NOMA Empowered Energy Efficient Data Collection and Wireless Power Transfer in Space-Air-Ground Integrated Networks

As the sixth generation network(6G)emerges,the Internet of remote things(IoRT)has become a critical issue.However,conventional terrestrial networks cannot meet the delay-sensitive data collection needs of IoRT networks,and the Space-Air-Ground integrated network(SAGIN)holds promise.We propose a novel setup that integrates non-orthogonal multiple access(NOMA)and wireless power transfer(WPT)to collect latency-sensitive data from IoRT networks.To extend the lifetime of devices,we aim to minimize the maximum energy consumption among all IoRT devices.Due to the coupling between variables,the resulting problem is non-convex.We first decouple the variables and split the original problem into four subproblems.Then,we propose an iterative algorithm to solve the corresponding subproblems based on successive convex approximation(SCA)techniques and slack variables.Finally,simulation results show that the NOMA strategy has a tremendous advantage over the OMA scheme in terms of network lifetime and energy efficiency,providing valuable insights.

Holistic Service-Based Architecture for Space-Air-Ground Integrated Network for 5G-Advanced and Beyond

The Service-based Architecture(SBA) is one of the key innovations of 5G architecture that leverage modularized, self-contained and independent services to provide flexible and cloud-native 5G network. In this paper, SBA for Space-Air-Ground Integrated Network(SAGIN) is investigated to enable the 5G integration deployment. This paper proposes a novel Holistic Service-based Architecture(H-SBA)for SAGIN of 5G-Advanced and beyond, i.e., 6G. The H-SBA introduces the concept of end-to-end servicebased architecture design. The "Network Function Service", introduced in 5G SBA, is extended from Control Plane to User Plane, from core network to access network. Based on H-SBA, the new generation of protocol design is proposed, which proposes to use IETF QUIC and SRv6 to substitute 5G HTTP/2.0 and GTP-U. Testing results show that new protocols can achieve low latency and high throughput, making them promising candidate for H-SBA.

Service Customized Space-Air-Ground Integrated Network for Immersive Media: Architecture, Key Technologies, and Prospects

The space-air-ground integrated network(SAGIN) is regarded as the key approach to realize global coverage in future network and it reaches broad access for various services. Being the new paradigm of service, immersive media(IM) has attracted users’ attention for its virtualization, but it poses challenges to network performance, e.g. bandwidth, rate, latency. However, the SAGIN has limitations in supporting IM services, such as 4 K/8 K video, virtual reality, and interactive games. In this paper, a novel service customized SAGIN architecture for IM applications(SAG-IM) is proposed, which achieves content interactive and real-time communication among terminal users. State-of-the-art research is investigated in detail to facilitate the combination of SAGIN and service customized technology, which provides endto-end differentiated services for users. Besides, the functional components of SAG-IM contain the infrastructure layer, perception layer, intelligence layer, and application layer, reaching the capabilities of intelligent management of the network. Moreover, to provide IM content with ultra-high-definition and high frame rate for the optimal user experience, the promising key technologies on intelligent routing and delivery are discussed. The performance evaluation shows the superiority of SAG-IM in supporting IM service.Finally, the prospects in practical application are high-lighted.

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.

ESMD-Flow: An Intelligent Flow Forwarding Scheme with Endogenous Security Based on Mimic Defense in Space-Air-Ground Integrated Network

The Space-Air-Ground Integrated Network(SAGIN) realizes the integration of space, air,and ground networks, obtaining the global communication coverage.Software-Defined Networking(SDN) architecture in SAGIN has become a promising solution to guarantee the Quality of Service(QoS).However, the current routing algorithms mainly focus on the QoS of the service, rarely considering the security requirement of flow. To realize the secure transmission of flows in SAGIN, we propose an intelligent flow forwarding scheme with endogenous security based on Mimic Defense(ESMD-Flow). In this scheme, SDN controller will evaluate the reliability of nodes and links, isolate malicious nodes based on the reliability evaluation value, and adapt multipath routing strategy to ensure that flows are always forwarded along the most reliable multiple paths. In addition, in order to meet the security requirement of flows, we introduce the programming data plane to design a multiprotocol forwarding strategy for realizing the multiprotocol dynamic forwarding of flows. ESMD-Flow can reduce the network attack surface and improve the secure transmission capability of flows by implementing multipath routing and multi-protocol hybrid forwarding mechanism. The extensive simulations demonstrate that ESMD-Flow can significantly improve the average path reliability for routing and increase the difficulty of network eavesdropping while improving the network throughput and reducing the average packet delay.

