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下行增强MIMO是LTE-Advanced的关键技术之一,文章讨论了LTER8和R9的多用户MIMO的传输模式,并且就LTE-Advanced中的多用户MIMO的主要问题进行了讨论。比较了各种可能的导频设计,下行控制信令、反馈及增强的码本设计方法,探讨了多用户MIMO适用的场景以及每个用户支持多于两个layer的可能性,并介绍了标准化进展情况。 相似文献
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对基于中继传输的LTE-Advanced下行系统中的数据包传输机制进行了分析,并提出基于最大时延优先调度准则(MLWDF,modified largest weighted delay first)的分布式中继系统Voice over Internet Protocol(VoIP)业务调度方案.基于LTE-Advanc... 相似文献
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多点协同中继的无线传输技术作为LTE-Advanced系统中主要的新技术,对于扩大网络边缘覆盖、保证边缘用户服务质量有着至关重要的作用。文章主要介绍了多址接入、多用户协作通信、无线衰落信道和IDMA这几个多点协同中继无线传输中的关键技术。 相似文献
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LTE-Advanced关键技术演进趋势 总被引:5,自引:2,他引:3
文章对LTE-Advanced的定位及需求进行了分析,对LTE-Advanced技术和网络演进趋势进行了研究,指出LTE-Advanced的重点工作方向将放在RRM技术和网络架构优化方面。 相似文献
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中首先回顾了商用移动通信系统的发展历程,简单介绍了LTE和LTE-Advanced技术标准,然后重点研究了LTE-Advanced技术标准中几项关键技术,最后总结了LTE-Advanced技术标准的发展趋势。 相似文献
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LTE-Advanced是基于LTE的增强与演进,载波聚合技术是LTE-Advanced的关键技术之一。文章介绍了LTE-Advanced载波聚合技术的背景、技术构成及在3GPP中的标准化进程,并总结了该技术的下一步研究重点与发展方向。 相似文献
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The authors investigate the use of conditioning events (or contexts) in improving the performances of known compression methods by building a source model with multiple contexts to code the decorrelated pixels. Three methods for reversible compression, namely DPCM (differential pulse code modulation), WHT (Walsh-Hadamard transform), and HINT (hierarchical interpolation), employing, respectively, predictive decorrelation, transform decorrelation, and multiresolution decorrelation, are considered. It is shown that the performance of these methods can be enhanced significantly, sometimes even up to 40%, by using contexts. The enhanced DPCM method is found to perform the best for MR and UT (ultrasound) medical images; the enhanced WHT method is found to be the best for X-ray images. The source models used in the enhanced models employ several hundred contexts. 相似文献
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低照度图像存在细节模糊、对比度低等问题.针对这些问题,本文提出一种低照度彩色图像增强算法.首先建立梯度稀疏和最小平方约束模型,将图像分解为结构层和细节层;然后采用提出的多尺度边缘保护细节增强算法强化图像的细节信息并滤波;最后把细节增强的图像经改进的Retinex算法映射,最终得到细节增强、亮度适宜、对比度较强的修复图像.实验结果表明,主观上:图像细节增强,亮度适宜;客观上:结构层图像的一维像素线性图显示其平滑特性效果较好,细节增强图的NIQE(5.5202)、BRISQE(31.1893)和PSNR(25.3625)特征较好,修复图像的熵值(7.4421)、边缘强度(128.3231)和平均亮度(121.1827)较好.本文算法实现了对低照度图像的有效分解及细节增强,并提高了图像综合质量. 相似文献
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Photoinduced Anisotropic Supramolecular Assembly and Enhanced Charge Transport of Poly(3‐hexylthiophene) Thin Films
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Mincheol Chang Jiho Lee Nabil Kleinhenz Boyi Fu Elsa Reichmanis 《Advanced functional materials》2014,24(28):4457-4465
The self‐organization of organic polymer semiconductors into ordered supramolecular assemblies commensurate with efficient charge transport is achieved by tuning a range of process parameters (e.g., film deposition method (spin vs drop cast), solvent boiling point (low vs high boiling point), polymer‐dielectric interface treatment, and post‐deposition processing (solvent vapor or thermal annealing)). However, these strategies present limitations for large‐scale high‐throughput processing due to associated pre‐ and/or post semiconductor deposition steps. Here, photoinduced anisotropic supramolecular assembly of P3HT chains in solution is demonstrated. UV irradiation provides for enhanced intramolecular ordering of solubilized polymer chains, and thereby effects formation of anisotropic supramolecular polymer assemblies via favorable π–π stacking (intermolecular interaction). Molecular ordering is thus dramatically enhanced with concomitant, enhanced charge transport characteristics of corresponding films. Additional pre‐ and/or post treatments are avoided. 相似文献
