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A Greedy Algorithm for Task Offloading in Mobile Edge Computing System

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China Communications 2018年第11期15卷 149-157页

作者： Feng Wei Sixuan Chen weixia zou Key Lab.of Universal Wireless Communications MOE Beijing University of Posts and Telecommunications State Key Lab.of Millimeter Waves Southeast University

Mobile edge computing （MEC） is a novel technique that can reduce mobiles＇ com- putational burden by tasks offioading, which emerges as a promising paradigm to provide computing capabilities in close proximity to mobile users. In this paper, we will study the scenario where multiple mobiles upload tasks to a MEC server in a sing cell, and allocating the limited server resources and wireless chan- nels between mobiles becomes a challenge. We formulate the optimization problem for the energy saved on mobiles with the tasks being dividable, and utilize a greedy choice to solve the problem. A Select Maximum Saved Energy First （SMSEF） algorithm is proposed to realize the solving process. We examined the saved energy at different number of nodes and channels, and the results show that the proposed scheme can effectively help mobiles to save energy in the MEC system.

关键词： mobile edge computing task off- loading greedy choice energy resource allo- cation

On Multi-Frequency Channel Interference Alignment of 3 Channels and 4 Users

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China Communications 2016年第1期13卷 22-32页

作者： DU Guanglong zou weixia ZHOU Zheng Key Lab of Universal Wireless Communications MOEBeijing University of Posts and Telecommunications State Key Lab.of Millimeter Waves Southeast University

This paper explores the multi-frequency independent channel interference alignment(MFC-IA) system of 3 channels and4 users,and single data stream transmit,i.e.(3×3,1)~4 *** derive the analytic solution for(3×3,1)~4 MFC-IA *** on the analytic solution,an optimization problem is proposed aim at the optimal IA *** based on such a math model,we propose a simulated annealing(SA) algorithm to search optimal IA *** simulation results show that the simulated annealing IA algorithm has a better sum rate performance than iterative maximize signal to interference plus noise ratio(Max-SINR) *** result can be extended to single data stream multi-antenna IA system with 3 antennas and4 users.

关键词： communication and information system interference alignment multi-frequency channel analytic solution simulated annealing

Distance control strategy for deploying content replica servers in an edge cloud

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The Journal of China Universities of Posts and Telecommunications 2019年第2期26卷 91-98页

作者： Wei Feng zou weixia Wang Zhen Wu Xiaomei Key Laboratory of Universal Wireless Communications MOEBeijing University of Posts and TelecommunicationsBeijing 100876China Slate Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China Department of Communication Engineering Dalian Neusoft University of InformationDalian 116023China Department of Product and Infrastructure of CTTL-systems China Academy of Information and Communications TechnologyBeijing 100088China

To reduce fetching cost from a remote source,it is natural to cache information near the users who may access the information ***,with development of 5 G ultra-dense cellular networks andmobile edge computing(MEC),a reasonable selection among edge servers for content delivery becomes a problem when the mobile edge obtaining sufficient replica *** order to minimize the total cost accounting for both caching and fetching process,we study the optimal resource allocation for the content replica servers’ *** decompose the total cost as the superposition of cost in several ***,we consider the criterion for determining the coverage of a replica server and formulate the coverage as a tradeoff between caching cost and fetching *** to the criterion,a coverage isolation(CI) algorithm is proposed to solve the deployment *** numerical results show that the proposed CI algorithm can reduce the cost and obtain a higher tolerance for different centrality indices.

关键词： content delivery network (CDN) MEC replica server deployment minimum cost greedy algorithm

Hybrid Precoder and Combiner Design with Finite Resolution PSs for mmWave MIMO Systems

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China Communications 2019年第2期16卷 95-104页

作者： Ran Zhang weixia zou Ye Wang Mingyang Cui Key Lab of Universal Wireless Communications MOEBeijing University of Posts and Telecommunications State Key Lab.of Millimeter Waves Southeast University

Hybrid precoding and combining have been considered as a promising technology, which can provide a compromise between hardware complexity and system performance in millimeter wave multiple-input multiple-output systems. However, most existing hybrid precoder and combiner designs generally assume that infinite resolution phase shifters(PSs) are used to produce the analog beamformers. In a practical scene, the design with accurate PSs can lead to high hardware cost and power consumption. In this paper, we investigate the hybrid precoder and combiner design with finite resolution PSs in millimeter wave systems. We employ alternate optimization as the main strategy to jointly design analog precoder and combiner. In addition, we propose a low complexity algorithm, where the analog beamformers are implemented only by finite resolution PSs to maximize spectral efficiency. Then, the digital precoder and combiner are designed based on the obtained analog beamformers to improve the spectral efficiency. Finally, simulation results and mathematical analysis show that the proposed algorithm with low-resolution PSs can achieve near-optimal performance and have low complexity.

关键词： millimeter wave multiple-input multiple-output finite resolution phase shifters hybrid precoding alternate optimization

护理循证实践对社区多重用药慢性病患者服药依从性的影响

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现代医院 2024年第9期24卷 1456-1459页

作者：万晓敏邹伟霞李婷东莞市南城社区卫生服务中心广东东莞523411

目的探讨循证护理对社区多重用药慢性病患者服药依从性的影响作用。方法选取2023年1—6月已纳入管理的60例多重用药的慢性病患者,按应用循证护理前后分为对照组与观察组,每组各30例。对照组采用常规护理方案,观察组采用循证护理方案,比... 详细信息

