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DS-CDMA通信系统中基于独立分量分析的盲多用户检测 总被引:3,自引:0,他引:3
本文研究了直接序列扩频码分多址(DS-CDMA)通信系统的多用户检测问题,提出了基于独立分量分析(ICA)方法的盲多用户检测算法,实现多用户信号的盲检测。该方法不需知道用户的扩频码就可完成多用户信号的盲检测。仿真结果验证了本文提出的方法的优良性能。 相似文献
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盲多用户检测技术是第三代移动通信的关键技术,本文仿真分析了DS-CDMA通信系统中盲多用户检测的Kalman滤波算法的性能.并且将子空间算法和Kalman滤波算法进行结合,使得盲多用户检测的Kalman滤波算法的计算量大大降低. 相似文献
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针对实际盲多用户检测系统中存在的大量噪声呈现非高斯性,而这种非高斯性使基于高斯噪声假定下的恒模盲多用户检测算法的性能显著退化甚至不能正常工作,本文提出了一种分数低阶统计量的广义恒模盲多用户检测算法.该算法是分数低阶统计量恒模算法的推广,能有效地应对非高斯噪声的影响,具有广泛的适用性.通过以DS-CMDA系统为例,将分数低阶统计量广义恒模肓多用户检测算法与传统恒模盲多用户检测算法(CMA)、分数低阶统计量恒模盲多用户检测算法(FLOS-CMA)进行了对比,实验仿真结果表明:无论在高斯白噪声下还是在α稳定分布噪声下,分数低阶统计量广义恒模盲多用户检测算法均具有良好的抗多址干扰和抑制噪声的性能,并且该算法具有更快的收敛速度. 相似文献
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该文提出了用于MC DS-CDMA系统中的两种SDCMA(最陡下降常模算法)盲检测方法,一种是SDCMA盲均衡算法,在此基础上,提出了另一种联合均衡和多用户检测的SDCMA盲算法。同时还将这两种算法与基于子空间的MMSE(最小均方误差)盲检测算法进行比较。仿真结果表明,这两种SDCMA算法的BER(误比特率)性能均优于子空间法,而且联合均衡和多用户检测的SDCMA盲算法利用同时对均衡权值向量和多用户检测器向量进行自适应更新,能较大程度地改善系统性能,是这3种盲算法中性能最佳的一个。 相似文献
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考虑实际的MC-CDMA上行链路,深入研究了基于RLS算法实现的MOE(RLS-MOE)盲自适应多用户检测,提出了MC-CDMA系统下一种基于子空间约束RLS的半盲多用户检测算法.在MOE盲多用户检测的基础上,利用小区内用户的已知扩频码设计了一种MOE半盲多用户检测器.将子空间方法和RLS算法相结合提出一种基于子空间约束的RLS 算法,使用该算法自适应得到MOE的权向量.本文算法利用所有已知用户的扩频码抑制了小区内用户的干扰,子空间约束的RLS 算法降低了噪声的影响,从而改善了系统的性能.修正的PASTd算法实现了信号的自适应跟踪,大大降低了计算量.仿真实验表明,本文算法的输出信干噪比和误码率性能优于RLS-MOE盲多用户检测,更接近于最优值. 相似文献
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恒模算法(CMA)是一种广泛应用于阵列处理、均衡、多用户检测中的盲算法.最小二乘恒模算法(LSCMA)由于其全局收敛性及稳定性受到关注.本文针对CDMA系统下行链路,基站知道小区内用户码字而小区外干扰用户码字未知的情形,提出一种适用的半盲LSCM多用户检测(MuD)算法.它将非盲多用户检测(本文中选用解相关MUD)与盲多用户检测技术(本文中选用LSCM检测器)相结合,首先根据小区内已知用户的信息,利用解相关MUD抵消小区内其它用户的干扰,接着利用LSCM算法抵消剩余的干扰.文中将SB-LSCM算法与已经提出的半盲解相关算法、LSCM算法和解相关算法进行了复杂度、SIR和BER性能的比较,并对SB-LSCM算法的SIR性能进行了理论分析.仿真结果表明SB-LSCM算法能够获得与半盲解相关相当的SIR的性能,但是其复杂度更低且在系统负荷大时能够获得优于半盲解相关算法的BER性能.另外,SB-SLCM算法能够获得较LSCM算法更快的收敛速度以及更加优良的性能. 相似文献
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Using the hypothesis that data transmitted by different users are statistically independent of each other, this paper proposes a fixed-point blind adaptive multiuser detection algorithm for Time-Hopping (TH) Impulse Radio (IR) Ultra Wide Band (UWB) systems in multipath channel, which is based on Inde-pendent Component Analysis (ICA) idea. The proposed algorithm employs maximizing negentropy criterion to separate the data packets of different users. Then the user characteristic sequences are utilized to identify the data packet order of the desired user. This algorithm only needs the desired user’s characteristic se-quence instead of channel information, power information and time-hoping code of any user. Due to using hypothesis of statistical independence among users, the proposed algorithm has the outstanding Bit Error Rate (BER) performance and the excellent ability of near-far resistance. Simulation results demonstrate that this algorithm has the performance close to that of Maximum-Likelihood (ML) algorithm and is a subopti-mum blind adaptive multiuser detection algorithm of excellent near-far resistance and low complexity. 相似文献
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In digital communication systems, the constant modulus algorithm (CMA) for blind multiuser detector has some disadvantage
such as slow convergence speed and weight phase rotation. In this paper, we put forward a novel receiver, which combines CMA
blind adaptive multiuser detection and particle swarm optimization (PSO) technique in frequency domain for multi-carrier direct
sequence code division multiple access (MC DS-CDMA) systems. By this approach we present an adaptive multistage structure
based on PSO technique. In this structure, the weights are obtained by PSO technique between the received signal and its estimate
