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Queue-aware energy-efficient scheduling and power allocation with feedback reduction in small-cell networks

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science China(Information sciences) 2018年第4期61卷 246-252页

作者： Hongxin WEI Yunzhou LI Limin XIAO Shidong ZHOU State Key Laboratory on Microwave and Digital Communications Tsinghua National Laboratory Information Science and Technology Department of Electronic Engineering Tsinghua University

In small cell networks(SCNs),the path loss becomes smaller,and energy efficiency could be improved.If plenty of small base stations(BSs)are deployed,the energy consumption of each BSs can be small enough to make the t... 详细信息

关键词： CSI Queue-aware energy-efficient scheduling and power allocation with feedback reduction in small-cell networks

TWO-STAGE ESTIMATION FOR SEEMINGLY UNRELATED NONPARAMETRIC REGRESSION MODELS

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Journal of Systems science & Complexity 2007年第4期20卷 509-520页

作者： Jinhong YOU Shangyu XIE Yong ZHOU Department of Biostatistics University of North Carolina at Chapel Hill Chapel Hill NC 27599-7400 USA. Institute of Applied Mathematics Chinese Academy of Sciences Beijing 100080 China

这篇论文涉及估计的问题看起来无关(苏) 非参量的回归当模特儿。作者建议一个新方法估计未知函数，它是在纵的数据框架的二阶段的过程的扩展。作者证明结果的评估者是 asymptotically 正常的；比那些更有效基于仅仅单个回归方程。一些... 详细信息

这篇论文涉及估计的问题看起来无关(苏) 非参量的回归当模特儿。作者建议一个新方法估计未知函数，它是在纵的数据框架的二阶段的过程的扩展。作者证明结果的评估者是 asymptotically 正常的；比那些更有效基于仅仅单个回归方程。一些模拟研究在 asymptotic 结果的支持被给。从进行中的环境流行病的研究的一个真实数据被用来说明建议过程。

关键词：渐近正态性两阶评估非参数衰退模型系统理论

Sectorization based pilot reuse for improving net spectral efficiency in the multicell massive MIMO system

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science China(Information sciences) 2016年第2期59卷 97-111页

作者： Jiahui LI Limin XIAO Xibin XU Shidong ZHOU State Key Laboratory on Microwave and Digital Communications Tsinghua National Laboratory for Information science and Technology Department of Electronic Engineering Tsinghua University

A sectorization method using the uniform circular array(UCA) is proposed to improve the net spectral efficiency(SE) of the multicell massive MIMO system, which is an important index for evaluating the performance of a communication system. We derive the ergodic achievable uplink net SE per cell of a general sectorized system and obtain its deterministic approximation based on the large random matrix theory.Different weight matrices are considered for the sectorized system and the one with the best performance is utilized for further analysis. The consistency of the deterministic approximation with the result of Monte-Carlo simulation is proved at the same time. At last, numerical results indicate that the net SE per cell can be greatly improved compared to the conventional multicell massive MIMO system, which validates the effectiveness of the sectorization method. Moreover, comparisons with other pilot reuse methods are also made in this paper.

关键词： massive MIMO multicell net SE pilot reuse sectorization UCA

Distribution characteristics of inertial sediment particles in the turbulent boundary layer of an open channel flow determined using Voronoi analysis

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International Journal of Sediment research 2017年第3期32卷 401-409页

作者： Xin Liu Chunning Ji Xiaoli Xu Dong Xu John J.R.Williams State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University Tianjin research Institute for Water Transport Engineering M.O.T. State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University School of Engineering and Materials science Queen Mary University of London

This paper presents the numerical investigation of the distribution of inertial sediment particles in the turbulent boundary layer of an open channel flow with the particle Stokes number ranging from 0.6 to 20.4. The methodology is a combination of three numerical approaches, i.e. direct numerical simulation of turbulent flow, the point-particle immersed boundary method, and the discrete particle method. By applying the Vorono analysis, the preferential concentration characteristics of sediment particles were investigated quantitatively. It was found that the normalized area of the Voronoi cells follows a lognormal particle distribution. The inertial sediment particles distributed unevenly in the turbulent boundary layer and the unevenness, governed by the particle Stokes number, was more significant as the particle Stokes number approaches unity. The inertial sediment particles in the turbulent boundary layer accumulated preferentially in streamwise-aligned streaky structures and this pattern was less significant with increasing particle Stokes number.

关键词： Inertial sediment particles Turbulent boundary layers Voronoi analysis Direct numerical simulation

mmWave mobile communication under hypercellular architecture

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Journal of Communications and Information Networks 2016年第2期1卷 62-76页

作者： LI Jiahui HUANG Fei ZHOU Runyun CHEN Wenhua TIAN Zhigang ZHOU Shidong Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

To meet the ever growing traffic in mobile communication,mmWave(millimeter-Wave)frequency bands have gained considerable attention for having a greater amount of bandwidth available than the current cellular spectrum below 3 GHz.Several test systems have been reported on recently to validate the possibility of mmWave links in mobile scenarios.However,there still exist practical issues to enable the application of mmWave in mobile communication,including reliability and cost.In this article,we present some new designs that address these issues,where system architecture,transceiver architecture,and related issues such as circuits and antenna arrays are considered.Hypercellular architecture is applied in mmWave mobile networks to overcome blockage problems,and a Butler-matrix-based HBF(Hybrid Beamforming)architecture is considered in an mmWave link.Simulations and experimental results are presented to validate the effectiveness of the Butler-matrix-based system.

关键词： Butler matrix hypercellular architecture hybrid beamforming millimeter wave transceiver architecture