Predictive Decision and Reliable Accessing for UAV Communication in Space-Air-Ground Integrated Networks

The cooperation of multiple Unmanned Aerial Vehicles(UAVs) has become a promising scenario in Space-Air-Ground Integrated Networks(SAGINs) recently due to their widespread applications,where wireless communication is a basic necessity and is normally categorized into control and nonpayload communication(CNPC) as well as payload communication. In this paper, we attempt to tackle two challenges of UAV communication respectively on establishing reliable CNPC links against the high mobility of UAVs as well as changeable communication conditions, and on offering dynamic resource optimization for Quality-of-Service(QoS) guaranteed payload communication with variable link connectivity. Firstly, we propose the concept of air controlling center(ACC), a virtual application equipped on the infrastructure in SAGINs, which can collect global information for estimating UAV trajectory and communication channels. We then introduce the knapsack problem for modelling resource optimization of UAV communication in order to provide optimal access points for both CNPC and payload communication. Meanwhile, using the air controlling information, predictive decision algorithm and handover strategy are introduced for the reliable connection with multiple access points. Simulation results demonstrate that our proposal ensures an approximate always-on reliable accessing of communication links and outperforms the existing methods against high mobility,sparse distribution, and physical obstacles.

Fiber-Wireless Integrated Reliable Access Network for Mobile Fronthaul Using Synclastic Uniform Circular Array with Dual-Mode OAM Multiplexing

We propose an access network that integrates fiber and wireless for mobile fronthaul(MFH)with simple protection capabilities,using dualmode orbital angular momentum(OAM)multiplexing.We experimentally demonstrate a 3.35 Gbit/s DMT-32QAM preequalized system with 10 km and 15 km fiber links in the 5.9 GHz band;then there is a link of two channels with a 0.5 m wireless link.

Non-cooperative game for network access selection in heterogeneous integrated networks

The integration of different heterogeneous access networks is one of the remarkable characteristics of the next generation network,in which users with multi-network interface terminals can independently select access network to obtain the most desired service.A kind of unified quantification model of non-monotone quality of service(QoS) and a model of non-cooperative game between users and networks are proposed for heterogeneous network access selection.An optimal network pricing mechanism could be formulated by using a novel strategy which is used in this non-cooperative game model to balance the interests of both the users and the networks.This access network selection mechanism could select the most suitable network for users,and it also could provide the basis when formulating QoS standards in heterogeneous integrated networks.The simulation results show that this network selection decision-making algorithm can meet the users' demand for different levels service in different scenes and it can also avoid network congestion caused by unbalanced load.

THMAS-1: A High-Performance ISDN/ATM Multimedia Integrated Access System for Real-time Interactive Distance Learning

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Secure Remote Access IPSEC Virtual Private Network to University Network System

With the popularity of the Internet and improvement of information technology,digital information sharing increasingly becomes the trend.More and More universities pay attention to the digital campus,and the construction of digital library has become the focus of digital campus.A set of manageable,authenticated and secure solutions are needed for remote access to make the campus network be a transit point for the outside users.Remote Access IPSEC Virtual Private Network gives the solution of remote access to e-library resources,networks resources and so on very safely through a public network.It establishes a safe and stable tunnel which encrypts the data passing through it with robust secured algorithms.It is to establish a virtual private network in Internet,so that the two long-distance network users can transmit data to each other in a dedicated network channel.Using this technology,multi-network campus can communicate securely in the unreliable public internet.

Research on Traffic Accessibility and Transportation Integration Level of Chang-Zhu-Tan City Group in China

Aiming at the problem of lack of data model to analyze the level of transportation integration, the paper taking Changsha-Zhuzhou-Xiangtan City Group of China as the research object, based on the Gravity measurement model, transportation comprehensive distance model, weighted road density model, analysis of Changsha-Zhuzhou-Xiangtan City Group accessibility and transportation integration level. A new method to measure the level of traffic integration is proposed and verified by the road network data and socio-economic data of Changsha-Zhuzhou-Xiangtan City Group. The results show that: Changsha-Zhuzhou-Xiangtan City Group traffic accessibility was “point to surface” shape distribution, taking the core region of Changsha as the optimal, Xiangtan, Zhuzhou, Changsha County next, in remote Yanling County, Chaling county has the lowest accessibility;the correlation between traffic network connection degree and economic connection degree reached 0.871, indicating that the transportation integration level of urban agglomerations has a high degree of fit with the level of economic integration. The research results on the one hand for the Chang-Zhuzhou-Xiangtan urban agglomeration traffic present situation to make an annotation;on the other hand, that provide a reference for further optimization of Changsha-Zhuzhou-Xiangtan urban agglomeration traffic planning.

