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Full-spectrum cell-free RAN for 6G systems: system design and experimental results

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Science China(Information Sciences) 2023年第3期66卷 80-93页

作者： Dongming WANG Xiaohu YOU Yongming HUANG Wei XU Jiamin LI Pengcheng ZHU Yanxiang JIANG Yang CAO Xinjiang XIA Ziyang ZHANG Qingji JIANG Pan WANG Dongjie LIU Kang ZHENG Mengting LOU Jing JIN Qixing WANG Jiangzhou WANG National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories China Mobile research Institute School of Engineering University of Kent

With distributed transceivers and scalable cooperative transmission, cell-free massive multipleinput multiple-output(CF-m MIMO) technology eliminates the “cells” of traditional mobile communications,thereby significantly improving the performance of wireless networks. CF-m MIMO is considered as a major technical tool for achieving the key performance indicators of sixth generation(6G) mobile communication systems. In this paper, a scalable implementation architecture for CF-m MIMO is proposed, based on which potential key technologies such as channel information acquisition, transceiver design, dynamic user and access point association, and novel duplexing are introduced. Finally, based on low-cost commercial access points, a CF-m MIMO testbed with 64 transmit and receive antennas is developed, and the performance of the distributed receiver design is evaluated.

关键词： 6G scalable cell-free massive MIMO cell-free radio access network prototype system

An iterative BiGAMP-based receiver for coded massive MIMO systems with low-resolution ADCs

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Science China(Information Sciences) 2021年第11期64卷 247-248页

作者： Yi SUN Ming JIANG Chunming ZHAO National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories

Dear editor,The hundreds of antennas deployed in massive multipleinput-multiple-output(MIMO) systems lead to an insupportable burden in terms of hardware costs and power consumption. This has motivated the research on... 详细信息

关键词： Information Systems and Communication Service

Microstructure and mechanical properties of CoCrFeMnNi high entropy alloy with ultrasonic nanocrystal surface modification process

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Journal of Materials Science & technology 2020年第22期54卷 123-130页

作者： Timothy Alexander Listyawan Hyunjong Lee Nokeun Park Unhae Lee School of Materials Science and Engineering Yeungnam University280 Daehak-roCyeongsanGyeongsangbuk-do 38541Republic of Korea advanced Process and Materials R&D Group Korea Institute of Industrial TechnologyIncheon 21999Republic of Korea Institute of Materials technology Yeungnam University280 Daehak-roGyeongsanGyeongsangbuk-do 38541Republic of Korea POSCO Technical research laboratories Gwangyang 57807Republic of Korea

In this study, mechanical properties improvement of equiatomic CoCrFeMnNi treated with an ultrasonic nanocrystal surface modification(UNSM) was studied. The applied UNSM treatment with static loads of 10 N, 20 N, and 60 N provided a severe plastic deformation, which produced a gradient structure. The nearsurface area exhibited a high number of dislocation densities and deformation twin interaction, leading to a surface strengthening and hardness improvement of up to 112% than the deformation-free interior region. Increment of dislocation densities and deformation twin formation on the surface also enhanced the yield and ultimate tensile strength of the UNSM-treated specimens. Furthermore, the combination of hard nanocrystallites layer on the surface and ductile coarse grain in the specimen interior as a result of the UNSM treatment successfully maintained the strength–ductility balance of the CoCrFeMnNi.

关键词： High-entropy alloy Ultrasonic nanocrystal surface modification Severe plastic deformation Microstructures Mechanical properties

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Bayesian optimization with experimental failure for high-throughput materials growth

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npj Computational Materials 2022年第1期8卷 1746-1754页

作者： Yuki K.Wakabayashi Takuma Otsuka Yoshiharu Krockenberger Hiroshi Sawada Yoshitaka Taniyasu Hideki Yamamoto NTT Basic research laboratories NTT CorporationAtsugiKanagawa243-0198Japan NTT Communication Science laboratories NTT CorporationSoraku-gunKyoto619-0237Japan

A crucial problem in achieving innovative high-throughput materials growth with machine learning,such as Bayesian optimization(BO),and automation techniques has been a lack of an appropriate way to handle missing data due to experimental ***,we propose a BO algorithm that complements the missing data in optimizing materials growth *** proposed method provides a flexible optimization algorithm that searches a wide multi-dimensional parameter *** demonstrate the effectiveness of the method with simulated data as well as in its implementation for actual materials growth,namely machine-learning-assisted molecular beam epitaxy(ML-MBE)of SrRuO_(3),which is widely used as a metallic electrode in oxide *** the exploitation and exploration in a wide three-dimensional parameter space,while complementing the missing data,we attained tensile-strained SrRuO3 film with a high residual resistivity ratio of 80.1,the highest among tensile-strained SrRuO3 films ever reported,in only 35 MBE growth runs.

