1,721,025 research outputs found
E-CGR: Energy-aware Contact Graph Routing over Nanosatellite Networks
No full textSatellite constellations are envisioned as meaningful transport networks to forward data throughout the world, both as a solution for areas where there are no other telecommunication infrastructures or as a backup solution to support the terrestrial network. Low Earth Orbit (LEO) satellites are the most appealing for this purpose due to the achievable performance keeping low design and deployment costs. Mega-constellation made of thousands of small LEO satellites are planned to be employed to cover the entire Earth's surface. However, smaller is the size and weight of satellites, higher are the technological challenges and stricter are the hardware constraints which affect the data forwarding process and have to be taken into account. Energy is one of them. Telecommunication hardware energy consumption is considerable, especially in case of high traffic volumes, while energy storage capacity and battery recharge rate are limited due to the small battery size and solar panel surface area, respectively. In this paper, we propose a novel energy-aware routing algorithm based on the Contact Graph Routing (CGR) called E-CGR. E-CGR exploits static and known a priori information about contacts to compute routing paths from sources to destinations which are then "validated" and "confirmed" from the energy viewpoint
SatSel: A Satellite Selection Algorithm to reduce delivery time in DTN-Nanosatellite Networks for Internet Access in Rural Areas.
No full textThere are some different ways to connect rural areas to the Internet. One of these provides the use of a nanosatellite constellation. This type of network allows people in rural areas to enjoy all services the Internet can offer keeping low the cost of Internet access. One of the critical aspect is related to the delivery time, because LEO satellite links are not always up. This means that the system must be able to deal with periodic disruptions and high delays in the path from the source to the destination, considering that data could be stored in nanosatellite, Internet gateway (also called hot spot), and rural gateway (also called cold spot) buffers also for several seconds or minutes waiting to be forwarded. In the path from rural areas to the Internet, it is possible to reduce data delivery time acting on rural gateways. We propose SatSel: a selection algorithm which allows the cold spots to choose the nanosatellite to whom upload data in order to reduce the data delivery tim
A Source Routing Algorithm Based on CGR for DTN-Nanosatellite Networks
No full textThe number of nanosatellites orbiting around the Earth is increasing year after year. Nanosatellite constellations can be deployed to cover even larger areas. However, data exchange among nanosatellites is not trivial, especially due to the required hardware components related to the limited size and
weight. Moreover, in some cases, contacts between nanosatellites and ground stations cannot always be guaranteed. The Delay and Disruption Tolerant Networking (DTN) paradigm allows storing data in nanosatellite and ground station buffers until the contact with the next hop is available. Routing in this kind of network is a crucial aspect. Delivery times are larger compared to a “classical” network due to the time that data have to wait inside intermediate node buffers and to the limitation of available resources, especially on-board nanosatellites. The adoption of a smart routing strategy can contribute relieving this gap. In this paper, we propose S-CGR, a Source routing algorithm based on the Contact Graph Routing (CGR). It computes a routing path
from source to destination nodes for each bundle, which is the data unit in DTN networks. S-CGR considers static and known a priori information about contacts (begin times, end times, and overall contact volumes) and dynamic information about nanosatellite buffer occupancies and available contact volumes. The complete source/destination paths are stored in the bundles. Intermediate nodes read the routin
Advanced Constellation Emulation and Synthetic Datasets Generation for Non-Terrestrial Networks
No full textMega satellite constellations, now realized entities, encompass thousands of nodes. However, efficient orchestration of multi-hop paths and distributed processing tasks in Non-Terrestrial Networks (NTN) remains a considerable challenge. The integration of NTN systems into 5G cellular networks necessitates innovative adaptations of Software-Defined Networking (SDN) and Multi-access Edge Computing (MEC) to suit the dynamic environments of NTN. In this context, we present MeteorNet, a state-of-the-art emulation tool conceived for satellite constellations. MeteorNet accurately replicates the behavior of NTNs by implementing space orbits, Earth rotation calculations, and Linux network interfaces across diverse network layers. Coupled with a continuous measurement system founded on sFlow, MeteorNet compiles critical switch variables in a centralized database, thus providing a distinctive methodology for creating realistic synthetic datasets. The pertinence of synthetic datasets is paramount in NTN, given the scarcity of operative systems and the inaccessibility of accurate data from the few existing systems due to proprietary constraints. These datasets are instrumental for formulating and training intelligent control algorithms and Machine Learning (ML) models for SDN and MEC advancements in NTN. To illustrate the efficacy of this approach, we explore a realistic networking case study with a ring topology, demonstrating how data models describe intricate routing and edge computing protocols for NTN
An SDR-Based Framework for Cybersecurity Assessment of Vehicle-to-Everything (V2X) Systems
