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2L支路SSC-MRC混合分集及其性能分析 被引量:2
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作者 李铮 张曙 郭冬梅 《应用科技》 CAS 2010年第12期14-18,共5页
分集合并技术是对抗多径衰落的有效手段,而常见的单纯分集合并技术如最大比合并(MRC)、等增益合并(EGC)、选择合并(SC)以及切换驻留合并(SSC)等在系统复杂度和系统性能之间存在矛盾;所以有必要寻找一种工程易于实现同时性能也可以接受... 分集合并技术是对抗多径衰落的有效手段,而常见的单纯分集合并技术如最大比合并(MRC)、等增益合并(EGC)、选择合并(SC)以及切换驻留合并(SSC)等在系统复杂度和系统性能之间存在矛盾;所以有必要寻找一种工程易于实现同时性能也可以接受的混合分集合并方式.在此将低成本、结构简单的SSC分集与最优性能的MRC分集结合,即SSC-MRC混合分集合并技术.推导了2L条独立同分布瑞利衰落信道下SSC-MRC混合分集的输出信噪比概率密度函数(PDF)以及BPSK信号下误码率表达式,还分析了门限选取对系统的影响.仿真实验表明,四支路SSC-MRC混合分集性能稍差于四支路MRC,但重要的是节省了2台接收机,大大减少了成本和系统复杂度. 展开更多
关键词 混合分集 切换驻留合并 最大比合并 平均输出信噪比
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分布式天线系统混合SC/MRC分集中断概率性能 被引量:1
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作者 李汉强 郭伟 郑辉 《电波科学学报》 EI CSCD 北大核心 2006年第5期756-762,共7页
在频率选择性复合Nakagami/lognormal衰落信道条件下,研究了层叠分布式天线系统(CascadeDistributedAntennaSystem——CDAS)采用混合SC/MRC分集的中断概率性能。针对中断概率性能,分析了多径密度函数(MultipathIntensityProfileMIP)衰... 在频率选择性复合Nakagami/lognormal衰落信道条件下,研究了层叠分布式天线系统(CascadeDistributedAntennaSystem——CDAS)采用混合SC/MRC分集的中断概率性能。针对中断概率性能,分析了多径密度函数(MultipathIntensityProfileMIP)衰减因子、空时分集维数、活动用户数、每比特平均接收信噪比以及衰落因子对系统性能的影响。仿真表明CDAS系统可以有效对抗衰落,提高系统容量,削弱对数正态阴影衰落影响。 展开更多
关键词 分布式天线系统 混合SC/MRC分集 Nakagami/jlognormal复合衰落 中断概率
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考虑混合SC/MRC分集的层叠分布式天线系统SER性能分析
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作者 李汉强 郭伟 郑辉 《电子学报》 EI CAS CSCD 北大核心 2006年第4期599-604,共6页
针对Nakagam i/lognorm al复合衰落信道,研究了层叠分布式天线系统(Cascade D istributed Anten-na System-CDAS)在CDMA网络中的平均误符号率性能.推导出了采用混合SC/MRC分集接收机的层叠分布式天线系统平均误符号率性能公式.利用推导... 针对Nakagam i/lognorm al复合衰落信道,研究了层叠分布式天线系统(Cascade D istributed Anten-na System-CDAS)在CDMA网络中的平均误符号率性能.推导出了采用混合SC/MRC分集接收机的层叠分布式天线系统平均误符号率性能公式.利用推导出的平均误符号率表达式,分析了多径密度函数(M ultipath IntensityProfile-M IP)衰减因子、空时分集维数、活动用户数以及阴影衰落因子对平均误符号率性能的影响.仿真表明层叠分布式天线系统可以有效对抗衰落,提高系统容量以及削弱对数正态阴影衰落的影响. 展开更多
关键词 分布式天线系统 混合SC/MRC分集 Nakagami/lognormal复合衰落
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三维MIMO信道物理模型的统计特征 被引量:1
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作者 海凛 张业荣 《南京邮电大学学报(自然科学版)》 2009年第6期38-42,共5页
提出以散射矩阵来概括并简化电波传播过程中散射体对电磁波的影响,并对传统的距离分集和极化分集多入多出(MIMO)信道模型进行扩展,建立了一种可以应用于各种分集情况的三维通用MIMO物理信道模型。再以此模型为基础,对三维环境中的MIMO... 提出以散射矩阵来概括并简化电波传播过程中散射体对电磁波的影响,并对传统的距离分集和极化分集多入多出(MIMO)信道模型进行扩展,建立了一种可以应用于各种分集情况的三维通用MIMO物理信道模型。再以此模型为基础,对三维环境中的MIMO信道统计特征进行了研究,推导出任意情况下交叉极化鉴别度(XPD)和子信道间相关性的计算方法,并进行了仿真验证。仿真结果表明从文中所提出信道模型提取得到的统计特征与理论分析的结果是相符的。 展开更多
关键词 MIMO 混合分集 物理信道模型 XPD 相关性
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Separation of inhomogeneous blended seismic data 被引量:2
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作者 刘强 韩立国 +2 位作者 陈竞一 陈雪 张显娜 《Applied Geophysics》 SCIE CSCD 2015年第3期327-333,466,共8页
The frequencies of sources involved m conventional blended acquisition are the same. Each source transmits the full frequency band, and in general, significant effort is required to successfully produce and operate wi... The frequencies of sources involved m conventional blended acquisition are the same. Each source transmits the full frequency band, and in general, significant effort is required to successfully produce and operate wideband sources. To solve this problem, inhomogeneous blended or decentralized blended acquisition is used, in which the dominant frequency and bandwidth of the source units in a blended array are not equal. When the inhomogeneous and conventional blending acquisitions adopt the same geometry and separation methods, the former has low signal-to-blending noise ratio. Therefore, we present a new separation method for such blended acquisition based on the synchrosqueezed wavelet transform. The proposed method offers better separation quality and decreases the computation time to approximately 1/3. 展开更多
关键词 Inhomogeneous blended acquisition synchrosqueezed wavelet transform deblending
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Energy Efficient Resource Allocation in Timesharing Multiuser Systems with Hybrid Energy Harvesting Transmitter 被引量:1
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作者 Jinming Hu Wei Heng +1 位作者 Guodong Zhang Xiang Li 《China Communications》 SCIE CSCD 2017年第8期83-92,共10页