Civil Aircraft Assisted Space-Air-Ground Integrated Networks: Architecture Design and Coverage Analysis

In this paper, we propose a novel AIenabled space-air-ground integrated networks(SAGIN). This new integrated networks architecture consists of LEO satellites and civil aircrafts carrying aerial base stations, called "civil aircraft assisted SAGIN(CAA-SAGIN)". The assistance of civil aircrafts can reduce the stress of satellite networks, improve the performance of SAGIN, decrease the construction cost and save space resources. Taking the Chinese mainland as an example, this paper has analyzed the distribution of civil aircrafts, and obtained the coverage characteristics of civil aircraft assisted networks(CAAN). Taking Starlink as the benchmark, this paper has calculated the service gap of CAAN, and designed the joint coverage constellation. The simulation results prove that the number of satellites in CAASAGIN can be greatly reduced with the assistance of civil aircrafts at the same data rate.

Three-Dimensional Cooperative Localization via Space-Air-Ground Integrated Networks

The space-air-ground integrated network(SAGIN)combines the superiority of the satellite,aerial,and ground communications,which is envisioned to provide high-precision positioning ability as well as seamless connectivity in the 5G and Beyond 5G(B5G)systems.In this paper,we propose a three-dimensional SAGIN localization scheme for ground agents utilizing multi-source information from satellites,base stations and unmanned aerial vehicles(UAVs).Based on the designed scheme,we derive the positioning performance bound and establish a distributed maximum likelihood algorithm to jointly estimate the positions and clock offsets of ground agents.Simulation results demonstrate the validity of the SAGIN localization scheme and reveal the effects of the number of satellites,the number of base stations,the number of UAVs and clock noise on positioning performance.

Intelligent Passive Detection of Aerial Target in Space-Air-Ground Integrated Networks

Passive detection of moving target is an important part of intelligent surveillance. Satellite has the potential to play a key role in many applications of space-air-ground integrated networks(SAGIN). In this paper, we propose a novel intelligent passive detection method for aerial target based on reservoir computing networks. Specifically, delayed feedback networks are utilized to refine the direct signals from the satellite in the reference channels. In addition, the satellite direct wave interference in the monitoring channels adopts adaptive interference suppression using the minimum mean square error filter. Furthermore, we employ decoupling echo state networks to predict the clutter interference in the monitoring channels and construct the detection statistics accordingly. Finally, a multilayer perceptron is adopted to detect the echo signal after interference suppression. Extensive simulations is conducted to evaluate the performance of our proposed method. Results show that the detection probability is almost 100% when the signal-to-interference ratio of echo signal is-36 dB, which demonstrates that our proposed method achieves efficient passive detection for aerial targets in typical SAGIN scenarios.

Software-Defined Space-Air-Ground Integrated Network Architecture with the Multi-Layer Satellite Backbone Network

Under the background of the rapid development of ground mobile communication,the advantages of high coverage,survivability,and flexibility of satellite communication provide air support to the construction of space information network.According to the requirements of the future space information communication,a software-defined Space-Air-Ground Integrated network architecture was proposed.It consisted of layered structure satellite backbone network,deep space communication network,the stratosphere communication network and the ground network.The Space-Air-Ground Integrated network was supported by the satellite backbone network.It provided data relay for the missions such as deep space exploration and controlled the deep-space spacecraft when needed.In addition,it safeguarded the anti-destructibility of stratospheric communication and assisted the stratosphere to supplement ground network communication.In this paper,algorithm requirements of the congestion control and routing of satellite backbone protocols for heterogeneous users’services were proposed.The algorithm requirements of distinguishing different service objects for the deep space communication and stratospheric communication network protocols were described.Considering the realistic demand for the dynamic coverage of the satellite backbone network and node cost,the multi-layer satellite backbone network architecture was constructed.On this basis,the proposed Software-defined Space-Air-Ground Integrated network architecture could be built as a large,scalable and efficient communication network that could be integrated into space,air,and ground.

