MEC-Empowered Non-Terrestrial Network for 6G Wide-Area Time-Sensitive Internet of Things

In the upcoming sixth-generation(6G)era,the demand for constructing a wide-area time-sensitive Internet of Things(IoT)continues to increase.As conventional cellular technologies are difficult to directly use for wide-area time-sensitive IoT,it is beneficial to use non-terrestrial infrastructures,including satellites and unmanned aerial vehicles(UAVs).Thus,we can build a non-terrestrial network(NTN)using a cell-free architecture.Driven by the time-sensitive requirements and uneven distribution of IoT devices,the NTN must be empowered using mobile edge computing(MEC)while providing oasisoriented on-demand coverage for devices.Nevertheless,communication and MEC systems are coupled with each other under the influence of a complex propagation environment in the MEC-empowered NTN,which makes it difficult to coordinate the resources.In this study,we propose a process-oriented framework to design communication and MEC systems in a time-division manner.In this framework,large-scale channel state information(CSI)is used to characterize the complex propagation environment at an affordable cost,where a nonconvex latency minimization problem is formulated.Subsequently,the approximated problem is provided,and it can be decomposed into sub-problems.These sub-problems are then solved iteratively.The simulation results demonstrated the superiority of the proposed process-oriented scheme over other algorithms,implied that the payload deployments of UAVs should be appropriately predesigned to improve the efficiency of using resources,and confirmed that it is advantageous to integrate NTN with MEC for wide-area time-sensitive IoT.

NTN非地面网络技术研究与应用综述

目前,6G进入标准窗口期,有望实现卫星通信系统与6G系统级的有机融合,创建涵盖“空、天、地、海”的综合网络,建立面向未来的、全方位覆盖、多场景应用、普遍存在的移动通信基础设施。非地面网络(Non-Terrestrial Network,NTN)是面向地面通信与卫星通信的多层无线通信网络,能够实现天地一体的泛在连接,满足随时随地可靠安全的人、机、物之间的无限连接需求,是6G的关键技术之一。文章基于NTN技术的发展过程、3GPP相关标准进展,通过分析关键技术、目前面临的挑战以及未来发展趋势,对应用场景进行了划分,以期为相关创新主体以及各产业链的研发者提供参考。

Spatio-Temporal Service Analysis in Multi-Layer Non-Terrestrial Networks

In the advent of the 6G era, non-terrestrial networks (NTN) with expansive coverage are being increasingly recognized as a vital supplement to cellular networks for facilitating seamless communication. The intricate interplay between network performance and service quality necessitates a thorough investigation into the modeling and analysis of services for efficient construction of NTN.Previous studies on service analysis, predominantly focused on terrestrial networks,fall short in addressing the unique challenges posed by NTN,particularly those related to platform distribution and antenna gain modeling. This deficiency in research,coupled with the varying preferences of users for different network types, forms the basis of this study. This paper explores the spatio-temporal characteristics of services within a multi-layered NTN framework.In this context,the spatial distribution of the platforms is modeled using a binomial point process, and the antennas are characterized by a sectorized beam pattern. We derive the closed-form expressions for the association probability,the number of accessed users, and the arrival rate of services with certain delay requirements towards different types of NTN. Simulation results are provided to evaluate the influence of various parameters on the association probability, the number of accessed users, and the total arrival rate of services. The number of satellites can be determined to achieve the optimal system utility,balancing the accessed services, offloading effects, and launching costs. This initial investigation lays the groundwork for further theoretical progress in the service analysis and platform deployment of NTN.

5G NTN网络架构标准化演进的思考

目前,5G正在全球范围内大规模商用。然而,传统5G网络在部署方面受到地理条件和成本的制约,还无法实现全球的无缝覆盖。近年来,卫星通信技术得到了飞速发展,让5G全域覆盖成为可能,5G和卫星的融合,即5G非地面网络(non-terrestrial network,NTN)技术成为当前业界新的热点。国际标准化组织3GPP目前已经初步完成了基于透明转发架构的5G NTN技术规范。首先,介绍了5G NTN网络架构的标准化现状;其次,分析了5G NTN当前网络架构上存在的不足或问题;最后,针对星间链路搭建、星地分流等问题提出了基于集成接入和回传的网络架构、NTN自适应网络架构以及NTN多连接网络架构3种5G NTN网络架构增强和优化方案,为5G NTN后续的研究、标准化以及网络部署提供有价值的建议和参考。

NTN非地面网络技术发展综述

卫星互联网技术通过卫星提供互联网接入服务,满足地面蜂窝网络尚未覆盖地区的通信需求。本文详细介绍了卫星互联网的发展、NTN非地面网络技术标准进展、透明载荷与再生载荷两种网络架构,以及NTN技术目前面临的挑战。这些信息为进一步研究空天地一体化和提升偏远地区用户广播电视观看和通信体验奠定了基础。

