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Static CSI Extraction and Application in the Tomographic Channel Model

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China Communications 2019年第12期16卷 132-144页

作者： Haihan Li Yunzhou Li shidong zhou Jing Wang Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

In this paper, the statistical properties of parameters of each path in wireless channel models are analyzed to prove that there is the static part in channel state information(CSI) which can be extracted from huge amounts of CSI data. Based on the analysis, the concept of the Tomographic Channel Model(TCM) is presented. With cluster algorithms, the static CSI database can be built in an off-line manner. The static CSI database can provide prior information to help pilot design to reduce overhead and improve accuracy in channel estimation. A new CSI prediction method and a new channel estimation method between different frequency bands are introduced based on the static CSI database. Using measurement data, the performance of the new channel prediction method is compared with that of the Auto Regression(AR) predictor. The results indicate that the prediction range of the new method is better than that of the AR method and the new method can predict with fewer pilot symbols. Using measurement data, the new channel estimation method between different frequency bands can estimate the CSI of one frequency band based on known CSI of another frequency band without any feedback.

关键词： big data tomographic channel model channel prediction channel estimation channel feedback K-means clustering

Pilot Domain NOMA for Grant-Free Massive Random Access in Massive MIMO Marine Communication System

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China Communications 2020年第6期17卷 131-144页

作者： Yongxin Liu Ming Zhao Limin Xiao shidong zhou Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Tsinghua National Laboratory for Information Science and Technology Tsinghua UniversityBeijing 100084China

We propose a pilot domain non-orthogonal multiple access(NOMA)for uplink massive devices grant-free random access scenarios in massive multiple-input multiple-output(MIMO)maritime communication systems.These scenarios are characterized by numerous devices with sporadic access behavior,and therefore only a subset of them are active.Due to massive potential devices in the network,it is infeasible to assign a unique orthogonal pilot to each device in advance.In such scenarios,pilot decontamination is a crucial problem.In this paper,the devices are randomly assigned non-orthogonal pilots which are constructed by a linear combination of some orthogonal pilots.We show that a bipartite graph can conveniently describe the interference cancellation(IC)processes of pilot decontamination.High spectrum efficiency(SE)and low outage probability can be obtained by selecting the numbers of orthogonal pilots according to the given probability distribution.Numerical evaluatioDs show that the proposed pilot domain NOMA decreases the outage probability from 20%to 2 e-12 at the SE of 4 bits/s/Hz for a single device,compared to the conventional method of slotted ALOHA with 1024 antennas at the BS,or increases the spectrum efficiency from 1.2 bits/s/Hz to 4 bit/s/Hz at the outage probability of2 e-12 in contrast with the Welch bound equality(WBE)non-orthogonal pilots.

关键词： NOMA grant-free random access maritime-communication bipartite graphs density evolution

Convolutional Neural Networks Based Indoor Wi-Fi Localization with a Novel Kind of CSI Images

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China Communications 2019年第9期16卷 250-260页

作者： Haihan Li Xiangsheng Zeng Yunzhou Li shidong zhou Jing Wang Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

Indoor Wi-Fi localization of mobile devices plays a more and more important role along with the rapid growth of location-based services and Wi-Fi mobile devices.In this paper,a new method of constructing the channel state information(CSI)image is proposed to improve the localization accuracy.Compared with previous methods of constructing the CSI image,the new kind of CSI image proposed is able to contain more channel information such as the angle of arrival(AoA),the time of arrival(TOA)and the amplitude.We construct three gray images by using phase differences of different antennas and amplitudes of different subcarriers of one antenna,and then merge them to form one RGB image.The localization method has off-line stage and on-line stage.In the off-line stage,the composed three-channel RGB images at training locations are used to train a convolutional neural network(CNN)which has been proved to be efficient in image recognition.In the on-line stage,images at test locations are fed to the well-trained CNN model and the localization result is the weighted mean value with highest output values.The performance of the proposed method is verified with extensive experiments in the representative indoor environment.

关键词： convolutional neural network indoor Wi-Fi localization channel state information CSI image

Optimal cooperative energy spectrum sensing in cognitive radio network

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Frontiers of Electrical and Electronic Engineering in China 2010年第4期5卷 449-455页

作者： Haijun WANG Xin SU Yi XU shidong zhou Jing WANG Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

Cooperative energy spectrum sensing has been proved effective to detect the spectrum holes in cognitive radio(CR).In this paper,we present the optimal energy sensing algorithm in CR network and prove its optimality through the duality theorem of Neyman-Pearson theorem.Then,the optimal energy sensing algorithm is expanded to a cooperative sensing algorithm based on channel covariance matrix.We compare the proposed algorithms with traditional cooperative sensing algorithms in terms of complexity and required transmission bits.Simulation results validate the optimality of the proposed cooperative sensing algorithm.Furthermore,it is intuitively reasonable for the sensing station to choose the sensing nodes with better channel condition to cooperate,which is verified by our analysis and simulation.