Resource Allocation for Space-Air-Ground Integrated Networks:A Comprehensive Review

The space-air-ground integrated networks (SAGIN) has emerged as a critical paradigm to address the growing demands for global connectivity and enhanced communication services. This paper gives a thorough review of the strategies and methodologies for resource allocation within SAGIN, focusing on the challenges and solutions within its complex structure. With the advent of technologies such as 6G, the dynamics of resource optimization have become increasingly complex, necessitating innovative approaches for efficient management. We examine the application of mathematical optimization, game theory, artificial intelligence (AI), and dynamic optimization techniques in SAGIN,offering insights into their effectiveness in ensuring optimal resource distribution, minimizing delays, and maximizing network throughput and stability. The survey highlights the significant advances in AI-based methods,particularly deep learning and reinforcement learning, in tackling the inherent challenges of SAGIN resource allocation. Through a critical review of existing literature, this paper categorizes various resource allocation strategies, identifies current research gaps, and discusses potential future directions. Our findings highlight the crucial role of integrated and intelligent resource allocation mechanisms in realizing the full potential of SAGIN for next-generation communication networks.

A review of Space-Air-Ground integrated remote sensing techniques for atmospheric monitoring

Currently,the three-dimensional(3D)distribution and characteristics of air pollution cannot be understood based on the application of any single atmospheric monitoring technology.Long-term,high-precision and large-scale 3D atmospheric monitoring might become practical by combining heterogeneous modern technologies;for this purpose,the SpaceAir-Ground integrated system is a promising concept.In this system,optical remote sensing technologies employing fixed or mobile platforms are used as the main means for groundbased observations.Tethered balloons,unmanned aerial vehicles(UAV)and airborne platforms serve as the air-based observation segment.The final part,satellite remote sensing,corresponds to space-based observations.Aside from obtaining the 3D distribution of air pollution,research on emission estimation and pollution mechanisms has been extensively implemented based on the strengths of this system or some portion of it.Moreover,further research on the fusion of multi-source data,optimization of inversion algorithms,and coupling with atmospheric models is of great importance to the realization of this system.

卫星遥感水利应用进展与展望

监测感知数据是构建数字孪生水利体系的基础,卫星遥感是重要的监测感知手段。随着我国航天事业的蓬勃发展,依托国家科技重大专项、国家重点研发计划等科研项目开展技术攻关,以及国家防汛抗旱指挥系统工程等重大项目的推广应用,水利部构建了“采存算用全自主、遥感处理全链条、主要业务全覆盖、应用服务全贯通”的卫星遥感水利应用技术体系。卫星遥感技术在数字孪生水利数据底板建设、流域防洪、水资源管理与调配、河湖管理、水土保持、水利工程监测监管等业务工作中得到了广泛应用,发挥了显著成效。未来将从持续拓展卫星遥感影像资源、深度融合人工智能技术、强化“天空地”协同监测融合应用等方面,推动卫星遥感水利应用,赋能水利业务。

面向密集场景的空天地网络资源分配算法

空天地网络具有覆盖范围大、吞吐量高、弹性强等优点。该文针对大量用户并发接入、网络负载不均衡所引发的网络拥塞、服务质量恶化等问题,提出一种面向密集场景的资源分配算法。首先以用户需求为中心,根据不同类型用户任务的偏好来构建用户效用函数,然后基于匹配博弈的网络选择算法和结合对偶上升法的功率控制算法来实现负载均衡,优化资源分配方案。实验表明,相较于传统策略,所提策略整体用户接入率至少提高35%,时延和吞吐量方面性能提升超过50%;在密集场景下,能更有效地均衡负载,提升网络性能。

基于深度强化学习的空天地一体化网络资源分配算法

空天地一体化网络(SAGIN)通过提高地面网络的资源利用率可以有效满足多种业务类型的通信需求,然而忽略了系统的自适应能力和鲁棒性及不同用户的服务质量(QoS)。针对这一问题,该文提出在空天地一体化网络架构下,面向城区和郊区通信的深度强化学习(DRL)资源分配算法。基于第3代合作伙伴计划(3GPP)标准中定义的用户参考信号接收功率(RSRP),考虑地面同频干扰情况,以不同域中基站的时频资源作为约束条件,构建了最大化系统用户的下行吞吐量优化问题。利用深度Q网络(DQN)算法求解该优化问题时,定义了能够综合考虑用户服务质量需求、系统自适应能力及系统鲁棒性的奖励函数。仿真结果表明,综合考虑无人驾驶汽车,沉浸式服务及普通移动终端通信业务需求时,表征系统性能的奖励函数值在2 000次迭代下,相较于贪婪算法提升了39.1%;对于无人驾驶汽车业务,利用DQN算法进行资源分配后,相比于贪婪算法,丢包数平均下降38.07%,时延下降了6.05%。