Design and application of integrated automation system platform of mine based on PON

本文分析了基于PON(无源光网络)的矿山综合自动化系统平台的设计与集成应用。本章从系统硬件及软件设计等方面对其进行了详细的描述。结果表明:该系统可有效提高工作效率,降低管理成本。介绍了PON的基本工作原理及其结构,并结合某矿山信息传输的特点将基于PON的接入网和以太网相结合设计了一套综合自动化网络平台。

面向6G全域融合的智能接入关键技术综述

针对空天地一体化接入网络,该文在总结相关研究的基础上,阐述了未来空天地一体化接入架构的关键技术,分析了空口技术、多址技术、干扰分析、计算技术和人工智能(AI)技术等几个重点方向的研究进展,提出了多种接入形式并存的灵活性网络架构。针对6G全域融合网络接入的重点研究问题,结合用户的服务质量需求,构建了一体化AI赋能架构,提出了大规模混合多址接入及弹性资源适配策略。基于网络架构立体化、网络协同传输、一体化网络资源管理、未来空天地接入技术以及网络协同计算等未来重点研究方向进行了讨论和展望。

基站无线回传技术研究

有些场景光纤传输部署困难、成本高、周期长,需研究使用无线传输将基站和核心网连通。首先介绍了无线回传的应用场景,详细论述和对比了实现无线回传的可行技术方案,分析了无线回传中头开销、MTU和时延的影响,为特定场景使用无线回传方案提供了参考。

适应5G及边缘算力的多业务综合接入解决方案探讨

首先说明5G、边缘算力需求增加,多业务综合接入方式建设必要性,再提出多业务综合接入点位的建设思路,多业务综合接入点的规划流程、设置方法,多业务综合接入的网络构建拓扑方式,提出室外一体化机柜的解决方案、特点、各种典型应用场景、设置建议等。最后对建设形式及站址选择进行了阐述。

基于用户协作PDMA的星地融合网络性能分析

将用户协作PDMA技术引入到星地融合网络下行链路系统的通信中,目的是当卫星向用户发送PDMA叠加信号时,其中最佳信道用户能够作为半双工中继节点解码和转发其他用户的信息,以提高弱用户的通信性能。文章推导出三用户处于不同程度衰落情况下系统的中断概率和遍历容量表达式,并通过仿真验证了理论分析的正确性,而且证实了与传统的正交多址接入及非协作PDMA系统相比,用户协作PDMA方案可以获得更高的中断性能和遍历容量。

湖州市推进城乡一体化发展的交通网络通达性研究

文章从交通网络通达性的视角阐述当前湖州市区域内交通网络体系的现状,并根据现有交通网络存在的不足,从完善交通网络体系、合理配置资源的角度,提出促进城乡一体化的交通设施投资策略和政策建议,为各级政府和部门决策提供有效支持。

基于速率分割的可重构智能表面辅助星地融合网络鲁棒安全传输方案

首先,考虑一个可重构智能表面(RIS)辅助的星地融合网络,卫星采用速率分割多址技术服务多个地球站,而地面基站则在RIS的协助下利用多播技术服务多个地面用户,同时还存在多个窃听者企图获取卫星的隐私信号。其次,在仅已知窃听者非完美信道状态信息的条件下,以所有用户的通信质量要求及最大窃听概率为约束条件,建立一个以最小化系统总发射功率为目标函数的联合优化问题。为了求解该非凸问题,采用S-procedure和连续凸逼近方法将复杂的窃听概率约束转化为可行的凸约束;利用基于核范数的惩罚函数方法提出一种鲁棒联合优化算法以迭代求解波束成形权矢量和发射功率。最后,计算机仿真结果验证了所提传输方案的有效性和优越性。

智能矿山基础平台建设及其发展趋势

智能矿山是数字矿山和综合自动化系统发展的延续,相较于数字矿山和矿山综合自动化系统,智能矿山对基础平台提出了更高要求。智能矿山基础平台分网络平台和数据平台两大部分,网络平台分为主干网和接入网。主干网经历了工业总线网、100 Mbit/s工业以太网、1 000 Mbit/s工业以太网和10 Gbit/s工业以太网的发展过程。分析了主干网从工业总线到10 Gbit/s工业以太网的发展过程、各自的优缺点及适用性,指出工业总线网和100 Mbit/s工业以太网不适合作为智能矿山主干网,而1 000 Mbit/s和10 Gbit/s工业以太网目前是智能矿山主干网络的首选。通过分析智能矿山接入网的建设需求,指出智能矿山的接入网应具备无盲区接入和底层计算能力。目前的无线接入网仍难以具备上述能力:如漏泄通信系统属于半无线方式,应用场合受限,速率不高;5G主要为无线传输网络,有较为灵活的速率适应性,适合作为纯接入传输网络,由于不具备自组网和底层计算能力,在无盲区监测应用方面受到一定限制;无线传感器网络具备一定自给网及底层计算能力,但速率较低,特别是矿山井下多跳使用时速率明显下降,且功耗上升,从而降低计算能力和自组网能力。因此,需要研发新的适应智能矿山需求的接入网设备。针对分立服务器和简单虚拟服务器的数据平台方式已不能适应智能矿山对数据平台的要求,分析了数据平台的超融合服务平台架构及其关键技术、超融合服务的特点及对智能矿山建设的适应性,指出超融合服务器是智能矿山数据平台的发展方向。