关键词： cognitive radio(CR) cooperative sensing likelihood-ratio test

Wireless channel feature extraction via GMM and CNN in the tomographic channel model

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Journal of Communications and Information Networks 2017年第1期2卷 41-51页

作者： Haihan Li Yunzhou Li shidong zhou Jing Wang Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Tsinghua National Laboratory for Information Science and Technology Tsinghua UniversityBeijing 100084China

Wireless channel modeling has always been one of the most fundamental highlights of the wireless communication research.The performance of new advanced models and technologies heavily depends on the accuracy of the wireless CSI(Channel State Information).This study examined the randomness of the wireless channel parameters based on the characteristics of the radio propagation environment.The diversity of the statistical properties of wireless channel parameters inspired us to introduce the concept of the tomographic channel model.With this model,the static part of the CSI can be extracted from the huge amount of existing CSI data of previous measurements,which can be de ned as the wireless channel feature.In the proposed scheme for obtaining CSI with the tomographic channel model,the GMM(Gaussian Mixture Model)is applied to acquire the distribution of the wireless channel parameters,and the CNN(Convolutional Neural Network)is applied to automatically distinguish di erent wireless channels.The wireless channel feature information can be stored oine to guide the design of pilot symbols and save pilot resources.The numerical results based on actual measurements demonstrated the clear diversity of the statistical properties of wireless channel parameters and that the proposed scheme can extract the wireless channel feature automatically with fewer pilot resources.Thus,computing and storage resources can be exchanged for the nite and precious spectrum resource.

关键词： wireless channel modeling tomographic channel model Gaussian mixture model convolutional neural network

Surfactant Surface Tension Effects on Promoting Hydrate Formation: An Experimental Study Using Fluorocarbon Surfactant (Intechem-01) + SDS Composite Surfactant

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Journal of Environmental Protection 2013年第5期4卷 42-48页

作者： Lin Zhang shidong zhou Shuli Wang Lei Wang Jianmin Li China Jiangsu Key Laboratory of Oil & Gas Storage and Transportation Technology School of Petroleum Engineering Changzhou University Changzhou China

The investigation of surface tension is a very important task for gas hydrate studying. Surfactants can effectively reduce the surface tension, improve the gas storage capability of hydrate and increase the formation rate, shorten the induction time. The objective of this study were to obtain a better understanding of the role of surface tension on hydrate formation and build gas hydrate models involve surfactant. In this study it was highlighted that the surface tension of Intechem-01 + SDS composite surfactants in natural gas hydrate promotion system and the change rules at different temperatures, concentration and proportion. According to the results of experiment, the surface tension of composite surfactants decreased with the increase of Intechem-01. The best cooperating effect was observed in proportion (Intechem-01 content) of 0.6 - 0.7, where the surface tension was the lowest. In this proportion range, the composite surfactants showed the same effect to pure fluorine carbon surfactant. The study shown the surface tension of composite surfactants decreased with the rise of temperature, and they were in a linear relationship within a certain range. Surface tension of composite surfactants decreased with the increase of surfactant concentration, however, it was no longer decreased above critical micelle concentration (CMC). The fitting equation of surface tension with various factors has been obtained.

关键词： Natural Gas Hydrate Hydrate Promoter Surfactant Surface Tension Fitting Equation

什邡雪茄烟叶黑胫病菌遗传多样性分析及防治药剂筛选

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中国烟草科学 2024年第1期45卷 79-86页

作者：王瑢笙毕馨月王俊向欢兰鑫宇周士栋吴元华陈勇沈阳农业大学植物保护学院沈阳110866 四川省烟草公司德阳市公司四川德阳618400

为有效防控什邡地区雪茄烟叶黑胫病,对什邡地区27株烟草黑胫病菌(Phytophthora parasitica)进行交配型测定、SSR遗传多样性分析和6种常用药剂的室内筛选。结果表明,什邡地区菌株均为A2交配型,以无性生殖为主;病原菌群体Simpson(λ)指数... 详细信息