An energy effi cient resource allocation scheme in timesharing multiuser system with a hybrid energy harvesting transmitter is studied in this paper. Specially, the operation energy of system is supplied by constant e... An energy effi cient resource allocation scheme in timesharing multiuser system with a hybrid energy harvesting transmitter is studied in this paper. Specially, the operation energy of system is supplied by constant energy and energy harvesting, which harvests energy from external environment. Our goal is to maximize the energy effi ciency of timesharing multiuser systems by considering jointly allocation of transmission time and power control in an off-line manner. The original nonconvex objective function is transformed into convex optimization problem via the fractional programming approach. Then, we solve the convex problem by Lagrange dual decomposition method. Simulation results show that the proposed energy efficient resource allocation scheme has a better performance than the scheme which decomposes optimization problem into two parts(power allocation, time allocation) to solve iteratively. 展开更多
关键词 energy harvesting energy efficient resource allocation fractional programming
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Experimental study on gas–liquid dispersion and mass transfer in shear-thinning system with coaxial mixer 被引量:1
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作者 Baoqing Liu Yijun Zheng +3 位作者 Ruijia Cheng Zilong Xu Manman Wang Zhijiang Jin 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第9期1785-1791,共7页
The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas hold... The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas holdup, relative power demand, and volumetric mass transfer coefficient under different conditions were compared. The results show that, the increasing stirring power or gas flow rate is beneficial in promoting the overall gas holdup and volumetric mass transfer coefficient, while the increasing system viscosity weakens the mass transfer in a shearing–thinning system. Among the three turbines, the six curved-blade disc turbine(BDT-6) exhibits the best gas pumping capacity; the six 45° pitched-blade disc turbine(PBDT-6) has the highest volumetric mass transfer coefficient at the same unit volume power. 展开更多
关键词 Non-Newtonian fluids Coaxial mixer Gas holdup Relative power demand Mass transfer
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Self-organizing dual clustering considering spatial analysis and hybrid distance measures 被引量:10
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作者 JIAO LiMin LIU YaoLin ZOU Bin 《Science China Earth Sciences》 SCIE EI CAS 2011年第8期1268-1278,共11页
Dual clustering performs object clustering in both spatial and non-spatial domains that cannot be dealt with well by traditional clustering methods.However,recent dual clustering research has often omitted spatial out... Dual clustering performs object clustering in both spatial and non-spatial domains that cannot be dealt with well by traditional clustering methods.However,recent dual clustering research has often omitted spatial outliers,subjectively determined the weights of hybrid distance measures,and produced diverse clustering results.In this study,we first redefined the dual clustering problem and related concepts to highlight the clustering criteria.We then presented a self-organizing dual clustering algorithm (SDC) based on the self-organizing feature map and certain spatial analysis operations,including the Voronoi diagram and polygon aggregation and amalgamation.The algorithm employs a hybrid distance measure that combines geometric distance and non-spatial similarity,while the clustering spectrum analysis helps to determine the weight of non-spatial similarity in the measure.A case study was conducted on a spatial database of urban land price samples in Wuhan,China.SDC detected spatial outliers and clustered the points into spatially connective and attributively homogenous sub-groups.In particular,SDC revealed zonal areas that describe the actual distribution of land prices but were not demonstrated by other methods.SDC reduced the subjectivity in dual clustering. 展开更多
关键词 dual clustering DATAMINING self-organizing feature map Voronoi diagram
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