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Frequency domain decision feedback equalizer for time-reversal space-time block coding

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The Journal of China Universities of Posts and Telecommunications 2012年第1期19卷 38-43页

作者： DONG Chao LIN Jia-ru NIU Kai he zhi-qiang BIE zhi-song The Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

In this paper, a frequency domain decision feedback equalizer is proposed for single carrier transmission with time-reversal space-time block coding （TR-STBC）. It is shown that the diagonal decision feedback equalizer matrix can be calculated from the frequency domain channel response. Under the perfect feedback assumption, the proposed equalizer can approach matched filter bound （MFB）. Compared with the existing time domain decision feedback equalizer, the proposed equalizer exhibits better performance with the same equalization complexity.

关键词： decision feedback equalization matched filter bound time-reversal space-time block coding （TR-STBC）

Interaction Effects of Gene Polymorphisms and Obesity on Nonalcoholic Fatty Liver Disease

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Biomedical and Environmental Sciences 2019年第10期32卷 793-796页

作者： SUN Xiao Ya he zhi qiang WANG Li Qun WANG zhi Zhong BAI Fei Hu YOU Yan Jie Department of Epidemiology and Statistic School of Public Health and ManagementNingxia Medical UniversityYinchuan 750004NingxiaChina Department of gastroenterology at Ningxia Hui Autonomous Region People's Hospital Yinchuan 750021NingxiaChina

Nonalcoholic fatty liver disease(NAFLD)is a common chronic condition that affects adults and has a global prevalence of 25%[1],with the prevalence being 31%among the general population in China[2].A meta-analysis of studies conducted over the past few years has reported that the predicting factors for NAFLD include obesity,type 2 diabetes mellitus,lifestyle,and genetic variants.The risk of developing NAFLD has been reported to be 3.5-fold higher in individuals with obesity than in the general[3].

关键词： NAFLD obesity prevalence

Phase noise correction for OFDM signal based on DCT approach and variational inference

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The Journal of China Universities of Posts and Telecommunications 2012年第3期19卷 27-32页

作者： CheN Peng LI Nan LI Ju-hu he zhi-qiang WU Wei-ling Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

A novel scheme to joint phase noise （PHN） correcting and channel noise variance estimating for orthogonal frequency division multiplexing （OFDM） signal was proposed, The new scheme was based on the variational Bayes （VB） method and discrete cosine transform （DCT） approximation. Compared with the least squares （LS） based scheme, the proposed scheme could overcome the over-fitting phenomenon and thus lead to an improved performance. Computer simulations showed that the proposed VB based scheme outperforms the existing LS based scheme

关键词： variational Bayes method discrete cosine transform phase noise OFDM

Optimal energy-efficiency capacity and sensing tradeoff for hybrid spectrum sharing in CRN

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The Journal of China Universities of Posts and Telecommunications 2012年第2期19卷 1-8页

作者： QIU Tao XU Wen-jun SONG Tae he zhi-qiang TIAN Bao-yu School of Information and Communications Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China

This paper investigates the tradeoff between energy-efficiency capacity and spectrum sensing under hybrid spectrum sharing model, where the spectrum sharing method is based on sensing results of secondary user （SU）. The metric ＇bits per joule＇, which captures the effect of energy overhead in spectrum sensing, is adopted to evaluate energy-efficiency capacity. We first formulize the tradeoff between energy-efficiency capacity and spectrum sensing as an optimization problem with mixture constraint of sensing time and detection threshold. Under some certain condition on the domain of detection threshold, i.e. in which we can＇t improve energy-efficiency capacity through increasing the detection probability, the original optimization problem can be reduced to a new unconstrained one, which only relates to sensing time. Then the existence and uniqueness of optimal sensing time to achieve maximum energy-efficiency capacity are discussed and a low-complexity algorithm is proposed to obtain the optimal solution. Finally, numerical simulation is performed to verify the theoretical analysis results. The simulation results indicate that hybrid spectrum sharing is remarkably beneficial to energy-efficient transmission in cognitive radio networks （CRN）. And the proposed algorithm can quickly converge to the optimal solution.

关键词： energy-efficiency capacity spectrum sensing hybrid spectrum sharing cognitive radio network （CRN）

Achievable rate region for the multiple-access channel with multiple cognitive transmitters

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The Journal of China Universities of Posts and Telecommunications 2013年第3期20卷 20-25,24-25页

作者： GUO Yu-chen NIU Kai XU Wen-jun he zhi-qiang LIN Jia-ru Key Lab of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications

A scenario where one ＇dumb＇ radio and multiple cognitive radios communicating simultaneously with a common receiver is considered. In this paper, we derive an achievable rate region of the multiple-user cognitive multiple-access channel （MUCMAC） under both additive white Gaussian noise （AWGN） channel and rayleigh fading channel, by using a combination of multiple user dirty paper coding （DPC） and superposition coding. Through cognition, it is assumed that the secondary users （SUs） are able to obtain the message of the primary user （PU） non-causally beforehand. Using this side information, the SUs can perform multiple user DPC to avoid the interference from the SU. Besides, the SUs can also allocate part of their transmit power to aid the PU, using superposition coding. Therefore, the capacity region of traditional multiple-access channel （MAC） can be enlarged. Moreover, some asymptotic results are shown as the number of SUs increases. In the AWGN case, it is illustrated that the maximum achievable rate of the PU grows logarithmically with the increase of the number of SUs, whereas in the Rayleigh case, we show that the cognitive gain will increase with the decreasing of the channel signal to noise ratio （SNR）.