星地融合多场景应用及解决方案

星地网络天然存在较强的互补性,为实现广域无缝覆盖,星地网络融合是未来网络演进的必然趋势。目前,受限于星地网络在体制、架构以及应用场景的差异性,星地网络融合程度较低。为快速推进融合网络发展,迫切需要开展星地融合场景与解决方案的挖掘探索。为此,提出了非地面网络与地面蜂窝网络协同应用场景以及潜在的增强方案,以实现星地网络资源的统一协调,提升资源利用率与用户体验,并进一步展望了未来星地融合网络发展前景。

面向智慧海洋场景的5G-A关键技术的研究与应用

智慧海洋是实现海洋强国战略的必由之路。5G-A技术是基于5G技术的增强和演进,其引入的基于NTN非地面网络的天地一体、通信感知一体、内生智能等全新的革命性技术,加快推动智慧海洋的发展。面向海域场景,通过对5G-A NTN网络天地一体关键技术的网络架构、时频同步、时序管理、传输调度和移动性管理进行分析,实现面向智慧海洋的5G-A海天一体组网方案以及5G专网+双星深度融合,实现5G+智慧海洋的信息通信全面升级;通过对5G-A通感一体关键技术的工作模式、通感架构、空口设计、目标特征智能识别进行分析,基于海域不同的场景特点和感知指标需求,分场景设计通感一体部署方案,实现海上船只智能精准识别,实时智能海事监控,有效保障海上航线安全。

多波束卫星通信系统中的非线性预编码算法研究

非地面网络(3GPP NTN)是5G演进以及6G网络中的重要组成部分,为了增强卫星容量和频谱效率,基于相控阵的密集多波束、同频部署已逐渐成为研究热点。由于波束成形中旁瓣功率泄露随着波束数增加会造成严重波束间叠加干扰,亟需低复杂度多用户干扰消除方案。从预编码技术角度出发,探讨了非线性预编码在卫星通信系统中的应用和优化方法,并通过实际硬件平台测试,验证了在5G NR基带链路中实现该方案的有效性和先进性。

Space-Air-Ground Integrated Network (SAGIN) for 6G: Requirements, Architecture and Challenges

As the fifth-generation(5G)mobile communication network may not meet the requirements of emerging technologies and applications,including ubiquitous coverage,industrial internet of things(IIoT),ubiquitous artificial intelligence(AI),digital twins(DT),etc.,this paper aims to explore a novel space-air-ground integrated network(SAGIN)architecture to support these new requirements for the sixth-generation(6G)mobile communication network in a flexible,low-latency and efficient manner.Specifically,we first review the evolution of the mobile communication network,followed by the application and technology requirements of 6G.Then the current 5G non-terrestrial network(NTN)architecture in supporting the new requirements is deeply analyzed.After that,we proposes a new flexible,low-latency and flat SAGIN architecture,and presents corresponding use cases.Finally,the future research directions are discussed.

Double-Edge Intelligent Integrated Satellite Terrestrial Networks

The efficient integration of satellite and terrestrial networks has become an important component for 6 G wireless architectures to provide highly reliable and secure connectivity over a wide geographical area.As the satellite and cellular networks are developed separately these years,the integrated network should synergize the communication,storage,computation capabilities of both sides towards an intelligent system more than mere consideration of coexistence.This has motivated us to develop double-edge intelligent integrated satellite and terrestrial networks(DILIGENT).Leveraging the boost development of multi-access edge computing(MEC)technology and artificial intelligence(AI),the framework is entitled with the systematic learning and adaptive network management of satellite and cellular networks.In this article,we provide a brief review of the state-of-art contributions from the perspective of academic research and standardization.Then we present the overall design of the proposed DILIGENT architecture,where the advantages are discussed and summarized.Strategies of task offloading,content caching and distribution are presented.Numerical results show that the proposed network architecture outperforms the existing integrated networks.

Study on Security of 5G and Satellite Converged Communication Network

The 5G and satellite converged communication network(5G SCCN)is an impor⁃tant component of the integration of satellite-terrestrial networks,the national science,and technology major projects towards 2030.Security is the key to ensuring its operation,but at present,the research in this area has just started in our country.Based on the network char⁃acteristics and security risks,we propose the security architecture of the 5G SCCN and sys⁃tematically sort out the key protection technologies and improvement directions.In particu⁃lar,unique thinking on the security of lightweight data communication and design reference for the 5G SCCN network architecture is presented.It is expected to provide a piece of refer⁃ence for the follow-up 5G SCCN security technology research,standard evolution,and indus⁃trialization.

