Joint User Association and Satellite Selection for Satellite-Terrestrial Integrated networks

In this paper, we investigate a cooperation mechanism for satellite-terrestrial integrated networks. The terrestrial relays act as the supplement of traditional small cells and cooperatively provide seamless coverage for users in the densely populated areas.To deal with the dynamic satellite backhaul links and backhaul capacity caused by the satellite mobility, severe co-channel interference in both satellite backhaul links and user links introduced by spectrum sharing,and the difference demands of users as well as heterogeneous characteristics of terrestrial backhaul and satellite backhaul, we propose a joint user association and satellite selection scheme to maximize the total sum rate. The optimization problem is formulated via jointly considering the influence of dynamic backhaul links, individual requirements and targeted interference management strategies, which is decomposed into two subproblems: user association and satellite selection. The user association is formulated as a nonconvex optimization problem, and solved through a low-complexity heuristic scheme to find the most suitable access point serving each user. Then, the satellite selection is resolved based on the cooperation among terrestrial relays to maximize the total backhaul capacity with the minimum date rate constraints. Finally,simulation results show the effectiveness of the proposed scheme in terms of total sum rate and power efficiency of TRs' backhaul.

Average Secrecy Capacity of the Reconfigurable Intelligent Surface-Assisted Integrated Satellite Unmanned Aerial Vehicle Relay Networks

Integrated satellite unmanned aerial vehicle relay networks(ISUAVRNs)have become a prominent topic in recent years.This paper investigates the average secrecy capacity(ASC)for reconfigurable intelligent surface(RIS)-enabled ISUAVRNs.Especially,an eve is considered to intercept the legitimate information from the considered secrecy system.Besides,we get detailed expressions for the ASC of the regarded secrecy system with the aid of the reconfigurable intelligent.Furthermore,to gain insightful results of the major parameters on the ASC in high signalto-noise ratio regime,the approximate investigations are further gotten,which give an efficient method to value the secrecy analysis.At last,some representative computer results are obtained to prove the theoretical findings.

Jamming-Aided Secure Communication in Ultra-Dense LEO Integrated Satellite-Terrestrial Networks

The ultra-dense low earth orbit(LEO)integrated satellite-terrestrial networks(UDLEO-ISTN)can bring lots of benefits in terms of wide coverage,high capacity,and strong robustness.Meanwhile,the broadcasting and open natures of satellite links also reveal many challenges for transmission security protection,especially for eavesdropping defence.How to efficiently take advantage of the LEO satellite’s density and ensure the secure communication by leveraging physical layer security with the cooperation of jammers deserves further investigation.To our knowledge,using satellites as jammers in UDLEO-ISTN is still a new problem since existing works mainly focused on this issue only from the aspect of terrestrial networks.To this end,we study in this paper the cooperative secrecy communication problem in UDLEOISTN by utilizing several satellites to send jamming signal to the eavesdroppers.An iterative scheme is proposed as our solution to maximize the system secrecy energy efficiency(SEE)via jointly optimizing transmit power allocation and user association.Extensive experiment results verify that our designed optimization scheme can significantly enhance the system SEE and achieve the optimal power allocation and user association strategies.

Design and verification of a satellite-terrestrial integrated IP network model for the Global Energy Interconnection

In order to meet the pressing demand for wide-area communication required by the Global Energy Interconnection(GEI),accelerating the construction of satellite-terrestrial Integra怕d networks that can achieve network extension and seamless global coverage has become the focus of power communication tech no logy development.In this study,we propose a satellite-terrestrial integrated network model that can support interconnection and interoperation on the IP layer between the satellite system and the怕rrestrial segment of the existing power communication system.First,the composition and function of the satellite-terrestrial collaborative network are explained.Then,the IP-based protocol stack is described,and a typical applicati on experime nt is con ducted to illustrate the particular process of this protocol stack.Fin ally,a use case of IP interconn ection that depends on GEO satellite communication is detailed.The experime ntal study has showed that the satellite-terrestrial collaborative network can efficiently support various IP applications for the GEI.

Blockchain Based Secure Relay Scheme for Space-Terrestrial Integrated Networks

The future 6G networks will integrates space and terrestrial networks to realize a fully connected world with extensive collaboration.However,how to build trust between multiple parties is a difficult problem for secure cooperation without a reliable third-party.Blockchain is a promising technology to solve this problem by converting the trust between multi-parties to the trust to the common shared data.Several works have proposed to apply the incentive mechanism in blockchain to encourage effective cooperation,but how to evaluate the cooperation performance and avoid breach of contract is not discussed.In this paper,a secure relay scheme is proposed based on the consortium blockchain system composed by different operators.In particular,smart contract checks the integrity of the message based on RSA accumulator,and executes transactions automatically when the message is delivered successfully.Detailed procedures are introduced for both uplink and downlink relay.Implementation based on Hyperledger Fabric proves the effectiveness of the proposed scheme and shows that the complexity of the scheme is low enough for practical deployment.