为有效防控什邡地区雪茄烟叶黑胫病,对什邡地区27株烟草黑胫病菌(Phytophthora parasitica)进行交配型测定、SSR遗传多样性分析和6种常用药剂的室内筛选。结果表明,什邡地区菌株均为A2交配型,以无性生殖为主;病原菌群体Simpson(λ)指数和均匀度指数(E._(5))分别为0.776和0.643,说明该地区菌株具有较高水平的遗传多样性;分子方差分析与主坐标分析显示什邡地区烟草黑胫病菌群体与云南、贵州、四川其他地区和重庆的菌株具有一定的差异,群体92%变异来源于内部;甲霜灵、烯酰吗啉和烯酰氰霜唑对该地区黑胫病菌株具有较好的抑菌效果,平均EC_(50)值分别为0.491、0.574和0.730 mg/L。研究结果可为什邡地区雪茄烟叶黑胫病的科学、有效防治提供依据。

关键词：雪茄烟叶黑胫病交配型遗传多样性药剂筛选

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制氢与储氢技术课程建设

创新创业理论研究与实践 2024年第9期7卷 34-38页

作者：李孝艳李恩田周昊周诗岽柳扬吕晓方常州大学石油与天然气工程学院能源学院

在“双碳”背景下，氢能作为一种燃烧热值高、零碳排放的优质可再生能源，逐渐受到重视。我国早期氢能发展主要集中在氢能利用的下游环节（氢燃料电池），高校的相关课程也主要与燃料电池相关。最近，我国不断布局氢能上游制氢与中游储... 详细信息

在“双碳”背景下，氢能作为一种燃烧热值高、零碳排放的优质可再生能源，逐渐受到重视。我国早期氢能发展主要集中在氢能利用的下游环节（氢燃料电池），高校的相关课程也主要与燃料电池相关。最近，我国不断布局氢能上游制氢与中游储氢产业，制氢与储氢相关产业得到了快速发展，亟需大量具有相关背景的专业人才。该文通过对制氢与储氢技术课程建设进行探讨，初步明确了制氢与储氢课程的教学内容及目标；随后，基于该课程的特点制定了相应的教学方法；最后，提出了该课程的考核评价方式。该课程的建设对于培养具有氢能制—储—运—用全产业链背景的专业人才具有重要意义。

关键词：氢能制氢储氢课程建设教学内容教学方法

含蜡及表面活性剂环戊烷水合物浆液生成及黏度特性

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低碳化学与化工 2024年第4期49卷 113-123页

作者：柳扬陈杰李娜孟嘉伟吕晓方周诗岽马千里王传硕常州大学石油与天然气工程学院能源学院江苏常州213164 中国石油技术开发公司北京100028 中国石油天然气股份有限公司华北油田分公司河北沧州062552

随着油气资源开采不断向深水领域发展,在深水管道多相混输过程中,低温高压的输送环境极易导致水合物和蜡等固相沉积堵塞管道的问题产生,尤其当蜡和水合物同时存在时,集输管道将面临更高的堵管风险。为此,使用流变仪研究了含蜡和表面活性... 详细信息

随着油气资源开采不断向深水领域发展,在深水管道多相混输过程中,低温高压的输送环境极易导致水合物和蜡等固相沉积堵塞管道的问题产生,尤其当蜡和水合物同时存在时,集输管道将面临更高的堵管风险。为此,使用流变仪研究了含蜡和表面活性剂(Span 80)的油水体系中环戊烷水合物的生成规律及水合物浆液流变性,明确了含蜡量(质量分数,下同)、Span 80浓度(质量分数,下同)等因素对蜡-水合物共存体系临界时间及浆液剪切稀释性的影响规律。结果表明,Span 80浓度为1.0%时,含蜡量由0.00%增大至1.00%,水合物生成临界时间由25.8 min延长至49.8 min,增幅约93%。在Span 80浓度为1.5%、2.0%及3.0%时,水合物生成临界时间同样随含蜡量增大而延长,增幅分别为113%、93%及241%。对中低含蜡量体系(≤0.75%),水合物生成临界时间随Span 80浓度的增大而缩短;对高含蜡量体系(≥1.00%),水合物生成临界时间则随着Span 80浓度的增大呈现波动变化。此外,随着水合物的生成,含蜡与不含蜡体系水合物浆液的黏度均先快速增大再逐渐减小并趋于稳定,含蜡体系水合物浆液的黏度峰值与最终平衡黏度均显著大于不含蜡体系的对应值。通过比较稠度系数和流动特性指数,发现含蜡体系水合物浆液的流动特性指数随着含蜡量、Span 80浓度的增大而增大,含蜡油水乳状液、水合物浆液及含蜡水合物浆液均具有剪切稀释性,含蜡水合物浆液则具有更强的剪切稀释性。

关键词：蜡晶表面活性剂水合物浆液临界时间剪切稀释性