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Zhiyuan Wu Xiaofeng Wang 《Communications Letters, IEEE》2006,10(8):582-584
In this letter, a new multi-user detection scheme is proposed. It employs a novel nonlinear minimum mean square error (MMSE) estimator that exploits the knowledge of symbol alphabet to estimate the interfering signals. After cancelling the estimated interference, a conventional linear multi-user detector such as the MMSE detector or, simply, the matched-filter receiver (MFR) is then used to detect the desired user signal. Simulation results demonstrate that the proposed detector significantly outperforms the conventional linear MMSE detector. 相似文献
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针对STBC-OFDM系统,分析了STBC-OFDM系统的MMSE检测算法和ML检测算法。考虑到最大似然多用户检测算法实现的复杂性,研究了将MMSE检测算法和ML-PDP检测算法相结合进行多用户联合检测,对其进行了仿真,仿真结果表明MMSE-ML联合检测算法与MMSE检测算法相比,计算量有所增加,但可以较大程度地提高检测系统的误码性能。 相似文献
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CDMA作为第三代无线通信系统,具有频谱利用率高、保密性强、可多址复用等优点。在移动通信领域,越来越受到人们的普遍关注和重视。文章阐述了多址干扰产生的原因及其对系统性能的影响。通过MATLAB/Simulink建立仿真平台,设计并实现了直接序列扩频通信中信号的收发,采用误码率这一指标,重点对比分析传统单用户检测器、解相关线性检测器和最小均方误差检测器对系统性能的影响。实验结果表明,解相关线性多用户检测器在抑制多址干扰方面占有明显的优势。 相似文献
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实际在CDMA系统中,多址干扰(MAI)是主要的干扰来源,多用户检测技术完全可以抑制这种多址干扰。论文分析了几种典型的多用户检测技术,并在高斯信道环境下对解相关检测器、最小均方误差检测器和传统检测器进行了仿真和性能比较。 相似文献
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Sacchi C. Donelli M. D'Orazio L. Fedrizzi R. De Natale F.G.B. 《Electronics letters》2007,43(3):172-173
A novel multi-user detector, based on a genetic algorithm-assisted per-carrier MMSE criterion, is proposed for MC-CDMA systems transmitting over time-varying multipath fading channels. The analysed multi-user detector outperforms state-of-the-art adaptive receivers based on deterministic gradient algorithms, particularly for an increasing number of users 相似文献
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Blind multi-user detection is of special interest for multiple access interference (MAI) mitigation in code-division multiple-access (CDMA) systems since it is impractical to assume perfect knowledge of parameters such as spreading codes, time delays and amplitudes of all the users in a rapidly changing mobile environment. In [1], the blind decorrelating detector and the minimum mean square error (MMSE) detector were developed based on subspace estimation and derived in closed forms of the signal subspace components. To combat frequency-selective fading, the subspace approach to blind multi-user detection was extended to multi-carrier CDMA (MCCDMA) systems, e.g. in [2]. In this Letter, we develop further the algorithm presented in [1, 2], and show how the condition of the signal subspace can be improved by using not only the autocorrelation, but also the pseudo-autocorrelation of the received observations, leading to improved performance in blind multi-user detection. 相似文献
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This letter proposes a novel hybrid turbo multi-user (MU) detection technique based on group-wise soft interference canceling minimum mean-square error filtering (SC-MMSE) combined with maximum a posteriori (MAP) signal detection for OFDM MU systems. A new user grouping algorithm is developed that exploits the knowledge of the pairwise spatial correlation among the channels of each group, of which aim is to reduce noise enhancement due to the MMSE interference suppression of highly correlated user signals. It is shown that the proposed detector can achieve significant performance improvements over SC-MMSE in the presence of high spatial channel correlation 相似文献
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多用户检测技术是第三代移动通信系统CDMA中的一项关键技术。在多用户检测中求解最佳矢量问题可以转化为在遗传算法中求解具有最高适应度函数的问题。本文提出了一种基于并行遗传算法的CDMA多用户检测器,并与最佳多用户检测和传统检测器进行比较,实验结果表明本方法可获得接近最佳检测的性能。由于采用并行遗传算法,这种多用户检测器更易于实时应用和硬件实现。 相似文献
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By combining multipath processing, differential signal detection, and multiuser detection techniques, we develop a class of near-far resistant linear detectors for differentially coherent multipath signals. We derive and establish performance relationships among the following detectors: an optimally near-far resistant detector, a suboptimum detector which does not require knowledge of the signal coordinates, and a minimum mean square error (MMSE) detector which achieves near-optimum asymptotic efficiency. We present an adaptive multiuser detector which converges to the MMSE detector without training sequences and which requires less information than the conventional single user rake receiver. 相似文献
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The polynomial expansion (PE) multi-user detector was proposed to eliminate the computational complexity of matrix inversion involved in the decorrelating detector and the MMSE detector. Computation of the polynomial coefficients in a PE detector is, however, a complex task. A fast converging adaptive algorithm based on the Davidon-Fletcher-Powell (DFP) method is proposed for computing polynomial weights for a PE detector 相似文献