Secrecy Outage Probability for Two-Way Integrated Satellite Unmanned Aerial Vehicle Relay Networks with Hardware Impairments

In this paper,we investigate the secrecy outage performance for the two-way integrated satellite unmanned aerial vehicle relay networks with hardware impairments.Particularly,the closed-form expression for the secrecy outage probability is obtained.Moreover,to get more information on the secrecy outage probability in a high signalto-noise regime,the asymptotic analysis along with the secrecy diversity order and secrecy coding gain for the secrecy outage probability are also further obtained,which presents a fast method to evaluate the impact of system parameters and hardware impairments on the considered network.Finally,Monte Carlo simulation results are provided to show the efficiency of the theoretical analysis.

Selective PNC in Satellite-Terrestrial Network over Non-Identical Fading Channels

We analyze the performance of a twoway satellite-terrestrial decode-and-forward(DF) relay network over non-identical fading channels.In particular,selective physical-layer network coding(SPNC) is employed in the proposed network to improve the average end-to-end throughput performance.More specifically,by assuming that the DF relay performs instantaneous throughput comparisons before performing corresponding protocols,we derive the expressions of system instantaneous bit-error-rate(BER),instantaneous end-to-end throughput,average end-to-end throughput,single node detection(SND)occurrence probability and average end-to-end BER over non-identical fading channels.Finally,theoretical analyses and Monte Carlo simulation results are presented.Evaluations show that:1) SPNC protocol outperforms the conventional physical-layer network coding(PNC) protocol in infrequent light shadowing(ILS),average shadowing(AS) and frequent heavy shadowing(FHS) Shadowed-Rician fading channels.2) As the satellite-relay channel fading gets more sewere,SPNC protocol can achieve more performance improvement than PNC protocol and the occurrence probability of SND protocol increases progressively.3) The occurrence probability increase of SND has a beneficial effect on the average end-to-end throughput in low signal-to-noise ratio(SNR) regime,while the occurrence probability decrease of SND has a beneficial effect on the average end-to-end BER in highSNR regime.

Statistical QoS Provisioning Architecture for 6G Satellite-Terrestrial Integrated Networks

The emergence of massive ultra-reliable and low latency communications (mURLLC) as a category of age/time/reliability-sensitive service over 6G wireless networks has received considerable research attention, which has presented unprecedented challenges. As one of the key enablers for 6G,satellite-terrestrial integrated networks (STIN) have been developed to offer more expansive connectivity and comprehensive 3D coverage in space-aerial-terrestrial domains for supporting 6G mission-critical mURLLC applications while fulfilling diverse and rigorous quality of service (QoS) requirements. In the context of these mURLLC-driven satellite services, data freshness assumes paramount importance, as outdated data may engender unpredictable or catastrophic outcomes.To effectively measure data freshness in satellite-terrestrial integrated communications,age of information(AoI)has recently surfaced as a new dimension of QoS metric to support time-sensitive applications. It is crucial to design new analytical models that ensure stringent and diverse QoS metrics bounded by different key parameters,including AoI,delay,and reliability,over 6G satellite-terrestrial integrated networks. However,due to the complicated and dynamic nature of satellite-terrestrial integrated network environments, the research on efficiently defining new statistical QoS provisioning schemes while taking into account varying degrees of freedom has still been in their infancy. To remedy these deficiencies, in this paper we develop statistical QoS provisioning schemes over 6G satellite-terrestrial integrated networks in the finite blocklength regime. Particularly, we firstly introduce and review key technologies for supporting mURLLC.Secondly,we formulate a number of novel fundamental statistical-QoS metrics in the finite blocklength regime.Finally,we conduct a set of simulations to validate and evaluate our developed statistical QoS provisioning schemes over satellite-terrestrial 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.

