In the evolving landscape of satellite communications, the deployment of Low-Earth Orbit (LEO) satellite constellations promises to revolutionize global Internet access by providing low-latency, high-bandwidth connectivity to underserved regions. However, the dynamic nature of LEO satellite networks, characterized by rapid orbital movement and frequent changes in Inter-Satellite Links (ISLs), challenges the suitability of existing Internet protocols designed for static terrestrial infrastructures. Testing and developing new solutions and protocols on actual satellite mega-constellations are either too expensive or impractical because some of these constellations are not fully deployed yet. This creates the need for a realistic simulation platform that can accurately simulate this large scale of satellites, and allow end-to-end control over all aspects of LEO constellations. This paper introduces xeoverse, a scalable and realistic network simulator designed to support comprehensive LEO satellite network research and experimentation. By modeling user terminals, satellites, and ground stations as lightweight Linux virtual machines within Mininet and implementing three key strategies -- pre-computing topology and routing changes, updating only changing ISL links, and focusing on ISL links relevant to the simulation scenario -- xeoverse achieves real-time simulation, where 1 simulated second equals 1 wall-clock second. Our evaluations show that xeoverse outperforms state-of-the-art simulators Hypatia and StarryNet in terms of total simulation time by being 2.9 and 40 times faster, respectively.
The integration of satellite and terrestrial networks is a promising solution for extending broadband coverage to areas not connected to a terrestrial infrastructure, as also demonstrated by recent commercial and standardisation endeavours. However, the large delays and Doppler shifts over the satellite channel pose severe technical challenges to traditional terrestrial systems, as LTE or 5G. In this paper, two architectures are proposed for a LEO mega-constellation realising a satellite-enabled LTE system, in which the on- ground LTE entity is either an eNB (Sat-eNB) or a Relay Node (Sat-RN).…
The design and launch of large-scale satellite networks create an imminent demand for efficient and delay-minimising routing methods. With the rising number of satellites in such constellations, pre-computing all shortest routes between all satellites and for all times becomes more and more infeasible due to space and time limitations. Even though distributed on-demand routing methods were developed for specific LEO satellite network configurations, they are not suited for increasingly popular mega-constellations based on Walker Delta formations. The contributions of this paper are twofold. Fi…
Fluid-Dynamic Interference Modeling for LEO Mega-Constellations: A Spatiotemporal Kinetic Field Approach
Future Technology Research Center, China Telecom Research Institute（中国电信研究院未来技术研究中心）；School of Information and Communication Engineering, Beijing University of Posts and Telecommunications（北京邮电大学信息与通信工程学院）；Cloud Network Operating System R&D Center, China Telecom（中国电信云网操作系统研发中心）；School of Electronics and Computer Science, University of Southampton（南安普顿大学电子与计算机科学学院）
We present F-Rosette, a stable space-ground network structure for low-earth orbit (LEO) satellite mega-constellations at scale. Due to the dynamic many-to-many space-ground mapping in high mobility, existing LEO mega-constellations with IP protocol stack suffer from frequent user IP address changes (every 133~510s per user) and network routing re-convergence (<20% network usability). To provably stabilize the space-ground network under high mobility and many-to-many dynamics, F-Rosette adopts a recursive structure over the Rosette constellation, derives a hierarchical and time-invariant networ…
As emerging massive constellations are intended to provide seamless connectivity for remote areas using hundreds of small low Earth orbit (LEO) satellites, new methodologies have great importance to study the performance of these networks. In this paper, we derive both downlink and uplink analytical expressions for coverage probability and data rate of an inclined LEO constellation under general fading, regardless of exact satellites' positions. Our solution involves two phases as we, first, abstract the network into a uniformly distributed network. Secondly, we obtain a new parameter, effecti…
Low earth orbit (LEO) mega-constellations, integrating government space systems and commercial practices, have emerged as enabling technologies for the sixth generation (6G) networks due to their good merits of global coverage and ubiquitous services for military and civilian use cases. However, convergent LEO-based satellite networking infrastructures still lack leveraging the synergy of space and terrestrial systems. This paper, therefore, extends conventional serverless cloud platforms with serverless edge learning architectures for 6G proliferated LEO (p-LEO) satellite ecosystems and provi…
Offering space-based Internet services with mega-constellations of low Earth orbit (LEO) satellites is a promising solution to connecting the unconnected. It can complement the coverage of terrestrial networks to help bridge the digital divide. However, there are challenges from operational obstacles to technical hurdles facing the development of LEO satellite access. This article provides an overview of state of the art in LEO satellite access, including the evolution of LEO satellite constellations and capabilities, critical technical challenges and solutions, standardization aspects from 5G…