空地一体网络接入选择与切换控制技术研究

随着卫星网络的加速发展,空地一体网络逐渐受到关注,并将成为未来网络的发展趋势。接入选择和切换控制技术作为该网络的基础,对网络性能和用户体验产生了重要影响。基于此,对空地一体网络架构的发展和现状进行概述,总结了空地一体网络中接入与切换过程面临的问题,针对空地一体网络的接入与切换管理需求,介绍了相关的解决方案并进行了详细分析,对空地一体网络的未来发展方向进行了讨论。

空天地海一体化的大规模随机接入方法研究

空天地海一体化网络为解决承载大规模设备接入问题提供一种新的方案与思路。针对日益增长的大规模设备接入问题,提出了基于机器学习的随机接入方法,增加在大规模设备接入情形下的接入成功设备的数量。先阐述了空天地海一体化网络下的MAC层系统模型,接着对比分析了五种随机接入方法。最终实验结果表明,所提出的适应性随机接入方法能够增加网络系统的接入成功的设备数量。

非完美条件下的非正交多址接入星地融合网络性能分析

随着星地融合网络(ISTNs)的快速发展,大量的传感器和无线设备都有无线服务的接入需求,从而对星地融合网络的频谱效率和服务质量提出了新的挑战。不同于传统的正交多址接入技术,非正交多址接入(NOMA)技术可在相同的频率下传输不同用户的信号,其被认作为提高星地融合网络频谱效率的有效方法,从而被广泛研究。目前,针对NOMA和星地融合网络的研究大多都是在理想条件下进行的,由此该文研究更加实际的情况,即在非完美串行干扰消除(SIC)、信道估计误差和同频干扰下,对星地融合网络的性能进行研究。该文在假设卫星端和地面端均采用多天线的前提下,推导了系统遍历容量的闭式表达式,验证了非完美条件对于系统性能的影响。同时蒙特卡罗仿真验证了理论分析和推导的正确性。

面向6G通感算深度融合的服务化无线接入网试验平台

为了满足6G多样化的服务需求,搭建了面向6G通感算深度融合的服务化无线接入网试验平台。该平台采用服务化架构:首先,无线接入网的控制面与用户面解耦,为用户提供更好的服务;然后,将集中式控制面解耦为独立的网络功能,加快服务的响应速率;最后,按需编排与管理网络功能与资源,实现定制化服务。实验结果表明:与传统方案相比,服务化无线接入网服务响应时间降低约30%,平均信令开销减少约50%,可以为用户提供更好的服务。

Ergodic sum rate for uplink NOMA transmission in satellite-aerial-ground integrated networks

The application of Non-Orthogonal Multiple Access(NOMA) technology into satelliteaerial-ground integrated networks can meet the requirements of ultra-high rate and massive connectivity for the Sixth-Generation(6G) communication systems. We consider an uplink NOMA scenario for such a satellite-aerial-ground integrated network where multiple users communicate with satellite under the help of an Unmanned Aerial Vehicle(UAV) as an aerial relay equipped with a phased array. Supposing that buffer-aided decode-and-forward protocol is adopted at the UAV relay, we first formulate an optimization problem to maximize Ergodic Sum Rate(ESR) of the considered system subject to individual power constraint and quality-of-service constraint of each user.Then, with known imperfect channel state information of each user, we propose a joint power allocation and robust Beam Forming(BF) iterative algorithm to maximize ESR for the user-to-UAV link. Besides, to take the advantages of Free-Space Optical(FSO) and millimeter Wave(mmWave)communications, we present a switch-based hybrid FSO/mmWave scheme and a robust BF algorithm for the UAV-to-satellite link to achieve higher rate. Moreover, a closed-form ESR expression is derived. Finally, the effectiveness and correctness of the proposed solutions are verified by numerical simulations, and the performance evaluation results show that the proposed solutions not only achieve performance enhancement and robustness, but also outperform the orthogonal multiple access significantly.

VBR-GAM的SCMA高维度码本设计

在物理层,为了解决海量用户接入问题而使用稀疏码多址接入(Sparse Code Multiple Access,SCMA)技术。现阶段有关SCMA的研究中,除了SCMA多用户检测技术的研究,还会关注SCMA系统码本设计,性能良好的SCMA码本不仅能在多用户检测过程中提升其抗噪性能,而且能够降低检测复杂度。传统的码本设计方案主要针对低维度码本进行研究,而且所设计的码本方案大部分都是基于QAM、TCM、Lattice展开的,对于高维度码本很少涉足与研究。对此主要聚焦一种新型码本设计——黄金角度调制(Golden Angle Modulation,GAM),并在此基础上提出可变比特率(Variable Bit Rate,VBR)GAM码本设计。仿真结果表明VBR-GAM码本可以灵活满足不同业务的需求,也可以通过改变调制阶数来改变不同优先级用户的功率效率,从而实现码本的变速率传输,相比传统的GAM码本性能更优,可实现更低的误码率。