继电保护数据库的统一建模新方法

以保护定值的在线校验和仿真为应用背景,详细叙述了继电保护数据库建模中遇到的主要技术难点和相应的解决方案。综合考虑了模型的通用性、维护工作量、数据库容量和访问效率等多个相关因素,力求达到保护数据建模的整体性能最优。对整个电网建立了完整统一的一次和二次设备模型。基于整个电网的统一模型,实现了面向实际成套保护装置的图形化建库和保护装置与相应一次设备的图形化关联。应用结果表明,该保护建模方法设计合理,具有良好的应用前景。

变电站自动化新技术的应用研究

在概述变电站自动化发展现状的基础上 ,指出面向对象的一体化设计模式和变电站自动化系统与数据通信网的通信是今后研究的主要课题。认为一体化设计有助于提高系统性能价格比 ,是今后发展的主要模式。计算机网络通信技术的应用将大大提高通信传输速率 ,满足电网能量管理系统(EMS)应用软件的数据实时性要求 。

变电站自动化新技术的应用研究

在概述变电站自动化发展现状的基础上，指出变电站自动化系统采用面向对象的一体化设计模式和采用数据通信网是今后研究的主要课题。一体化设计有助于提高系统性能价格比，是今后发展的主要模式。计算机网络通信技术的应用将大大提高通信传输速率，满足电网EMS应用软件的数据实时性要求，从根本上解决困扰多年的远动信息一发多收和转发问题。

天基为主的空间站测控通信模式

空间站时代为测控(TT&C)通信系统带来保障时间更长、覆盖要求更高、数据传输能力更强、航天员在轨工作生活体验更好等新的挑战,结合中继卫星系统(TDRSS)、卫星导航系统等天基测控通信手段的能力特点,提出以天基手段为主的解决方案,采用多星多舱段接力模式,将航天员出舱等重大活动的测控通信覆盖率提升至接近100%,采用多星多目标工作模式,较好地保障各种交会对接模式,综合利用中继卫星S频段多址(SMA)链路连续业务、短报文业务和北斗短报文业务常态化保障空间站安全运行,应用天地一体网络化技术,为航天员在轨上网、天地通信和载荷实验数据传输提供优质服务。

基于直流区域配电系统的网状网络

本文在综合电力系统的输电网络研究方面,分析了直流网状网络在舰船容量设置以及故障重构方面的优点,阐述了直流区域配电系统在隔离故障和优化舰船设计方面的优势。对于基于直流区域配电系统的直流网状网络,提出了此类网络在继电保护研究方向上主要的研究内容。

多用户认知协作无线网络中的中继选择与载波分配策略

在一个基于多载波的多主用户对-多次用户对-多认知中继节点组成的多用户认知协作无线网络中,本文考虑次用户网络采用underlay频谱接入模式与主用户网络共享频谱,次用户中继节点采用译码转发的信号处理方式,在满足主用户对干扰温度限制的条件下,研究如何通过中继选择和载波分配以最大化次用户对的信道容量和。该问题首先被建模成为一个带复杂约束的非凸整数规划问题。通过问题等价转化,本文把两个二维0-1系数矩阵的联合优化问题转化为一个三维0-1系数矩阵的优化问题,继而原问题转化为0-1线性规划问题。因为变量之间互相耦合的特性,常规优化算法无法求解此问题,基于分支定界框架,本文设计了中继选择与载波分配最优算法。仿真结果表明,该算法的复杂度远低于穷举法(平均迭代次数少于2.5次)且总能取到全局最优性能。

变电站微机保护通信故障及处理

针对变电站综合自动化系统现场实际运行中微机保护装置与监控系统通信的常见故障:站控层网络通信中断、保护装置误发软报文、保护状态量采集故障、35kV断路器遥控成功率低进行了分析,提出了处理措施。总结归纳了故障发生的原因:设备老化和不同设备厂家的通信接口兼容性问题。主要介绍了变电站微机保护装置通信的故障解决方法,为正确处理综自系统的此类故障提供了借鉴。

基于帧中继的综合业务网络的研究与开发

从网络结构、功能和协议出发，论述了以帧中继网络为基础，建立专用综合业务通 信网的实现机制，并分析了在开发中所要解决的主要技术问题．

建筑光伏接入配电网优化设计及工程案例

针对光伏发电以及配电网的特点,考虑电站接入规划设计、电能质量、继电保护、运行维护系统等方面的因素,提出了建筑光伏建设及其接入方案的优化设计方法。通过整体规划和设计,光伏电站能够可靠接入配电网,并安全稳定运行。提出对于配电网用户,在进行光伏电站接入评估时应重点关注电能质量及继电保护配置。通过具体的工程实例表明该方案在实际工程中得到了运用,效果较好。

远程连接在网络设计中的应用

本文从设计网络引入远程连接出发，介绍了几种不同的远程连接方案，对不同方案的原理进行分析、比较，说明了不同情况下方案的选择，并对运程连接的未来发展作了探讨。

变电站综合自动化系统设计

变电站综合自动化系统技术已经广泛应用于我国各电压等级的变电站的运行中。它采用先进的现场总线、保护装置、测控装置、计算机网络技术 ,利用数据库等软件工程 ,对变电站的各种模拟量、状态信息。