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Investigation and Comparison of 5G Channel Models: From Qua DRi Ga, NYUSIM,and MG5G Perspectives

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Chinese Journal of Electronics 2022年第1期31卷 1-17页

作者： PANG lihua ZHANG Jin ZHANG Yang HUANG Xinyi CHEN Yijian li jiandong School of Communication and Information Engineering Xi'an University of Science and Technology State Key Laboratory of Integrated Service Networks Xidian University National Mobile Communications Research Laboratory Southeast University Algorithm Department ZTE Corporation

This paper investigates and compares three channel models for the fifth generation(5 G) wireless communications: the quasi deterministic radio channel generator(Qua DRi Ga), the NYUSIM channel simulator model developed by New York University, and the more general 5 G(MG5 G) channel model. First, the characteristics of the modeling processes of the three models are introduced from the perspective of model ***, the small-scale parameter modeling strategies of the three models are compared from space/time/frequency domains as well as polarization aspect. In particular, the drifting of small-scale parameters is introduced in ***, through the simulation results of angular power spectrum, Doppler power spectrum density, temporal autocorrelation function, power delay profile, frequency correlation function, channel capacity, and eigenvalue distribution, the three models are comprehensively investigated. According to the simulation results, we clearly analyze the impact of the modeling strategy on the three channel models and give certain evaluations and suggestion which lay a solid foundation for link and system-level simulations for 5 G transmission algorithms.

关键词： Channel models 5G mobile communication Antenna arrays Atmospheric modeling Analytical models Delays Solid modeling

Coverage enhancement for 6G satellite-terrestrial integrated networks: performance metrics, constellation configuration and resource allocation

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Science China(Information Sciences) 2023年第3期66卷 40-59页

作者： Min SHENG Di ZHOU Weigang BAI Junyu liU Haoran li Yan SHI jiandong li State Key Laboratory of Integrated Service Networks Xidian University Department of Broadband Communication Peng Cheng Laboratory

Since the base station-centric wireless coverage mode of 5G is difficult to support future stereoscopic global wireless coverage demands, the future infrastructure of 6G satellite-terrestrial integrated network(STIN) with mega constellations will extend from the terrestrial network to the integrated satellite-terrestrial architecture, so as to realize the improvement of wireless coverage capability through extending the spatial and temporal coverage. However, what are the specific quantitative indicators of wireless coverage? What is the basis for the effect of network configuration with mega constellations on coverage performance? How to form non-uniform coverage through intelligent resource scheduling to match non-uniformly distributed service requirements in the future 6G STIN? The aforementioned unknown fundamental problems have become a bottleneck restricting the further development of coverage expansion in the future 6G STIN. In this paper,we start with the evolution route of wireless coverage and the vision of 6G coverage and propose coverage performance evaluation metrics in 6G STINs from the perspective of signal coverage, capacity coverage, and service coverage. Furthermore, we investigate the relationship between coverage structure and coverage capability in 6G STINs with mega constellations and we find network structure characteristics suitable for 6G non-uniform service requirements, thus guiding constellation design in 6G STINs by analyzing and comparing the coverage performance of several typical mega constellations. Afterwards, we explore the application of artificial intelligence in resource collaboration to provide technology reference to enhance coverage capability for dynamic 6G service demands. Finally, we analyze possible technical challenges for improving service coverage performance in 6G STINs to provide researchers with new ideas.

关键词： 6G satellite-terrestrial integrated networks on-demand wireless coverage performance metrics constellation configuration intelligent resource scheduling

Spectrum-Efficient User Association in Caching Enabled Dense Small Cell Network

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China Communications 2023年第3期20卷 86-104页

作者： Junyu liu Min Sheng Xiaona Zhao Shuang Ni jiandong li State Key Laboratory of ISN Xidian UniversityXi’an 710071China Department of Broadband Communication Peng Cheng LaboratoryShenzhen 518055China

In this paper,we reveal the fundamental limitation of network densification on the performance of caching enabled small cell network(CSCN)under two typical user association rules,namely,contentand distance-based *** indicates that immoderately caching content would significantly change the interference distribution in CSCN,which may degrade the network area spectral efficiency(ASE).Meanwhile,it is shown that content-based rule outperforms the distance-based rule in terms of network ASE only when small cell base stations(BSs)are sparsely deployed with low decoding ***,it is proved that network ASE under distance-based user association serves as the upper bound of that under content-based rule in dense BS *** enable more spectrum-efficient user association in dense CSCN,we further optimize network ASE by designing a probabilistic content retrieving strategy based on distance-based *** the optimized retrieving probability,network ASE could be substantially enhanced and even increase with the growing BS density in dense BS regime.