一种面向NTN网络转发模块的研究实现

NTN(node-to-node)横联远距离无线移动通信系统转发模块是基于MAC地址转发原理,每个节点维护一张包含下一跳节点信息的路由表。文章在当前无线自组网路由协议的理想要求上,比较路由协议的常规问题,分析转发模块设计方案的特点,同时从6个方面研究转发模块。测试结果表明,该MAC协议转发模块可实现全网MAC的学习、转发路径的计算、拓扑去环功能,支持横联内部设备相互通信、外设与外设通信。

星地网络融合架构及组网场景分析

随着网络的不断发展,未来通信网络服务范围将扩展至空天地,卫星网络成为未来重要发展方向。5G与卫星网络融合能够为用户提供更可靠的服务体验,降低运营商网络部署成本。从核心网出发,分析卫星网络与通信网络融合发展现状,探索未来融合网络可能的网络形态,选择边缘计算和VN组通信2个典型场景,详细分析了其面临的问题,并提出了相应的技术方案。

面向5G-Advanced的天地一体化网络定位增强技术研究

面向天地一体化网络中的用户设备定位和位置验证需求,3GPP Rel-18正在开展针对NTN的4G和5G定位协议演进增强。结合天地一体化网络定位业务特性和3GPP Rel-18 NTN的定位增强目标,提出了面向5G-Advanced的天地一体化网络定位增强技术和方案。该方案可以实现NTN网络UE的快速准确定位和位置验证,为NTN跨境服务等提供标准技术支持,保障天地一体化网络满足其服务地区的法规和业务需求。

Performance Analysis of the Packet-Based PNT Service in NGSO Broadband Satellite Communication Systems

Providing alternative PNT service to GNSS-challenged users will be an important function of next-generation NGSO broadband satellite communication systems.Herein,a packet-based PNT service architecture in NGSO broadband systems is proposed in which a primary satellite and selected assistant satellites work together to provide PNT service to requesting users.Its positioning performance bounds are mathematically formulated by rigorously analyzing the bounds constrained by different waveforms.Simulations are conducted on different configurations of Walker Delta MEO constellations and Walker Star LEO constellations for corroboration,revealing the following:(1)Both MEO and LEO constellations achieve sub-meter-level positioning precision given enough satellites.(2)Compared to the GNSS Doppler-based velocity estimation method,the position advance based velocity estimation algorithm is more precise and applicable to the PNT service in NGSO broadband systems.(3)To provide PNT service to users in GNSS-challenged environments,the primary and each assistant satellite need only∼0.1‰of the time of one downlink beam.

珠江三角洲新生儿转运网络10年工作及效果报告

【目的】 报告和评价珠江三角洲新生儿转运网络（ＮＴＮ）１０ 年工作及其效果。【方法】 介绍新生儿转运网络方法和分析有关效果的资料。【结果】 转运网络现有８７ 家医院；１０ 年共转运急、危重症新生儿８ １２４ 例，转运途中病死率为０ ．４３ ％ ；第三级ＮＩＣＵ 收容８ ０８９ 例，病死率为２ ．０７ ％ 。【结论】 该ＮＴＮ 所实行的运转机制合理适用，促进了网络单位包括三级ＮＩＣＵ 的进步提高，是降低新生儿死亡率的重要措施。

基于Agilent86100取样示波器的时域网络分析系统(英文)

本文根据Nose-to-Nose校准技术的基本原理,提出了利用NTN技术和Agilent86100取样示波器,构建时域网络分析系统的新方法。该方法成功地实现了对标称带宽50GHz的同轴适配器、同轴电缆等器件的测量。通过数字信号处理不仅可以得到这些器件的全部时域特性(冲激响应、阶跃响应、上升时间和过冲等),而且还能得到其全部频域特性(幅频特性、相频特性和带宽等)。扫频源比对实验证明该方法是有效的。

空天地一体化网络技术展望

作为实现全球网络无缝覆盖的重要手段,空天地一体化是未来移动通信的重要愿景之一。简要回顾了地面无线移动通信和卫星通信的发展历史,论证了空天地一体化网络技术研究的必要性,并首次定义了网络融合发展的不同层次。随后针对空天地一体化网络中的网络架构、关键技术、融合终端3个方面,展望了未来网络融合的演进。

5G-A空天地融合核心网方案及关键技术

5G Advanced将融合地面基站、中高空飞行器、卫星等各类网络节点,实现全球无缝地理覆盖。在运营商网络中,NTN作为新的接入类型和回传类型,需要考虑融合协同问题。提出了空天地融合核心网方案,分析了业务SLA保障和QoS控制增强、基于AI的用户面策略、智能算网协同调度、卫星非连续覆盖等待定时器及自适应智能化运维和管理等关键技术,为空天地融合核心网实现网络动态协同提供了有效、可行的实现方法。

基于混合树结构神经网络的隐式篇章关系识别

隐式篇章关系识别的主要挑战是如何表示两个文本单元的语义信息.由于句子的语义信息往往由语法树中的信息焦点(谓词部分)所决定,所以关注信息焦点可以提升篇章关系识别的效果.为了增强信息焦点的作用,引入树状长短时记忆(tree-structured long short-term memory,Tree-LSTM)网络,使用其遗忘门的特性区别对待不同孩子节点的信息.最后利用神经张量网络(neural tensor network,NTN)来计算两个句子语义向量之间的关系.基于PDTB2.0(Penn Discourse Treebank)语料数据进行实验,实验结果表明混合树结构神经网络比传统的RNN模型在大部分关系中的Fscore上提高了3.0%左右.