目的探讨循证护理对社区多重用药慢性病患者服药依从性的影响作用。方法选取2023年1—6月已纳入管理的60例多重用药的慢性病患者,按应用循证护理前后分为对照组与观察组,每组各30例。对照组采用常规护理方案,观察组采用循证护理方案,比较证据应用前后审查指标执行率、两组患者的服药依从性、药物持有率及社区护士慢性病药物知识水平。结果证据应用后审查指标执行率更高,观察组患者服药依从性及药物持有率均高于对照组,证据应用后社区护士慢性病药物知识水平明显提高,差异均有统计学意义(P<0.05)。结论循证护理实践可规范社区慢性病多重用药患者服药依从性管理,改善多重用药慢性病患者的服药依从性,提高社区护士慢性病药物知识水平。

关键词：循证护理服药依从性多重用药慢性病管理社区

A New Codebook Design Scheme for Fast Beam Searching in Millimeter-Wave Communications

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China Communications 2014年第6期11卷 12-22页

作者： zou weixia GUO Chao DU Guanglong WANG Zhenyu GAO Ying Key Lab of Universal Wireless Communications School of Information and Communication Engineering Beijing University of Posts and Telecommunications (BUPT) School of Electronic Engineering Beijing University of Posts and Telecommunications (BUPT)

To overcome imperfection of exhaustive based beam searching scheme in IEEE 802.15.3c and IEEE 802.11 ad and accelerate the beam training process, combined with the fast beam searching algorithm previously proposed, this paper proposed a beam codebook design scheme for phased array to not only satisfy the fast beam searching algorithm's demand, but also make good use of the advantage of the searching algorithm. The simulation results prove that the proposed scheme not only performs well on flexibility and searching time complexity, but also has high success ratio.

关键词： wireless communication 60GHz phased array beam-forming beam searching beam codebook design

Prior information based channel estimation for millimeter-wave massive MIMO vehicular communications in 5G and beyond

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Frontiers of Information Technology & Electronic Engineering 2021年第6期22卷 777-789页

作者： Zhao YI weixia zou Xuebin SUN MOE Key Laboratory of Universal Wireless Communications Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China

Millimeter wave(mm Wave) has been claimed as the viable solution for high-bandwidth vehicular communications in 5 G and beyond. To realize applications in future vehicular communications, it is important to take a robust mm Wave vehicular network into consideration. However, one challenge in such a network is that mm Wave should provide an ultra-fast and high-rate data exchange among vehicles or vehicle-to-infrastructure(V2 I). Moreover,traditional real-time channel estimation strategies are unavailable because vehicle mobility leads to a fast variation mm Wave channel. To overcome these issues, a channel estimation approach for mm Wave V2 I communications is proposed in this paper. Specifically, by considering a fast-moving vehicle secnario, a corresponding mathematical model for a fast time-varying channel is first established. Then, the temporal variation rule between the base station and each mobile user and the determined direction-of-arrival are used to predict the time-varying channel prior information(PI). Finally, by exploiting the PI and the characteristics of the channel, the time-varying channel is estimated. The simulation results show that the scheme in this paper outperforms traditional ones in both normalized mean square error and sum-rate performance in the mm Wave time-varying vehicular system.

关键词： Massive multiple-input multiple-output Millimeter wave Channel estimation Vehicular communication Time-varying

An adaptive channel estimation algorithm for millimeter wave cellular systems

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Journal of Communications and Information Networks 2016年第2期1卷 37-44页

作者： LU Wenlü zou weixia LIU Xuefeng Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing 100876China State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China

The large bandwidth available with mmWave(millimeter Wave)makes it a promising candidate for 5th generation cellular *** channel estimation algorithms must be developed to enable beamforming in mmWave *** this paper,we propose an adaptive channel estimation algorithm that exploits the poor scattering nature of the mmWave channel and adjusts the training overhead adaptively with the change of channel quality for mmWave cellular ***,we use a short training sequence to estimate the channel parameters based on the two-dimensional discrete Fourier transform ***,we design a feedback scheme to adjust the length of the training sequence under the premise of ensuring the accuracy of the channel *** key threshold in the feedback scheme is derived and its influence on the accuracy of the estimation results is *** results confirm that the proposed algorithm can adjust the length of the training sequence adaptively according to the current channel condition maintaining a stable estimation accuracy.

关键词： millimeter wave 5G cellular system large antenna array adaptive channel estimation

A novel adaptive spectrum forming filter:Application in cognitive ultra-wideband

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Science China(Information Sciences) 2010年第12期53卷 2584-2599页

作者： LI Bin ,ZHOU Zheng & zou weixia Key Lab of Universal Wireless Communications,MOE.Wireless Network Lab,Beijing University of Posts and Telecommunications,Beijing 100876,China Key Lab of Universal Wireless Communications MOE. Wireless Network Lab Beijing University of Posts and Telecommunications Beijing China

Ultra wideband impulse radio(UWB-IR) has important applications in high data rate communications,high precision positioning and penetrating target *** with cognitive radio(CR),UWB can also greatly alleviate the current spectrum ***,the existing UWB waveforms are faced with two *** spectrum utilization of UWB signal is rather low,which reduces the communication ***,it appears difficult for UWB-IR to avoid spectrum collision with other incumbent *** UWB will inevitably interfere other legal wireless *** by these considerations,we model the UWB waveform design into an interpolation *** on radial basis function neural network,a novel UWB pulse is presented in this *** UWB pulse is then realized though reasonable simplification on the already proposed theoretical *** designed UWB pulses can adaptively track the external spectral environment where UWB devices work and reconfigure its emission spectrum according to the state of primer users without any modification on *** frequency utilization is maximized when there is no active primary *** adequate spectrum avoidance has also been achieved without much spectrum utilization degradation within the non-primary *** and analysis show that our UWB-IR pulse is much superior to the other existing UWB signals in the frequency utilization,spectrum avoidance and in the transmission performance.

关键词： UWB-IR cognitive radio pulse design RBF network spectrum efficiency spectrum avoidance