No full textIn the realm of Vehicle-to-Everything systems and vehicular ad-hoc networks, unique characteristics such as high data speeds and bandwidth requirements distinguish them from conventional wireless technologies. Effective transmission and reception of critical Cooperative Awareness Messages and safety data necessitate advanced hardware and software capable of handling substantial message volumes efficiently. This makes it difficult to assess the vulnerabilities of the system, in particular for non-proprietary parties. For this purpose, with a particular focus on wireless communication channels, a framework based on Software Defined Radio technology is presented to assess vulnerabilities and evaluate the profound security of Vehicle-to-Everything network communications between On Board Unit and Road Side Unit for implications of unauthorized interception and manipulation of vital vehicle data by individuals situated near highways. The paper raises pertinent questions about the security level of Vehicle-to-Everything communications and focuses on the importance of robust cybersecurity measures in safeguarding Vehicle-to-Everything systems against potential threats and ensuring the integrity and safety of vehicular communication channels
On the Latency Trade-off Between Space and Terrestrial Clouds in Non-Terrestrial Networks
No full textNon-Terrestrial Networks (NTN) are poised to revolutionize 5G and 6G networks by integrating terrestrial and space-based cloud systems, enabling dynamic task allocation for optimal performance. Despite their promise, understanding the trade-offs between terrestrial and non-terrestrial edge computing architectures remains an area for improvement. This paper presents a comprehensive latency-focused trade-off analysis using a novel real-time emulation platform that accurately models terrestrial and space cloud environments. By evaluating network latency across geodesic distances from a fixed ground gateway, we delineate scenarios where terrestrial clouds excel and identify conditions under which Space Cloud architectures surpass their terrestrial counterparts. Additionally, we analyze how server placement strategies in satellite constellations impact performance, revealing the critical interplay between server distribution and latency outcomes. These findings offer actionable insights for designing and operating hybrid cloud systems, emphasizing the need for tailored architectures to maximize the potential of NTN-based edge computing
Fuzzy Logic-Based Orchestration of Multi-Access Edge Computing in LEO Satellite Constellations
No full textIn the fast-evolving domain of satellite communications, massive constellations of LEO satellites are increasingly gaining notice in both academic and industrial sectors. Operating these growing constellations has become a complex challenge, and new obstacles have emerged with integrating cellular networks in the space sector. Some techniques like Multi-access Edge Computing (MEC) were initially designed for static terrestrial networks and should be adapted to the dynamic nature of Non-Terrestrial Networks (NTN). This study introduces an innovative Fuzzy Logic-based controller tailored explicitly for determining the operational status of satellite MEC servers based on historical task loads and task processing failures. Our approach is grounded in a distributed control framework, where each satellite node operates autonomously relying on its own data and limited information from neighboring nodes. We evaluated our fuzzy controller against a baseline strategy, demonstrating significant improvements in reducing the overall active time of MEC nodes. The orchestration effectiveness of these strategies was tested by using our custom-built continuous time emulation framework for satellite constellations. This framework integrates 1) the Simplified General Perturbations Model 4 (SGP4) for orbit propagation, 2) Mininet for network virtualization, 3) Docker for operating system virtualization, and 4) MEC task offloading and orchestration
From Emerging LEO Satellite Constellations to the Space Cloud: Emulation Platforms and Orchestration Methods
No full textIn the rapidly advancing field of satellite communications, mega-constellations of Low Earth Orbit (LEO) satellites are gaining significant attention from the academic and industrial sectors. Managing these expanding constellations has become increasingly complex, and integrating them with classical cellular networks presents new automation challenges. We envision a Space Cloud in which Multiaccess Edge Computing (MEC) services are deployed within cross-liked space networks to address emerging Non-Terrestrial Networks (NTNs) latency demands. Integrating computation services in orbit will be instrumental in unlocking a Space Cloud that reduces the need to route computation requests to the Internet backbone. This study’s first contribution is MeteorNet, an open-source constellation and edge computing emulation platform aimed at assessing the expected performance of future Space Clouds. MeteorNet realistically replicates the behavior of edge computing in a synthetic satellite constellation network hosting onboard containerized servers. The second contribution comprises two innovative edge orchestration strategies based on fuzzy logic and reinforcement learning.
These strategies leverage historical data on task loads and processing failures to control the activation of on-orbit edge servers, ensuring efficient resource utilization. A Pareto-efficient analysis of multiple Key Performance Indicators (KPIs) using MeteorNet proves the approach’s feasibility in space missions with energy constraints and limited computation resources
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