and DD algorithm as the back filter. These two filters are series and operate concurrently. It makes full use of the advantages of the CMA's "eye-opened" ability and DD's superior convergence performance. Therefore the proposed equalizer obtains not only the faster convergence and lower residual error but also the ability of phase rotation-compensated. Computer simulations with underwater acoustic channels are presented and the simulation results are shown to prove the efficiency of the proposed equalizer.

关键词： seriers equalizer constant modulus algorithm decision-directed algorithm underwater acoustic channel

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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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CMA-Based CD and DGD Estimation in Presence of Experimental Higher Order PMD

CMA-Based CD and DGD Estimation in Presence of Experimental ...

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European Conference on Optical Communication (ECOC)

作者： Zakrisson, Daniel Karlsson, Magnus Johannisson, Pontus Chalmers Photon Lab Dept Microtechnol & Nanosci SE-41296 Gothenburg Sweden

We evaluate 3 methods for CD estimation using CMA filter tap coefficients. The performance of these methods are evaluated with respect to their accuracy and range. We also experimentally evaluate the CD estimation per... 详细信息

ISBN: (纸本)9781479930661

关键词： FIR filters adaptive equalisers delay estimation optical communication optical dispersion optical information processing CD estimation performance CMA FIR filter tap coefficients CMA-based CD DGD estimation adaptive equalizer chromatic dispersion constant modulus algorithm differential group delay estimation experimental higher order PMD polarization mode dispersion Dispersion Estimation Filter banks Filtering theory Finite impulse response filters Monitoring Receivers FIR filters Polarization mode dispersion adaptive equalisers filtering theory constant modulus algorithm (CMA) Optical computing Optical dispersion delay estimation Filter banks Chromatic dispersion Optical communication Receivers PLP1 wt Allele

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Blind Adaptive Polarization Demultiplexing in Coherent PDM QAM Systems 12

Blind Adaptive Polarization Demultiplexing in Coherent PDM Q...

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12th International Conference on Frontiers of Information Technology (FIT)

作者： Abrar, Shafayat Zerguine, Azzedine Nandi, Asoke K. COMSATS Inst Informat Technol Dept Elect Engn Islamabad 44000 Pakistan King Fahd Univ Petr & Minerals Dept Elect Engn Dhahran 31261 Saudi Arabia Brunel Univ Dept Elect & Comp Engn Uxbridge UB8 3PH Middx England

ISBN: (纸本)9781479975051

Polarization-division multiplexing (PDM) has emerged as a promising technique for increasing data rates without increasing symbol rates. However, the distortion effects of the fiber transmission medium poses severe barriers for the implementation of this technological alternative. Especially, due to the fiber-induced polarization fluctuation orthogonally transmitted PDM signals are mixed at the receiver input. Therefore, a receiver compensation structure needs to be implemented to recover the original orthogonal transmitted components from their mixtures at the end of the fiber channel. This is in fact the focus of this article where a receiver algorithm is based on a recently proposed minimum entropy equalization scheme exploiting the maximization of (an enhanced) energy cost function subject to the magnitude boundedness of (incoming) digital communication signals. Through the use of this scheme, new receiver algorithms for recovering the original polarization signals in an adaptive manner are proposed. The key feature of these algorithms is that they can achieve high equalization performance while maintaining the algorithmic complexity in a fairly low level that is suitable for implementation in optical fiber communication receivers. The performance of these algorithms for a square-QAM based coherent polarization division multiplexed system are illustrated through some simulation examples.

关键词： Adaptive filter constant modulus algorithm multimodulus algorithm polarization mode demultiplexing

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A Novel Blind Multi-Target Beam-Forming algorithm in Guidance Data Link System

A Novel Blind Multi-Target Beam-Forming Algorithm in Guidanc...

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26th Chinese Control and Decision Conference (CCDC)

作者： Wei Xufang Wu Cuisheng Yao Changhong Luoyang Optoelect Technol Dev Ctr Luoyang 471009 Peoples R China

ISBN: (纸本)9781479937066

This paper proposes a novel blind multi-target beam-forming algorithm to perform a multi-target beam-former for guidance data link system. The proposed algorithm exploits the knowledge of the pseudo-noise (PN) code used in data-link communication system to generate the transmitted command as reference signal. A novel approach, which a band-pass filter is used, is adopted to improve anti-jamming performance in environment with strong interference. Simulation results demonstrate that our proposal can achieve a superior anti-jamming performance than Multi-target Least Square constant modulus algorithm(MT-LSCMA) in environment with strong jamming.

关键词： Blind Multi-target Beam-forming constant modulus algorithm Guidance Data Link System

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Tracking Performance of Two constant modulus Equalizers

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IEEE COMMUNICATIONS LETTERS 2013年第5期17卷 830-833页

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

Exploiting the error variance relation, this letter discusses the evaluation of excess mean square error (EMSE) of constant modulus equalizers in a noise-free non-stationary environment. The EMSE analyses are presented for two equalizers - the CMA22 and the beta CMA. Simulation results show a close match in theoretical and simulated errors for both algorithms.

关键词： constant modulus algorithm blind equalization adaptive filter mean-square error steady-state analysis

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Blind equalization for minimum-shift keying coherent optical communication system

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OPTICAL ENGINEERING 2014年第4期53卷 046107-046107页

作者： Wang, Huanjun He, Jing Chen, Lin Tang, Jin Hunan Univ Coll Informat Sci & Engn Key Lab Micro Nano Optoelect Devices Minist Educ Changsha 410082 Hunan Peoples R China

The blind equalization of minimum-shift keying (MSK) in coherent optical communication is investigated. After the classical constant modulus algorithm (CMA) equalization step, the output of the equalizer does not necessarily coincide with a delayed and rotated version of the input MSK signal. In our MSK coherent optical system, a blind equalization criterion is proposed to eliminate the latter indeterminacy. Simulation results show that the 10-Gb/s MSK system successfully recovers MSK signal from various transmission impairments. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： blind equalization minimum-shift keying optical coherent system constant modulus algorithm

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