through a CMA. The resulting weights contain reliability information for the hard decisions made in the previous stage. The
simulation results show that BER performance of the PSO-based CMA blind multiuser detector is superior to that of steepest
decreasing constant modulus algorithm (SDCMA), linearly constrained constant modulus algorithm (LCCMA), CMA based multiuser
detection and is worthy due to its significant detection performance to achieve desirable improvement in convergence speed
and tractability. 相似文献
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本文提出了一种加性高斯白噪声(AWGN)信道下,同步直扩码分多址(DS/CDMA)系统的基于LMK(最小平均峰度,Least Mean Kurtosis)准则的线性盲自适应多用户检测器.这种检测器的算法是一种具有较低计算量的基于高阶统计量的算法.分析证明了这种检测器的算法的收敛性和可以实现多用户信号的盲解相关.并对基于该准则的线性盲自适应检测器和基于LMS(最小均方,Least Mean Square)准则的检测器的收敛性能进行了仿真比较. 相似文献
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We discuss a synchronous direct-sequence code division multiple-access (DS-CDMA) system based on block spreading in the presence of frequency-selective fading. Note that block spreading, which is also known as chip interleaving, refers to a spreading of a data block sequence, which is obtained by dividing a data symbol sequence into consecutive blocks. For such a system, we develop a simple new receiver that completely removes the multiuser interference (MUI) without using any channel information. The MUI-free operation is obtained by the use of a shift-orthogonal set of code sequences on which this receiver is based. Within the framework of the MUI-free receiver, we further present a subspace deterministic blind single-user channel estimation algorithm. As a benchmark for the MUI-free receiver and the corresponding subspace deterministic blind single-user channel estimation algorithm, we consider the linear multiuser equalizer and the corresponding subspace deterministic blind multiuser channel estimation algorithm developed by Liu and Xu (1996) for a standard synchronous DS-CDMA system in the presence of frequency-selective fading. We show that the complexity of the MUI-free receiver using the corresponding subspace deterministic blind single-user channel estimation algorithm is much smaller than the complexity of the linear multiuser equalizer using the corresponding subspace deterministic blind multiuser channel estimation algorithm. We further show that the performance of the MUI-free receiver is comparable with the performance of the linear multiuser equalizer. This is for the case in which the channels are known as well as for the case in which the channels are estimated with the corresponding subspace deterministic blind channel estimation algorithm 相似文献
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多用户检测技术是扩频通信中解决多址干扰问题的一种重要技术。介绍了基于子空间盲多用户检测的原理。通过空间分解得到信号子空间,利用信号子空间的特征值和特征向量得到解相关多用户检测器,分析了其性能,并通过仿真证明其在有效性、抗远近效应等方面都较理想,是一种很有前途的多用户检测方法。 相似文献
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In this paper, we study the performance of subspace‐based multiuser detection techniques for multicarrier code‐division multiple access (MC‐CDMA) systems. We propose an improvement in the PASTd algorithm by cascading it with the classical Gram‐Schmidt procedure to orthonormalize the eigenvectors after their sequential extraction. The tracking of signal subspace using this algorithm, which we call OPASTd, has a faster convergence as the eigenvectors are orthonormalized at each discrete time sample. This improved PASTd algorithm is then used to implement the subspace blind adaptive multiuser detection for MC‐CDMA. We also show that, for multiuser detection, the complexity of the proposed scheme is lower than that of many other orthogonalization schemes found in the literature. Extensive simulation results are presented and discussed to demonstrate the performance of the proposed scheme. 相似文献