关键词： caching dense network user association

6G Service Coverage with Mega Satellite Constellations

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China Communications 2022年第1期19卷 64-76页

作者： Min Sheng Di Zhou Weigang Bai Junyu liu jiandong li State Key Laboratory of Integrated Service Networks Xidian UniversityXi’anShaanxi710071China

The rapid development and continuous updating of the mega satellite constellation(MSC)have brought new visions for the future 6G coverage extension, where the global seamless signal coverage can realize ubiquitous services for user terminals. However, global traffic demands present nonuniform characteristics. Therefore, how to ensure the on-demand service coverage for the specific traffic demand, i.e., the ratio of traffic density to service requirement per unit area, is the core issue of 6G wireless coverage extension exploiting the MSC. To this regard, this paper first discusses the open challenges to reveal the future direction of 6G wireless coverage extension from the perspective of key factors affecting service coverage performance, i.e., the network access capacity, space segment capacity and their matchingrelationship. Furthermore, we elaborate on the key factors affecting effective matchings of the aforementioned aspects, thereby improving service coverage capability.

关键词： 6G mega satellite constellations on-demand service coverage un-uniform traffic demands resource management

Enabling Efficient Caching in High Mobility UAV Communications Network under limited Backhaul

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China Communications 2022年第10期19卷 207-219页

作者： Yan Wu jiandong li Junyu liu Min Sheng Chenxi Zhao State Key Laboratory of Integrated Service Networks Xidian UniversityXi'anShaanxi 710071China

Due to flexible deployment,unmanned aerial vehicle(UAV)mounted aerial access points are capable of expanding the coverage capabilities of existing terrestrial base stations(TBSs).Different from TBSs,however,UAV access points(UAPs)are of high mobility in horizontal and vertical dimensions,which may deteriorate the coverage ***,the mobility of UAPs would as well increase the pressure of wireless *** this light,we investigate the performance of the cache-enabled UAV communications network(CUCN)in terms of network spatial throughput(ST)by analyzing the line of sight(LoS)connections and non-line of sight(NLoS)*** is found that the network ST is exponentially decreased with the square of UAP ***,contrary to intuition,a large cache size may deteriorate the network ST when UAPs are *** reason is that a large cache size increases the hit probability,which may increase the activation of UAPs and consequently result in complicated *** to maximize the network ST,we optimize the cache strategy under limited ***,the results show that network ST could be substantially improved by the optimized cache strategy and the performance degeneration brought by UAP high mobility could be even eliminated especially when the UAP altitude is high.

关键词： caching optimization UAV communications network spatial throughput stochastic geometry aerial access point

重型商用车瞬态工况NO_(x)排放特征分析

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汽车工程师 2024年第6期 42-48页

作者：刘刚李静静王兴元李建东内燃机可靠性国家重点实验室潍坊261061 潍柴动力股份有限公司发动机研究院潍坊261061

为分析瞬态工况对重型商用车NO_(x)排放的影响,通过对重型商用车瞬态运行工况进行分类,在冷车起步、行驶中停车起步、通过高速公路收费口、超越加速4个典型工况下针对NO_(x)排放特征开展试验研究,结果表明:瞬态工况会引起NO_(x)排放量升... 详细信息

为分析瞬态工况对重型商用车NO_(x)排放的影响,通过对重型商用车瞬态运行工况进行分类,在冷车起步、行驶中停车起步、通过高速公路收费口、超越加速4个典型工况下针对NO_(x)排放特征开展试验研究,结果表明:瞬态工况会引起NO_(x)排放量升高,尿素溶液的消耗量相对于稳态工况增加了约0.86~4倍。

关键词：重型商用车瞬态工况 NO_(x)排放超越加速

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玉米小区五行分种机理分析与试验

农机化研究 2024年第11期46卷 13-20,28页

作者：代永波杨薇李建东高秀强迟鹏王笑康青岛农业大学机电工程学院山东青岛266109 中国农业机械化科学研究院集团有限公司北京100083 中国农业机械化科学研究院土壤植物机器系统技术国家重点实验室北京100083

为提高玉米小区五行播种机的分种均匀性,对玉米小区五行分种过程进行运动规律分析,采用离散元EDEM仿真软件,建立仿真模型;同时,以存种套筒直径、锥体角度、套筒提升速度为试验因素,以分种均匀性变异系数为试验指标,进行不同播量的三因... 详细信息