关键词： cognitive radios MAC superposition coding DPC

Coverage and capacity optimization in LTE network based on non-cooperative games

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The Journal of China Universities of Posts and Telecommunications 2012年第4期19卷 14-21,42页

作者： XU Sen HOU Meng NIU Kai he zhi-qiang WU Wei-ling School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China School of Electronic Engineering and Automation Shandong Polytechnic University Jinan 250353 China

expenditures and operational expenditures （OPEX）（CAPEX） for operator, the coverage and capacity optimization （CCO） is one of the key use cases in long term evolution （LTE） self-organization network （SON）. In LTE system, some factors （e.g. load, traffic type, user distribution, uplink power setting, inter-cell interference, etc.） limit the coverage and capacity performance. From the view of single cell, it always pursuits maximize performance of coverage and capacity by optimizing the uplink power setting and intra-cell resource allocation, but it may result in decreasing the performance of its neighbor cells. Therefore, the benefit of every cell conflicts each other. In order to tradeoff the benefit of every cell and maximize the performance of the whole network, this paper proposes a multi-cell uplink power allocation scheme based on non-cooperative games. The scheme aims to make the performance of coverage and capacity balanced by the negotiation of the uplink power parameters among multi-cells. So the performance of every cell can reach the Nash equilibrium, making it feasible to reduce the inter-cell interference by setting an appropriate uplink power parameter. Finally, the simulation result shows the proposed algorithm can effectively enhance the performance of coverage and capacity in LTE network.

关键词： coverage and capacity power control non-cooperative game Nash equilibrium

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某微型导弹气动特性工程估算与数值仿真研究

计算机仿真 2024年第6期41卷 89-92,97页

作者：张建何志强赵奂强田宏亮中国空空导弹研究院河南洛阳471009

微型化是空空导弹发展的一个重要方向,美国在导弹微型化方面已经取得一些进展。气动特性研究对微型导弹的控制系统和弹道设计具有重要意义,利用工程和数值方法对某微型导弹气动力系数进行仿真,以风洞实验数据为基准对仿真结果的相对误... 详细信息

微型化是空空导弹发展的一个重要方向,美国在导弹微型化方面已经取得一些进展。气动特性研究对微型导弹的控制系统和弹道设计具有重要意义,利用工程和数值方法对某微型导弹气动力系数进行仿真,以风洞实验数据为基准对仿真结果的相对误差进行分析。结果表明,两种仿真方法都能够得到与风洞实验相符的结果,其中数值仿真精度相对误差最大为12.42%,相较于工程方法(相对误差不大于27.31%)精度更高,但是在微型导弹初始方案设计阶段,工程方法计算效率更高。

关键词：微型导弹气动特性工程估算数值仿真

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航空发动机地面进气加温试验

航空发动机 2024年第3期50卷 148-153页

作者：刘作宏何志强柳国印刘佳鑫康忱程鲁中国航发沈阳发动机研究所沈阳110015

为了模拟发动机进气加温试验,开展了发动机地面试车台进气加温试验研究,设计了一套合理的进气加温设备,并提出了进气加温试验测试方案和试验方法。结果表明:在108.88℃进气温度下,高温区角度为180°,高温区主要分布在0°和180°位置,低... 详细信息

为了模拟发动机进气加温试验,开展了发动机地面试车台进气加温试验研究,设计了一套合理的进气加温设备,并提出了进气加温试验测试方案和试验方法。结果表明:在108.88℃进气温度下,高温区角度为180°,高温区主要分布在0°和180°位置,低温区分布在90°和270°位置,隔开了连续高温区,高温区平均温度和面平均温度差值较小,温度周向不均匀度为0.43%,温度分布均匀,不存在强烈温度畸变情况;在进气温度从94.82℃上升至108.88℃时用时80 s,高温区温升率为0.18℃/s,时间域内的温度畸变较小,裕度损失小,温场无旋转,高温区分布和周向温度不均匀度均不随时间变化产生明显改变;在进气温度从65.34℃升至108.88℃时,周向分布保持均匀,建立了面平均温度、高温区面平均温度的线性关系。获得了台架温场均值与发动机控制系统采集进气温度的关系。

关键词：进气加温地面试验温场温度畸变航空发动机

Iron–doped bismuth oxybromides as visible-light-responsive Fenton catalysts for the degradation of atrazine in aqueous phases

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Journal of Environmental Sciences 2024年第3期137卷 321-332页

作者： Yong-Li Cai Yu-Hang Xu Ji-Zun Xiang zhi-qiang Zhang Qiu-Xiang he Ya-Feng Li Jian Lü Fujian Provincial Key Laboratory of Soil Environmental health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China State Key Laboratory of Photocatalysis on Energy and Environment Fuzhou UniversityFuzhou 350116China

Pesticides and its degradation products,being well–known residues in soil,have recently been detected in many water bodies as pollutants of emerging concerns,and thus there is a contemporary demand to develop viable and cost–effective techniques for the removal of related organic pollutants in aqueous phases.herein,a visible-light-responsive Fenton system was constructed with iron–doped bismuth oxybromides(Fe–BiOBr)as the catalysts.Taking the advantage of sustainable Fe(Ⅲ)/Fe(Ⅱ)conversion and optimized H_(2)O_(2)utilization,the optimal Fe–BiOBr–2 catalyst showed an excellent atrazine removal efficiency of 97.61%in 120 min,which is superior than the traditional homogeneous Fenton and the majority of heterogeneous processes documented in the literature.In this photo–Fenton system,hydroxyl(·OH)and superoxide(·O_(2)^(-))radicals were dominant active species contributed to the oxidative degradation of atrazine.Due to the production of various active radicals,five degradation pathways were proposed based on the identification of intermediates and degradation products.Overall,this work not only demonstrates a fundamental insight into creating highly efficient and atom economic photo-Fenton systems,but also provides a complementary strategy for the treatment of organic pollutants in water.

关键词： Bismuth oxybromide Photo–Fenton Atrazine Catalytic degradation