检索结果-内蒙古大学图书馆

IEEE Wireless Communications and Networking Conference

作者： Elnashar, A Elnoubi, S Elmikati, H Egyptian Co Mobile Serv MobiNil WTC Cairo Egypt

ISBN: (纸本)0780389662

A robust blind multiuser receiver based on a linearly constrained constant modulus algorithm (LCCMA) with multiple constraints and Quadratic Inequality (QI) constraint on the weight vector norm is developed in this paper. Quadratic constraints have been a prevalent approach to improve the robustness against mismatch and modeling errors, uncertainties in estimating the data autocovariance matrix, and random perturbations in detector parameters. In this paper, the LCCMA is realized using a fast steepest descent adaptive algorithm based on the partition linear interference canceller (PLIC) structure with multiple constraints and a QI constraint on the weight vector norm. The Lagrange multiplier methodology is exploited to solve the QI constraint problem. Simulations are carried out in a loaded multipath environment with near-far effect to validate the robustness of the proposed detector.

关键词： DS/CDMA multiuser detection constrained optimization quadratic inequality constraint constant modulus algorithm Lagrange method

来源：评论

学校读者我要写书评

暂无评论

Convergence Behavior of the constant modulus algorithm Controlled by Special Stepsize

Convergence Behavior of the Constant Modulus Algorithm Contr...

引用

2002年第6届信号处理国际会议

作者： Guo Li Li Ning Guo Yan Zhou Jiongpan (School of Information Engineering, BUPT, Beijing, 100876, China) (Institute of Science, PLAUST, Nanjing 210016, China)

The constant modulus algorithm (CMA) enjoys widespread popularity as methods for blind beamforming and equalization of communication signals. CMA is straightforward to implement, robust, and computationally of modest complexity. Despite its effectiveness and apparent simplicity, adaptive implementation of the CMA comes along with several complicating factors that have never really been solved. In particular, convergence can be unpredictable and slow depending on the stepsize. In this paper, Convergence behaviors of the constant modulus algorithm based on "1-2" cost function (CMA1-2) and "2-1" cost function (CMA2-1) are investigated. We found that certain signal could be quickly removed from the output data choosing special stepsize if at least two signals were with different power. Simulation examples confirm the results.

关键词： constant modulus algorithm stepsize singular value decomposition

来源：评论

学校读者我要写书评

暂无评论

Wordlength effect on CMA adaptive phased array antenna using fixed-point arithmetic

Wordlength effect on CMA adaptive phased array antenna using...

引用

Asia-Pacific Microwave Conference

作者： Boonpoonga, Akkarat Sirisuk, Phaophak Krairiksh, Monai Kings Mongkuts Inst Technol Ladkrabang Fac Engn Bangkok 10520 Thailand

ISBN: (纸本)078039433X

This paper investigates a wordlength effect on an adaptive phased array antenna using the constant modulus algorithm (CMA). The antenna is a flat four-beam compact phased array whose main beam can be switched into four directions by using four one-bit phase shifters. A beam with maximum received power is exploited as an initial beam for CMA. The wordlength investigation will be shown in term of the signal constellations, SINR trajectories and antenna patterns.

关键词： adaptive antenna arrays antenna radiation patterns fixed point arithmetic interference (signal) phase shifters 1 bit CMA adaptive phased array antenna SINR trajectories antenna patterns beam compact phased array constant modulus algorithm fixed-point ari antenna radiation patterns Fixed-point arithmetic constant modulus algorithm (CMA) adaptive antenna arrays Phase shifters interfering signal 1-bit CRANE MAINTENANCE AREA antenna phased arrays Antenna arrays

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Fast converging approach for blind constant modulus interference suppression

引用

JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS 2004年第2期27卷 275-279页

作者： Chang, AC Huang, ZF Natl Def Univ Chung Cheng Inst Technol Dept Elect Engn Taoyuan 335 Taiwan

The convergence behavior of the constant modulus algorithm (CMA) is examined in the proper initialization condition of locking onto the desired signal. An improved CMA converging approach is proposed that has the advantage of suppressing multiple access interference without explicit knowledge of interference parameters for synchronous DS-CDMA systems. Simulation results demonstrate that the method overcomes the slower convergence of the CMA in the sudden birth of the number of users and outperforms the CMA detector and matched filter.

关键词： CDMA constant modulus algorithm speed of convergence blind adaptive interference suppression

来源：评论

学校读者我要写书评

暂无评论

Pre-processing blind multiuser detection algorithm using antenna arrays

引用

Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology 2005年第10期27卷 1613-1615页

作者： Fu, Hong-Liang Feng, Guang-Zeng Nanjing University of the Posts and Telecommunications Nanjing 210003 China

A Pre-processing Decision-FeedBack Least Squares constant modulus blind multiuser detection algorithm (P-DFB-LSCMA) using antenna arrays is proposed in this paper. It pre-processes the received signals from the antenna arrays and utilizes the least squares constant modulus algorithm based on decision feedback to detection the DS-CDMA signals. Simulation results show that the proposed P-DFB-LSCMA algorithm is superior to DFB-LSCMA and LSCMA, especially with low SNR.