关键词： optimization strained resistivity

6G extreme connectivity via exploring spatiotemporal exchangeability

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Science China(Information Sciences) 2023年第3期66卷 94-96页

作者： Xiaohu YOU National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories

MIMO channel capacity collapse effect. The blocklength of channel coding is a critical factor that affects the communication latency over wireless channels. In the fifth-generation(5G) wireless communication network, a new structure of mini-slot has been introduced to support the requirement of communication latency no larger than 1 ms. Towards the next-generation wireless communication network, i.e.,

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A New Pseudo Sesquiterpenoid from the Seeds of Koelreuteria paniculata

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Chinese Chemical Letters 2002年第11期13卷 1067-1068页

作者： Wen Han LIN Hai Ming LEI Hong Zheng FU Jun LI National research laboratories of Natural and Biomimetic Drugs Peking UniversityBeijing 100083

From the seeds of medicinal plant Koelreuteria paniculata, a new pseudo sesquiter- penoid with novel skeleton namely paniculoid 1 was isolated. The structure of 1 was established on the basis of extensive 2D NMR spec... 详细信息

关键词： Koelreuteria Paniculata seeds paniculoid structural elucidation.

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An ensemble and cost-sensitive learning-based root cause diagnosis scheme for wireless networks with spatially imbalanced user data distribution

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Science China(Information Sciences) 2024年第7期67卷 331-332页

作者： Qi WANG Zhiwen PAN Nan LIU National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories

Root cause diagnosis, a key component of self-healing, plays a vital role in fault management. The spatially imbalanced network key performance indicators (KPIs) reported by users increase the difficulty of identifying root *** [1,2], the image inpainting technique is inspired to address issues caused by sparse reports across the coverage area.

关键词： Wireless networks

Growth and low-energy electron microscopy characteri- zation of monolayer hexagonal boron nitride on epitaxial cobalt

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Nano research 2013年第5期6卷 335-347页

作者： Carlo M. Orofeo Satoru Suzuki Hiroyuki Kageshima Hiroki Hibino NTT Basic research laboratories NTT Corporation A tsugi Kanagawa 243-0198 Japan

Low-energy electron microscopy （LEEM） has been used to study the structure, initial growth orientation, growth progression, and the number of layers of atomically thin hexagonal boron nitride （h-BN） films. The h-BN films are grown on heteroepitaxial Co using chemical vapor deposition （CVD） at low pressure. Our findings from LEEM studies include the growth of monolayer film having two, oppositely oriented, triangular BN domains commensurate with the Co lattice. The growth of h-BN appears to be self-limiting at a monolayer, with thicker domains only appearing in patches, presumably initiated between domain boundaries. Reflectivity measurements of the thicker h-BN films show oscillations resulting from the resonant electron transmission through quantized electronic states of the h-BN films, with the number of minima scaling up with the number of h-BN layers. First principles density functional theory （DFT） calculations show that the positions of oscillations are related to the electronic band structure of h-BN.

关键词： chemical vapor deposition cobalt domain boundaries hexagonal boron nitride low-energy electronmicroscopy (LEEM)

Effect of coating material and lubricant on forming force and surface defects in wire drawing process

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 104-110页

作者： S.M.BYON S.J.LEE D.W.LEE Y.H.LEE Y.LEE Department of Mechanical Engineering Dong-A University Department of Mechanical Engineering Chung-Ang University Wire Rod research Group POSCO Technical Research Laboratories

A pilot wire drawing machine as well as wire end-pointing roller was developed. Using these machines, a wire drawing test for four different coating materials and two different lubricants was performed as the reduction ratio increased from 10% to 30%. Materials used for a substrate in this study are plain carbon steel （AIS11045） and ultra low carbon bainite steel. To compute the friction coefficient between the coating layer of wire and the surface of die lbr a specific lubricant, a series of finite element analyses were carried out. SEM observations were also conducted to investigate the surface defects of wire deformed. Results show that the behavior of drawing force varies with the lubricant-type at the initial stage of drawing. The powder-typed lubricant with a large particle causes the retardation of lull lubrication on the entire contact surface and the local delamination of coating layer on the wire surface. As the flow stress of a substrate increases, the delamination becomes severe.

关键词： coating lubricant wire drawing delamination

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