共查询到19条相似文献,搜索用时 63 毫秒
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空时编码(STC)技术将天线阵列信号处理和信道编码技术联合起来实现无线信道容量的有效增加。为了抑制空时分组编码(STBC)系统的共道用户干扰,对低复杂度的多用户检测算法进行研究,该文提出了一种STBC系统的迭代(turbo)多用户接收机。该接收机由一个软入软出(SISO)基于均值的软判决多用户检测器(Soft Decision Multi-User Detector, SDMUD)和一组SISO Turbo信道解码器构成。两者之间通过迭代交换外信息,精确地估计用户信号。仿真结果表明这种接收技术经3次迭代后性能改善约2dB,并且系统性能会随着接收天线的增多而得到明显提高,从而大大增加系统容量。 相似文献
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本文介绍了一种将正交频分复用(OFDM)技术和码分多址(CDMA)技术相结合的多载波CDMA (MC-CDMA)系统,分析了MC-CDMA系统的发射端和接收端的结构,建立了MC-CDMA系统的信号模型,详细分析了MC-CDMA中的多址干扰形式,以及针对MC-CDMA系统的多用户检测原理,提出了一种基于最小误码率准则的多用户检测算法。理想的基于最小误码率准则的多用户检测算法在实际中难于实现,本文采用估计概率密度函数的方法,推导出了一种自适应实现的最小误码率多用户检测算法。仿真结果表明,该算法能够有效抑制多址干扰,降低误码率,同时,该算法还具有比基于最小均方误差准则的多用户检测器更低的误码率的优点。 相似文献
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阐述了智能天线的基本原理,指出码分多址系统基站中采用智能天线技术可能抑制多址干扰。在总结分析了目前各种波束形成技术的基础上,着重介绍了一种适用于移动无线通信环境的阵列权值调整准则-最大接收信号准则,利用此准则和相应算法。提出了一种带智能天线的新型最小均方误差多用户检测器,理论分析证明了采用新型检测器后系统容量显增加,仿真实验表明,新型检测器的误码性能大大优于改进前的检测器。 相似文献
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同时考虑系统性能和运算量,将多步联合检测和迭代多用户检测技术结合起来,提出了多步迭代多用户检测技术。相对于单纯的MSJD,系统性能将大大提高;相对于单纯的迭代多用户检测,运算量将大大减少。 相似文献
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研究了Turbo(并行级联码)译码原理及其在CDMA多用户检测中的应用。文中简述了Turbo译码原理及逐符号最大后验算法(symbol-by-symbol MAP),并将Turbo译码原理应用于CDMA系统的多用户检测,提出了基于Turbo译码原理的多用户检测接收机方案,通过计算机仿真验证该方案的性能。结果表明,本文所提出的方案经过4次迭代之后,其误码率接近单用户界,说明这种接收机可去除多址干扰(MAI)的影响。 相似文献
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一种低复杂度的Turbo多用户检测技术 总被引:3,自引:0,他引:3
基于Turbo原理,提出了一种适合于同步DS-CDMA系统的迭代多用户接收机结构,它通过在反复迭代的软输入出多用户检测器和一组信道译码之间获得连续的软判决,从而得到一种低复杂度的多用户检测算法-软MMSE干扰消除。 相似文献
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基于NLMS的CDMA盲自适应多用户检测算法研究 总被引:1,自引:0,他引:1
多用户检测是抑制DS-CDMA系统多址干扰最有效的技术之一。由于所需的先验知识仪有期望用户的地址码,盲多用户检测技术的研究尤受重视。最小输出能量(MOE)准则被广泛用于盲线性多用户检测。目前已提出的该类检测器多采用LMS或RLS算法。本文则研究基于NLMS算法的盲自适应检测技术,并进一步提出盲自适应变步长NLMS检测器和参数可变的盲自适应变步长NLMS检测器。它们具备很好的收敛速度和跟踪能力,以及较高的输出信干比,同时计算复杂度仅为O(3N)或O(4N),非常适合硬件实现。 相似文献
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Tobias Weber Jochen Oster Martin Weckerle Paul Walter Baier 《AEUE-International Journal of Electronics and Communications》2002,56(2)
In this paper the novel detection scheme multi-step joint detection for TD-CDMA mobile radio systems is presented. Multi-step joint detection uses the turbo principle for iteratively improving data detection. Extrinsic information obtained by FEC-decoding in a previous step is used for a joint reduction of interference and improvement of asymptotic efficiency of the linear multiuser detector. Multi-step joint detection helps to overcome the problems of small asymptotic efficiencies present in linear multiuser detectors like the zero forcing equalizer in TD-CDMA mobile radio systems in the case of high system loads. Simultaneously complexity is much lower than that of optimum nonlinear multiuser detectors based on the Viterbi algorithm. As an alternative to simulations the performance of multi-step joint detection can be theoretically determined under certain not too restrictive assumptions. Both approximate and simulative performance results are presented in the paper. It is shown that in typical mobile radio systems the required SNR at the receiver input can be reduced by approximately 10 dB compared to linear multiuser detection. Thus, multi-step joint detection helps to increase the permissible number of mobile stations per cell or to decrease the required cluster size in TD-CDMA mobile radio systems and thus improves spectrum efficiency and capacity. 相似文献
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Multiuser detectors for asynchronous multirate code-division multiple-access (CDMA) systems are considered. A multirate CDMA system model able to fit several system concepts in the same framework is presented. The performance of the multi-code (MC) system with one processing gain and the multiple processing gain (MPG) system is compared. Upper bounds for the expected value of the asymptotic multiuser efficiency of the decorrelating detector for a synchronous multirate CDMA system with three effective users are derived for a system with one and two processing gains. The numerical results show that the performance of the decorrelating detector for MC and MPG systems do not differ significantly. The bit error rates (BER) of the decorrelating, parallel interference canceler (PIC) and groupwise serial interference canceler (GSIC) with either PIC or decorrelator within the group are compared. The results show that the decorrelating and the GSIC detectors yield the best performance. For all interference cancellation schemes the BER saturates at high SNRs due to decision errors degrading the multiple-access interference (MAI) estimates. 相似文献
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1 IntroductionIthasbeenshownthatthecapacityofwirelesscommunicationsystemscanbeincreaseddramatical lybyemployingmultipletransmittingandreceivingantennas.Space timecodinghasbeenpaidmoreat tentionrecentlybecauseitisaneffectivewaytoex ploitspatialandtemporaldiversity[1~2 ] .Despitealossincodingadvantage,space timeblockcodingcanofferthemaximumdiversitygainbasedononlythelinearprocessingatthereceiver[3~ 4] andhasbeenproposedtobeusedin 3Gsystems.InterferencesuppressionismorechallenginginCDMAsyste… 相似文献
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首先分析了CDMA移动通信系统中采用多用户检测的必要性 ,然后介绍了各种多用户检测技术的工作原理 ,对各种多用户检测技术的特点进行了分析比较 ,最后提出了目前多用户检测技术的一些最新发展方向。 相似文献