共查询到17条相似文献,搜索用时 187 毫秒
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该文在二发一收的空时分组码(STBC)单载波块传输系统中,提出一种空时和多径分集合并接收算法。通过基于STBC的单载波频域均衡(STBC-SC-FDE)算法得到对发送信号的估计,以此和信道状态信息(CSI)分离接收信号中的各多径分量,对各多径分量分别采用STBC合并,最后再将各多径分量的合并输出结果按照最大比(MRC)的方式进行合并,从而实现空时二维RAKE接收。该算法在较低的计算复杂度情况下,可以同时获得发射分集和多径分集,Monte Carlo仿真验证了该算法的性能。 相似文献
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为了充分利用瑞克(RAKE)接收机的多径能量利用效果和智能天线(SA)的定向收发作用,研究了RAKE接收机和智能天线的联合使用,提出了基于智能天线的定向二维(2D)RAKE接收机模型,给出了定向2D-RAKE接收机分别在射频、中频和基带的实现框图、工作原理和输出信号表达式,并对它们的性能以及工程实现做了分析讨论。指出基带定向二维RAKE接收机由于可以在基带上通过幅度加权来实现信号的定向收发,其优点是可以利用目前比较成熟的基带信号处理技术,但是由于不能利用相干解调作用来抑制多径干扰(MPI)和多用户干扰(MAI),存在噪声放大问题;射频定向二维RAKE接收机的信噪比增益最大,但工程实现难度较大;中频定向二维RAKE接收机则具有较高的性价比。 相似文献
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提出了一种用于正交空时分组码(OSTBC:Orthogonal Space-Time Block Code)多发射天线多接收天线系统的盲自适应接收机.该方法主要利用了正交空时分组码的内在特性,给出了一个针对正交空时分组码多发射天线多接收天线系统的无约束代价函数,分析了该函数的全局最小值点.利用该无约束代价函数,通过投影逼近方法给出了递推最小二乘(RLS)自适应算法实现.仿真结果表明:该接收机可以很好的跟踪衰落信道的变化,在不利用导频信号的情况下很好的还原出原始的传输信号. 相似文献
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智能天线在无线通信中的应用分析 总被引:2,自引:0,他引:2
为了在复杂的电磁传播环境中保证信号传输的可靠性,智能天线技术逐渐得到人们的广泛关注。智能天线的概念使得天线从传统的单一场路转换器件发展成具有一定信号处理功能,并和接收机后端处理紧密结合的天线系统。本文介绍并分析了传统自适应天线及空时二维信号处理技术在蜂窝系统中的应用,对用于时分多址系统的自适应波束形成器及用于码分多址系统的2D RAKE进行了仿真,并通过仿真说明了基于空时二维处理的智能天线系统在性能上的优越性。 相似文献
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Song Rongfang Bi Guangguo 《电子科学学刊(英文版)》2001,18(2):140-146
Quadratic programming models for integrated space-time interference suppression in CDMA systems are proposed in this paper. The models integrate the advantages of smart antenna and RAKE receiver, mitigate multiuser access interference (MAI) and interchip interference (ICI), and combine multipath components. The zero-forcing conditions are derived. Neural network implementation of the models is also studied. 相似文献
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Transmitter diversity in the downlink of code-division multiple-access (CDMA) systems achieves similar performance gains to the mobile-station receiver diversity without the complexity of a mobile-station receiver antenna array. Pre-RAKE precoding at the transmitter can be employed to achieve the multipath diversity without the need of the RAKE receiver at the mobile station. We examine feasibility of several transmitter diversity techniques and precoding for the third-generation wideband CDMA (WCDMA) systems. In particular, selective transmit diversity, transmit adaptive array and space-time pre-RAKE (STPR) techniques are compared. It is demonstrated that the STPR method is the optimal method to combine antenna diversity and temporal precoding. This method achieves the gain of maximum ratio combining of all space and frequency diversity branches when perfect channel state information is available at the transmitter. We employ the long range fading prediction algorithm to enable transmitter diversity techniques for rapidly time varying multipath fading channels. 相似文献
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A space-time (ST) receiver is proposed for combating the cochannelinterference (CCI) and intersymbol interference (ISI) in a frequency-selectivemultipath environment. The scheme involves two stages. First, a set ofadaptive beamformers pointed at a prescribed angular sector in space isconstructed on an oversampled antenna array, each providing effectivesuppression of CCI and reception of desired signals. Second, afractionally-spaced decision feedback equalizer (DFE) follows to eliminate theISI left in beamformer outputs. In particular, both the beamformers and DFEcan be realized in the form of a generalized sidelobe canceller (GSC) with theaid of channel estimation, and partial adaptivity is incorporated for reducedcomplexity processing and improved convergence. The proposed ST receiver canbe employed as a multi-beam smart antenna system which is suitable forcellular communications. Computer simulations demonstrate that it can achievenearly the same performance as the optimal ST minimum mean square error (MMSE)DFE with a much lower implementation complexity. 相似文献