共查询到17条相似文献,搜索用时 62 毫秒
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异步CDMA移动通信系统采用分集接收的多用户检测器 总被引:1,自引:0,他引:1
在CDMA移动通信系统中,多址接入干扰可以通过多用户检测技术来消除,而分集接收可以减小信道衰落的影响,本文给出了一类应用解相关检测,天线分集,RAKE多径分集技术的接收机,并对这一类接收机的性能做了分析,结果表明,在上行链路中,应用多用户检测和分集接收能够极大提高接收机的性能。 相似文献
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本文针对频率选择性Rayleigh衰落信道,设计了一种CDMA多用户检测器分集结构,通过该结构,高斯信道多用户检测算法可以有效地应用到Rayleigh衰落信道中,仿真结果表明,分集合并实现的多用户中以显著改善衰落信道的误码性能,其处理多址干扰能力并不因分集而受到影响,另外,本文还对不同的合并以及不同的检测地作了性能上的比较。 相似文献
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首次提出将RAKE接收与判决反馈多用户检测相结合的接收方案,并对文献[1]提出的判决反馈多用户检测器加以改进,从而增加了检测器运算速度,节省所需内存,而且考虑了用户功率大小对判决反馈的影响,RAKE接收技术的采用,降低了误码率,使系统整体性能得到提高。 相似文献
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CDMA移动通信中的判决反馈多用户信号检测器 总被引:4,自引:0,他引:4
本文推导了一种具有线性计算复杂度的同步DS—CDMA系统多用户检测算法,由此形成的判决反馈检测器在性能上优于解相关检测器,与两级多用户检测器的性能相当,而实现起来则更为简单。数值结果表明,当接收到的干扰信号能量比有用信号能量高4dB以上时,判决反馈检测器的性能将接近单用户系统的性能,因而该检测器可有效地克服CDMA移动通信中的远近影响。 相似文献
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研究的是在服从瑞利分布受阴影效应影响的衰减信道中。采用直接序列扩频方式的CDMA无线移动通信系统的信道容量。用到的模型是以多用户检测宏分集(MDM)接收技术为基础建立的,他的特点是在阴影衰落信道中.在误码率较低的条件下,取得较高的数据传输速率。其信道容量可由每个小区中的用户数量来确定。 相似文献
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Wang Yan Cheng Shixin 《电子科学学刊(英文版)》1999,16(2):117-122
In CDMA mobile communication systems, multiple access interference can be canceled by multiuser detection technique. The Degradation by channel fading can be reduced by diversity reception. This paper investigates a family of multiuser receivers that combined decor-relating detection, antenna diversity and RAKE multipath diversity. The performance of the multiuser receivers is analyzed. The results demonstrate a significant increase in the performance of the receivers by using multiuser detection and diversity reception. 相似文献
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Shu-ming Tseng 《Wireless Personal Communications》2007,43(2):481-494
In a multicarrier direct-sequence code-division multiple access (MC DS CDMA) system, different fading channels for different
users and/or different carriers are correlated in general; thus a vector channel model is more appropriate than disjoint scalar
channel models. For multiuser MC DS CDMA systems, we propose (1) a generalized vector autoregressive model which accounts
for correlation between different user/carrier fading channels, (2) the use of a two-phased algorithm to obtain the proposed
model’s parameters, and (3) a receiver structure that consists of a generalized decorrelator followed by maximal-ratio combining
(MRC) of uncorrelated carrier channel outputs of each user. The estimated fading coefficients provide the necessary quantities
to MRC. The computer simulation results show that the proposed scheme has performance close to the case in which the channel
is perfectly known, and outperforms separate scalar channel estimation case. 相似文献
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Optimum multiuser detection for Code Division Multiple Access (CDMA) systems requires the solution of an NP-hard combinatorial optimization problem. It is well known that the computational complexity of the optimum multiuser detector is exponential with the number of active users in the system. In order to reduce the complexity of the optimum multiuser detection, we propose a Reduced Complexity Maximum Likelihood (RCML) algorithm that includes a set of novel certain boundary rules and characteristics. We investigate the performance and complexity tradeoffs for the RCML algorithm by conducting a set of simulations; Maximum Likelihood (ML) detection as a reference for performance comparisons, and relaxation based Semidefinite Programming (SDPB) algorithm as a reference for complexity comparisons. We show that the RCML algorithm is a promising algorithm for its computational savings over relaxation based algorithms in lightly-to-moderately loaded CDMA systems, and for its optimality in highly loaded CDMA systems. 相似文献