铁路地质灾害勘察识别与监测预警

地质灾害对铁路建设、安全运营构成了极大威胁,“天空地”一体化综合勘察技术有效解决了地质灾害勘察识别难题。“天”基多源立体卫星遥感技术实现艰险复杂山区地质灾害的大范围精准判识,长时序InSAR与高精度GPS实现高陡岸坡的稳定性监测分析;“空”基真实感大场景、机载倾斜摄影和机载LiDAR扫描技术实现高植被覆盖区隐蔽性地质灾害判识;“地”基三维立体勘探技术获取岩土体结构、属性、参数;共同构建沟谷山地灾害链风险评价方案,为建设工程合理选址和工程设置提供依据。介绍地质灾害监测预警的方法、内容、技术和预警模型,对监测预警技术发展方向进行展望。

Space/Air Covert Communications:Potentials,Scenarios,and Key Technologies

Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. Aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface(RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation.

遥感技术在洪涝灾害防御中的前沿应用与面临挑战

及时全面掌握洪涝发生的关键信息是洪涝灾害防御的基础,将遥感技术与传统监测技术相结合,形成“天空地”一体化的立体监测体系,可以实现宏观观测与重点监测的互补与协同,有利于洪涝灾害的监测、预报和预警,显著提高洪涝灾害防御能力。遥感技术可应用于水体提取、水位测算、降水测量、流量估算、洪涝模拟、灾害损失估计等,但在监测数据可用性、监测方法有效性等方面还有很多问题需要解决。

基于赛博孪生的天空地智能网络架构与资源分配

随着海量移动和物联终端用户及其应用的爆发式涌现,迅速增加的网络流量对基于现有互联网架构设计的网络带来了严峻挑战。特别是对于空天网络,由于资源稀缺、时空分布不均,资源部署与需求不匹配,网络性能亟需优化提升。为解决以上问题,本文构建了基于赛博孪生的天空地智能网络体系架构。该架构通过软件定义网络和资源虚拟化将物理资源抽象为虚拟资源,并采用边缘云技术将赛博孪生内生于网络边缘侧,使得网络更加灵活、具有更强的扩展性、更高的安全性。同时,本文利用匹配理论将资源分配问题转化为多参数、多玩家的匹配博弈问题,通过构建匹配模型并求解效用函数,提出了高效稳定的三边匹配算法,实现了资源分配的整体性能最优。仿真结果表明,本文方法可有效提升网络性能,实现资源的高效分配。

卫星互联网赋能新型电力系统创新应用

卫星互联网是通过卫星规模化组网,以航天、通信、网络、数据等技术为支撑的全球全域全时新型网络信息基础设施。与传统卫星网络相比,具有广覆盖、低时延、高带宽、低成本等优势。通过剖析新型电力系统在广域覆盖、抗毁顽存、垂直应用等信息化能力建设方面的挑战,凝练高中低轨协同的卫星互联网内涵定义与能力特征,提出卫星互联网在电力规划、态势感知、巡视检修、防灾应急等业务领域赋能新型电力系统的实践路径。提出基于零信任的星地融合网络信息安全体系,为建设、运行及发展空天地全面一体、通导遥深度融合的新型电力系统提供基础参考,进一步提升新质生产力水平。

无人机辅助智能边缘网络技术综述

简要介绍了无人机作为空基信息平台的主要应用场景,结合6G多接入网络和用户为中心网络架构,讨论了无人机在构建智能边缘网络中的重要作用。结合无人机平台在不同场景下的通、感、算能力特点,介绍无人机自组网、无人机通感一体化、无人机边缘计算等无人机辅助智能边缘网络关键技术。最后,围绕无人机在构建智能边缘网络过程中与无线接入网新技术结合时产生的新问题,探讨无人机通信信道建模、三维立体部署与路径规划、携能有限与续航问题、无人机网络安全、无人机集群异构网络融合等关键技术挑战和未来研究方向。