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This paper proposes QR-based criteria for efficient selection of multi-mode precoders in multi-user multiple-input multiple-output (MU-MIMO) precoded systems with a limited feedback. In particular, a MU-MIMO QR based precoding scheme is developed which takes advantage of the overall precoder design among users in conjunction with QR detection. A selection criterion is developed to identify the precoder that yields the maximum free distance. Efficient mode selection and tree search strategies are adopted to reduce the complexity associated with the identification of the optimum precoder. To further improve the detection performance in correlated channels, an efficient QR-based MMSE V-BLAST detector is proposed. Computer simulations confirm that the proposed QR-based precoding scheme attains the performance of existing schemes with a significantly lower complexity level. 相似文献
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The combination of antenna array beamforming with multiuser detection can effectively improve the detection efficiency of a wireless system under multipath interference, especially in a fast‐fading channel. This paper studies the performance of an adaptive beamformer incorporated with a block‐wise minimum mean square error(B‐MMSE) detector, which works on a unique signal frame characterized by training sequence preamble and data blocks segmented by zero‐bits. Both beam‐former weights updating and B‐MMSE detection are carried out by either least mean square (LMS) or recursive least square (RLS) algorithm. The comparison of the two adaptive algorithms applied to both beamformer and B‐MMSE detector will be made in terms of convergence behaviour and estimation mean square error. Various multipath patterns are considered to test the receiver's responding rapidity to changing multipath interference. The performance of the adaptive B‐MMSE detector is also compared with that of non‐adaptive version (i.e. through direct matrix inversion). The final performance in error probability simulation reveals that the RLS/B‐MMSE scheme outperforms non‐adaptive B‐MMSE by 1–5 dB, depending on the multipath channel delay profiles of concern. The obtained results also suggest that adaptive beamformer should use RLS algorithm for its fast and robust convergence property; while the B‐MMSE filter can choose either LMS or RLS algorithm depending on antenna array size, multipath severity and implementation complexity. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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针对码分多址接入(CDMA)系统中最优多用户检测的指数计算复杂度问题,结合CDMA通信的实际特点,利用进化规划免去了交叉操作因而计算复杂度小的特点,提出了一种基于进化规划的多用户检测问题的优化处理方法。实验结果表明本方法可获得接近最佳检测的性能,但计算复杂度降低。 相似文献
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Teng Joon Lim Rasmussen L.K. Sugimoto H. 《Selected Areas in Communications, IEEE Journal on》1998,16(9):1711-1722
We introduce a multiuser receiver based on the Kalman filter, which can be used for joint symbol detection and channel estimation. The proposed algorithm has the advantage of working even when the spreading codes used have a period larger than one symbol interval (“long codes”), unlike adaptive equalizer-type detectors. Simulation results which demonstrate the performance advantage of the proposed receiver over the conventional detector, the minimum mean squared error (MMSE) detector and a recursive least squares (RLS) multiuser detector are presented. A thorough comparison of the MMSE detector and the proposed detector is attempted because the Kalman filter also solves the MMSE parameter estimation problem, and it is concluded that, because the state space model assumed by the Kalman filter fits the code division multiple access (CDMA) system exactly, a multiuser detector based on the Kalman filter must necessarily perform better than a nonrecursive, finite-length MMSE detector. The computational complexity of the detector and its use in channel estimation are also studied 相似文献
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《中国邮电高校学报(英文版)》1999,(1)
lintroductionCDMA,owingtoitshighcapacitypotentialandotherdesirablefeatures,suchasanti-mutipath,fadingandantljammingcapabilities,isaimatprovidingamuchhighercapacitythanthepreviousgenerationsofmobilecommunicationsystems.ThistechniquepermitSalltheuserin... 相似文献
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该文给出了一种基于负熵准则的FastICA盲多用户检测方法。修改了FastICA算法中的非2次函数,引入4次幂函数,把基于负熵的非高斯性测度转化为信号峰度的形式,这样降低了计算量。同时,算法充分考虑了各个用户信号的统计独立性,在下行链路干扰用户的扩频码未知情况下,把目标用户的扩频码作为训练序列,并用于初始化FastICA算法的分离向量,使用随机梯度法进行优化计算,能够获得优异的符号估计性能。对算法的计算复杂度的分析可以看出,计算量随着接收数据长度和用户数的增加而增加。通过与传统匹配滤波器,MMSE检测算法比较,表明在同步CDMA信道中,MAI较低时算法检测性能与MMSE检测器的性能接近,随着MAI增加,算法的性能明显优于MMSE算法。 相似文献