共查询到19条相似文献,搜索用时 62 毫秒
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基于ε逼近算法的CDMA盲自适应多用户检测 总被引:4,自引:0,他引:4
把码分多址通信系统的盲多用户信号检测问题转化为一个带约束的二次规划问题,利用二次规划问题的ε逼近算法给出了一种新的CDMA盲自适应多用户检测方法,仿真结果表明,该算法不但具有较强的多址干扰抑制性能,而且具有很快的收敛速度。对于时变信道特别适用。 相似文献
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CDMA系统存在很强的多址干扰,且实际无线环境一般为多径信道。文章介绍了基于卡尔曼滤波的、且适用于多径信道的盲自适应多用户检测算法,并与基于LMS、RLS滤波的自适应多用户检测算法进行了比较。 相似文献
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多用户检测中盲自适应算法的研究 总被引:2,自引:0,他引:2
多用户检测中的盲目适应算法包括上输出能量(MOE)算法、Sato算法、恒模算法(CMA)和约束恒模算法(C-CMA)。本文比较了以上算法和均方误差(MSE)算法的收敛性能,仿真表明在保证收敛的条件下,CMA或C-CMA算法具有收敛速度快、稳态性能好的优点,因此实际系统中可以先脾MOE算法,当达到稳态后,转到CMA或C-CMA算法上以提高稳态性能,且计算复杂度只有O(N)。 相似文献
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一种新的盲自适应多用户检测算法 总被引:1,自引:0,他引:1
多址干扰引发严重的远 /近问题。本文提出一种新的代价函数 :差分平均输出能量(DMOE) ,并设计了适用于DS/CDMA系统的盲多用户检测算法。理论分析和数值模拟表明该算法的收敛性能及误码性能均优于MOE检测器 相似文献
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本文在直接序列/码分多址(DS/CDMA)系统盲检测自适应梯度算法(BAG)的基础上,提出了一种多用户检测盲自适应梯度算法的改进算法(IBAG).BAG算法包括自适应梯度算法(TBAG)和时变自适应梯度算法(TIBAG),TBAG算法的跟踪特性较好,但起始收敛特性不好;TIBAG算法的收敛特性较好,但跟踪特性较差,几乎不具备跟踪能力.本改进算法结合了这两种自适应梯度算法的优点,在不增加算法复杂度的前提下,使其收敛性和跟踪特性较BAG算法有所提高. 相似文献
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把码分多址(CDMA)信道等效为一多输入多输出(MMO)信道模型,用子空间分解的盲估计方法进行信道估计,而且估计出信号子空间特征向量,利用信道参数和信号子空间的特征向量构建解相关和最小均方误差(MMSE)两类线性检测器,能同时消除码间干扰(ISI)和多址干扰(MAI)。 相似文献
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1 IntroductionMultiuserDetection (MUD)ismainlyappliedinCDMAtocancelthemultiaccessinterference.Thesingle usermatchedfilterorrakereceivertreatstheinterferencefromotherusersasnoise ,butMUDtakesadvantageoftheotheruser’sinterference[1 ].BlindadaptiveMUDhasbeent… 相似文献
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Buzzi Stefano Krishnamurthy Vikram Lops Marco Poor H. Vincent 《Wireless Personal Communications》2003,27(4):293-320
The problem of blind adaptive multiuser detection in multirateCDMA systems is considered. Indeed, since symboldetection in multirate CDMA systems requires periodicallytime-varying processing of the observables, classical LMS and RLSadaptive algorithms, which assume that the solution to be trackedis time-invariant or slowly time-varying, are not suited for blindadaptive multiuser detection in a multirate system. While a cyclicRLS algorithm has recently appeared in the literature, thispaper focuses on the development of LMS-based cyclic filteringalgorithms. In particular, cyclic versions of the standard LMSalgorithm, of the LMS algorithm with iterate averaging and of theLMS algorithm with adaptive step-size are derived. Interestingly,the last two algorithms are shown to exhibit a convergence speed close to thatof the cyclicRLS procedure, but with an order of magnitude lower computationalcomplexity.An adaptive procedure for the automatic selection ofthe algorithm periodicity is also presented, which is based on aminimum mean-output-energy criterion, and that obviates theneed for knowledge of the transmitted data-rates from theinterfering signals.Moreover, the case of known multipathfading channels is also examined. In particular, it is shown that theproposed cyclic LMS algorithms can be used to achieve RLS-likeperformance also in the presence of multipath distortion.Extensive computer simulation results, along with some analyticalconvergence results, confirmthat the proposed algorithms are effective and achieve very satisfactoryperformance. 相似文献
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多径CDMA信道下最小均方盲空时多用户检测 总被引:1,自引:0,他引:1
本文首先在码片匹配滤波的基础上为多径CDMA信道环境的接收机提出四种数据选择方案,分析了各种数据方案对多址干扰与码间干扰的影响;接着提出了基于Rosen梯度投影实现的最小均方盲空时多用户检测方法并分析了四种数据选择方案对其运算复杂度的影响;最后通过仿真实验结果的分析比较给出较合理的实现方法,该方法在降低运算量具有一定的优势,因而更加具有实用意义. 相似文献
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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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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