为提高玉米小区五行播种机的分种均匀性,对玉米小区五行分种过程进行运动规律分析,采用离散元EDEM仿真软件,建立仿真模型;同时,以存种套筒直径、锥体角度、套筒提升速度为试验因素,以分种均匀性变异系数为试验指标,进行不同播量的三因素三水平二次正交试验,探究各个因素对玉米小区五行播种分种均匀性的影响,确定最佳参数组合。仿真试验分析表明:在播种125粒和250粒时,借助Design expert软件求得玉米小区分种过程各因素的最优参数组合,即存种套筒直径为65mm、锥体角度为48°、套筒提升速度为0.24m/s时,玉米分种均匀性变异系数R_(1)为26.93%,R_(2)为27.82%。通过对玉米小区五行分种仿真分析,进行室内台架验证试验,结果表明:玉米分种均匀性变异系数R 1为28.06%,R 2为27.90%,实际人工投种与仿真分析结果误差分别为1.13%、0.08%,仿真试验分析与实际人工投种作业效果基本符合玉米小区五行实际播种需求。

关键词：小区播种机 EDEM 分种均匀性变异系数玉米

Energy-efficient trajectory planning and resource allocation in UAV communication networks under imperfect channel prediction

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Science China(Information Sciences) 2022年第12期65卷 248-262页

作者： Min SHENG Chenxi ZHAO Junyu liU Wei TENG Yanpeng DAI jiandong li State Key Laboratory of ISN Xidian University

In unmanned aerial vehicle(UAV) communication networks, trajectory planning and resource allocation(TPRA) under channel prediction obtains great attention due to its significant energy-saving of UAVs and user quality of service(QoS) gains. These potentials are primarily demonstrated under the assumption of perfect channel prediction. However, due to the rapid-varying features of air-to-ground channels,it is difficult to avoid the random channel prediction error(CPE), which may deteriorate the performance of TPRA. In this paper, we investigate the problem of energy-efficient TPRA considering random CPE. The problem is formulated as a mixed-integer non-convex optimization with chance constraints, which ensures that QoS is robust to random CPE. To solve it, we first transform the chance constraints into deterministic forms, which are further proved to be convex constraints by using the characteristic of quasiconvex ***, we design a modified successive convex approximation algorithm to iteratively achieve the optimal solution. To cater to the high-speed movement of UAVs, a low-complexity heuristic online algorithm is tailored. Specifically, we first relax the QoS constraints to find a feasible initial point and iteratively tighten the lower bound of QoS constraints to obtain a suboptimal solution. Simulation results show that the proposed algorithm can improve energy efficiency compared with the algorithm without prediction.

关键词： UAV communication networks trajectory planning resource allocation channel prediction

基于EDEM的小麦小区双圆盘开沟器仿真分析

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农机化研究 2024年第12期46卷 162-166,173页

作者：高秀强杨薇李建东代永波王笑康迟鹏青岛农业大学机电工程学院山东青岛266109 中国农业机械化科学研究院集团有限公司北京100083 中国农业机械化科学研究院土壤植物机器系统技术国家重点实验室北京100083

双圆盘开沟器具有不易堵塞和不乱土层优良作业的特点,为了配备在小型小麦播种机上,设计了一种小型双圆盘开沟器。为了获得双圆盘开沟器最小开沟阻力和最优的播深稳定性,以圆盘直径、圆盘聚点位置和圆盘夹角为试验因素,进行了仿真试验分... 详细信息

双圆盘开沟器具有不易堵塞和不乱土层优良作业的特点,为了配备在小型小麦播种机上,设计了一种小型双圆盘开沟器。为了获得双圆盘开沟器最小开沟阻力和最优的播深稳定性,以圆盘直径、圆盘聚点位置和圆盘夹角为试验因素,进行了仿真试验分析,得到最优工作参数数据(圆盘直径为210mm,圆盘聚点位置为60°,圆盘夹角为12.60°),此时双圆盘开沟器作业阻力为319.65N,开沟深度变异系数为7.51%。通过土槽试验加以验证,结果表明:与仿真试验相比,开沟作业阻力误差率为2.64%,开沟深度变异系数误差率为2.52%,仿真试验具有一定的可靠性,可为双圆盘开沟器设计优化提供理论依据。

关键词：小麦播种机双圆盘开沟器 EDEM 仿真试验

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