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A new detection technique of gas concentration with optical spectrum absorption at near-IR wavelength 总被引:1,自引:0,他引:1
Wavelength modulation technique(WMT) and active intracavity technique(ACIT) are first introduced in this paper,which are used to realize the concentration detection of methane and acetylene respectively.When ACIT is combined with wavelength sweep technique(WST),the detection sensitivity of acetylene can be enhanced sharply.When ACIT is combined with WST and WMT,the detection sensitivity of acetylene can be enhanced further. 相似文献
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An enhanced differential chain coding (EDCC) scheme is developed for transmission of high-quality line graphics. Experiments showed that, compared to DCC with a resolution of the enhanced graphics adapter (EGA: 640×350 pixels), EDCC with a resolution of 2100×1536 pixels gives a much higher quality with a modest extension in storage and transmission capacity 相似文献
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CobraNet技术在广播总控系统中的应用 总被引:1,自引:1,他引:0
CobraNet(眼镜蛇网络)是当前使用比较广泛的多通道数字音频传输技术之一,它利用成熟的快速以太网来传输和分配实时、非压缩的数字音频信号.此技术可应用于电台的总控系统中,作为音频信号传输交换的备份路由,从而提高了电台主控系统节目传输交换的安全性,同时又降低了管理成本,提高了对音频信号的监控监视能力,是一种值得大力推广使用的技术. 相似文献
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为了进一步提高数字通信的可靠性,在两个三维8PSK星座图的基础上设计了一种增强型六维64PSK调制格式.相比传统的二维64PSK、64QAM调制格式,在功率归一化的条件下,增强型六维64PSK调制格式的最小欧氏距离(Minimum Euclidean Distance,MED)变得更大,而且能够分别获得21.6 dB和11.8 dB的解调增益.在最大化最小欧氏距离的过程中没有使用重复的算法,因此新方法的计算复杂度较低,这种增强型六维64PSK调制格式非常适合完成一个高可靠性的数字通信系统. 相似文献
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Beamspace Root-MUSIC for minimum redundancy linear arrays 总被引:1,自引:0,他引:1
Zoltowski M.D. Silverstein S.D. Mathews C.P. 《Signal Processing, IEEE Transactions on》1993,41(7):2502-2507
Beamspace Root-MUSIC, a computationally efficient beamspace implementation of Root-MUSIC developed recently for use in conjunction with a uniformly spaced linear array (ULA), is discussed. Computationally efficient methods for using beamspace Root-MUSIC in conjunction with a minimum redundancy linear array (MRLA) for both the narrowband and wideband cases are developed. The MRLA is attractive in that it offers enhanced detection performance and enhanced resolution capability relative to a ULA having the same number of elements 相似文献
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恶化非归零码信号的全光时钟恢复 总被引:3,自引:0,他引:3
全光时钟提取结构应对输入信号的恶化程度有一定的容忍度.在一种半导体光放大器(SOA) 啁啾光纤布拉格光栅(CFBG) 受激布里渊散射(SBS)的方式实现非归零(NRZ)码信号的全光时钟提取结构中,半导体光放大器和啁啾光纤布拉格光栅共同作用实现了非归零码信号的时钟分量增强,基于受激布里渊散射的全光时钟提取结构提取出非归零码的光时钟信号.实验通过对不同恶化程度的非归零码信号的时钟提取比较发现,恶化信号的信噪比是影响光时钟提取的关键.输入非归零码信号的信噪比越差,光时钟信号光谱的噪声水平越高,提取出的光时钟信号的幅度越低.当时钟增强非归零码信号的时钟数据抑制比低于-10 dB时,无法实现非归零码信号的时钟提取. 相似文献
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《Microwave and Wireless Components Letters, IEEE》2006,16(11):624-626
An enhanced composite right/left-handed (CRLH) transmission line (TL) is presented in this letter. This TL, designed in microstrip technology, is implemented by means of a new improved interdigital capacitor (IDC), the so-called wire bonded IDC (WBIDC). The use of the WBIDC broadens the frequency band where the CRLH TL can be considered as a TL. A conventional 70-Omega CRLH TL (using IDCs) has been compared, by full-wave simulation and measurements, with its enhanced counterpart (using WBIDCs). In addition, this enhanced CRLH TL has been used to design a CRLH diplexer which presents several advantages over standard CRLH coupled lines (using IDCs). The diplexer response has been verified by means of a full-wave electromagnetic solver 相似文献