Low Earth Orbit (LEO) Satellite Network (SatNet) with their mega-constellations are expected to play a key role in providing ubiquitous Internet and communications services in the future. LEO SatNets will provide wide-area coverage and support service availability, continuity, and scalability. To support the integration of SatNets and terrestrial Fifth Generation (5G)networks and beyond, the satellite communication industry has become increasingly involved with the 3rd Generation Partnership Project (3GPP) standardization activities for 5G. In this work, we review the 3GPP standardization acti…
With the proliferated low-Earth-orbit (LEO) satellites in mega-constellations, the future Internet will be able to reach any place on Earth, providing high-quality services to everyone. However, high-quality operations in terms of timeliness and resilience are lacking in the current solutions. This paper proposes a multi-layer networking approach called "Cross-Layer Descent (CLD)". Based on the proposed system model, principles, and measures, CLD can support foundational services such as telecommand (TC) transmissions for various network operation missions for LEO satellites compliant with the…
Low Earth orbit (LEO) satellite networks (SatNets) are envisioned to play a crucial role in providing global and ubiquitous connectivity efficiently. Accordingly, in the coming years, thousands of LEO satellites will be launched to create ultradense LEO mega-constellations, and the Third Generation Partnership Project (3GPP) is working on evolving fifth-generation (5G) systems to support such non-terrestrial networks (NTN). However, many challenges are associated with the deployment of LEOs from communications and networking perspectives. In this paper, we propose a novel cell-free massive mul…
The ultra-dense deployment of interconnected satellites will characterize future low Earth orbit (LEO) mega-constellations. Exploiting this towards a more efficient satellite network (SatNet), this paper proposes a novel LEO SatNet architecture based on distributed massive multiple-input multiple-output (DM-MIMO) technology allowing ground user terminals to be connected to a cluster of satellites. To this end, we investigate various aspects of DM-MIMO-based satellite network design, the benefits of using this architecture, the associated challenges, and the potential solutions. In addition, we…
Korea University（高丽大学）；Deakin University（迪肯大学）；University of Oulu（奥卢大学）
A mega-constellation of low-earth orbit (LEO) satellites has the potential to enable long-range communication with low latency. Integrating this with burgeoning unmanned aerial vehicle (UAV) assisted non-terrestrial networks will be a disruptive solution for beyond 5G systems provisioning large scale three-dimensional connectivity. In this article, we study the problem of forwarding packets between two faraway ground terminals, through an LEO satellite selected from an orbiting constellation and a mobile high-altitude platform (HAP) such as a fixed-wing UAV. To maximize the end-to-end data rat…
Korea University（高丽大学）；University of Oulu（奥卢大学）；Deakin University（迪肯大学）
A mega-constellation of low-altitude earth orbit (LEO) satellites (SATs) and burgeoning unmanned aerial vehicles (UAVs) are promising enablers for high-speed and long-distance communications in beyond fifth-generation (5G) systems. Integrating SATs and UAVs within a non-terrestrial network (NTN), in this article we investigate the problem of forwarding packets between two faraway ground terminals through SAT and UAV relays using either millimeter-wave (mmWave) radio-frequency (RF) or free-space optical (FSO) link. Towards maximizing the communication efficiency, the real-time associations with…
Towards Federated, Green, and Resilient 6G Non-Terrestrial Networks
Iowa State University（爱荷华州立大学）；iABG；Department of Communications & Computer Engineering, University of Malta（马耳他大学通信与计算机工程系）；Indian Institute of Space Science and Technology（印度空间科学与技术学院）；German Aerospace Center (DLR)（德国航空航天中心）；DITEN-University of Genoa / CNIT National Laboratory of Smart and Secure Networks (S2N)（热那亚大学DITEN / CNIT智能与安全网络国家实验室）；Johns Hopkins University（约翰斯·霍普金斯大学）；Independent Consultant, Santa Clara, CA, USA（独立顾问）；Quantum Dimension, Inc.（量子维度公司）；Department of Information Engineering and Mathematics, University of Siena（锡耶纳大学信息与工程数学系）；Centre for Quantum Engineering, Research and Education, TCG Crest（TCG Crest量子工程研究教育中心）；IEEE MTT-S（IEEE微波理论与技术学会）；École de technologie supérieure（高等技术学院）；Texas A&M University（德克萨斯农工大学）；Hewlett Packard Enterprise（惠普企业）；BITS Pilani, Hyderabad Campus（巴伊拉特理工学院皮拉尼校区海德拉巴分校）；University of Surrey（萨里大学）；Department of Information Engineering, University of Florence（佛罗伦萨大学信息工程系）
Recent breakthroughs in technology have led to a thriving "new space" culture in low-Earth orbit (LEO) in which performance and cost considerations dominate over resilience and reliability as mission goals. These advances create a manifold of opportunities for new research and business models but come with a number of striking new challenges. In particular, the size and weight limitations of low-Earth orbit small satellites make their successful operation rest on a fine balance between solar power infeed and the power demands of the mission payload and supporting platform technologies, buffere…