关键词： Antenna array Blind multiuser detect constant modulus algorithm Feedback P-DFB-LSCM

来源：评论

学校读者我要写书评

暂无评论

Low complexity constant modulus based cyclic blind adaptive multiuser detection

Low complexity constant modulus based cyclic blind adaptive ...

引用

7th Africon Conference in Africa

作者： Whitehead, J Takawira, F Univ KwaZulu Natal Sch Elect Elect & Comp Engn ZA-4041 Durban South Africa

ISBN: (纸本)0780386051

Periodically time varying (PTV) filters can offer significant performance gains over conventional filtering methods in DS-CDMA communications systems that are either multirate or corrupted by narrow band interference. This paper develops a new blind adaptive PTV linear multiuser detector based on the frequency shift (FRESH) architecture. The blind adaptive algorithm is based on the linearly constrained constant modulus algorithm (LCCMA), but is modified for the FRESH architecture. The resulting stochastic gradient algorithm has significantly less computational complexity than the recently proposed recursive and cyclic subspace tracking algorithms, and can offer comparable performance. The robustness of the FRESH-LCCMA algorithm is ensured through a proof of convergence which is carried out in the paper.

关键词： blind adaptive multiuser detection constant modulus algorithm cyclic algorithms DS-CDMA frequency shift filtering multi-rate CDMA

来源：评论

学校读者我要写书评

暂无评论

CMA-based channel estimation for space-time block coding transmission systems

引用

WIRELESS PERSONAL COMMUNICATIONS 2004年第4期28卷 241-258页

作者： Xu, CJ Le-Ngoc, T McGill Univ Dept ECE Montreal PQ H3A 2A7 Canada

In this paper, we present channel estimation methods for space-time block coding (STBC) transmissions using constant modulus algorithm (CMA). The channel estimates are directly calculated from the convergence value of the CMA. Two algorithms using the channel-vector-based and channel-gain-based constant modulus ( CM) criteria are proposed. An approximation of the CM cost function is introduced to allow the use of the recursive least-square (RLS) technique in designing fast RLS-CMA's. Performance of the proposed schemes is evaluated and compared with others using simulation. Illustrative results show that the proposed scheme outperforms the cross-correlated method and can approach the performance of the training-based method.

关键词： transmit diversity space-time block coding constant modulus algorithm channel estimation wireless communications

来源：评论

学校读者我要写书评

暂无评论

Blind channel estimation via combining autocorrelation and blind phase estimation

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS 2004年第6期51卷 1125-1131页

作者： Baykal, B Middle E Tech Univ Dept Elect & Elect Engn TR-06531 Ankara Turkey

Symbol spaced blind channel estimation methods are presented which can essentially use the results of any existing blind equalization method to provide a blind channel estimate of the channel. Blind equalizer's task is reduced to only phase equalization (or identification) as the channel autocorrelation is used to obtain the amplitude response of the channel. Hence, when coupled with simple algorithms such as the constant modulus algorithm (CMA) these methods at baud rate processing provide alternatives to blind channel estimation algorithms that use explicit higher order statistics (HOS) or second-order statistics (subspace) based fractionally-spaced/multichannel algorithms. The proposed methods use finite impulse response (FIR) filter linear receiver equalizer or matched filter receiver based infinite impulse response+FIR linear cascade equalizer configurations to obtain blind channel estimates. It is shown that the utilization of channel autocorrelation information together with blind phase identification of the CMA is very effective to obtain blind channel estimation. The idea of combining estimated channel autocorrelation with blind phase estimation can further be extended to improve the HOS based blind channel estimators in a way that the quality of estimates are improved.

关键词： blind channel estimation constant modulus algorithm higher order statistics matched filter receiver

来源：评论

学校读者我要写书评

暂无评论

A comparative study of two blind FIR equalizers

引用

DIGITAL SIGNAL PROCESSING 2004年第1期14卷 18-36页

作者： Chen, S Cook, TB Anderson, LC Univ Southampton Dept Elect & Comp Sci Southampton SO17 1BJ Hants England

The paper investigates blind tinite-impulse-response (FIR) equalization schemes for quadrature amplitude modulation signalling. We compare a bootstrap maximum a posteriori probability (MAP) equalizer witha recently introduced concurrent constant modulus algorithm (CMA) and decision directed (DD) equalizer (CMA+DD). Both equalizers are known to outperform the CMA considerably in the situations where carrier recovery is performed and the signal constellation is known. The concurrent CMA+DD equalizer has a complexity that is slightly more than twice of the CMA, and the bootstrap MAP equalizer has computational requirements that are only slightly more complex than the CMA. Simulation results indicate that the bootstrap MAP blind FIR equalizer has a faster convergence rate and better steady-state performance than the concurrent CMA+DD blind FIR equalizer, but tuning of the former is more complicated than the latter. (C) 2003 Elsevier Inc. All rights reserved.

关键词： blind equalization finite-impulse-response filter quadrature amplitude modulation constant modulus algorithm decision-directed adaptation maximum a posteriori probability

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：