Nanosatellite-5G Integration in the Millimeter Wave Domain: A Full Top-Down Approach

This paper presents a novel network architecture for an integrated nanosatellite (nSAT)-5G system operating in the millimeter-wave (mmWave) domain. The architecture is realized adopting a delay/disruption tolerant networking (DTN) approach allowing end users to adopt standard devices. A buffer aware contact graph routing algorithm is designed to account for the buffer occupancy of the nSATs and for the connection planning derived from their visibility periods. At the terrestrial uplink, a coded random access is employed to realize a high-capacity interface for the typically irregular traffic of 5G users, while, at the space uplink, the DTN architecture is combined with the contention resolution diversity slotted Aloha protocol to match the recent update of the DVB-RCS2 standard. To achieve a reliable testing of the introduced functionalities, an accurate analysis of the statistic of the signal to interference-plus-noise ratio and of the capture probability at each mmWave link is developed by including interference, shadowing, fading, and noise. The application of the designed architecture to data transfer services in conjunction with possible delay reduction strategies, and an extension to inter-satellite communication, are finally presented by estimating the resulting loss/delay performance through a discrete-time discrete-event platform based on the integration of Matlab with Network Simulator 3

SatSel: A Satellite Selection Algorithm to reduce delivery time in DTN-Nanosatellite Networks for Internet Access in Rural Areas.

There 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

SatSel: A Satellite Selection Algorithm to reduce delivery time in DTN-Nanosatellite Networks for Internet Access in Rural Areas.

There 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

Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

Dtn and non-dtn routing protocols for inter-cubesat communications: A comprehensive survey

CubeSats, which are limited by size and mass, have limited functionality. These miniaturised satellites suffer from a low power budget, short radio range, low transmission speeds, and limited data storage capacity. Regardless of these limitations, CubeSats have been deployed to carry out many research missions, such as gravity mapping and the tracking of forest fires. One method of increasing their functionality and reducing their limitations is to form CubeSat networks, or swarms, where many CubeSats work together to carry out a mission. Nevertheless, the network might have intermittent connectivity and, accordingly, data communication becomes challenging in such a disjointed network where there is no contemporaneous path between source and destination due to satellites’ mobility pattern and given the limitations of range. In this survey, various inter-satellite routing protocols that are Delay Tolerant (DTN) and Non Delay Tolerant (Non-DTN) are considered. DTN routing protocols are considered for the scenarios where the network is disjointed with no contemporaneous path between a source and a destination. We qualitatively compare all of the above routing protocols to highlight the positive and negative points under different network constraints. We conclude that the performance of routing protocols used in aerospace communications is highly dependent on the evolving topology of the network over time. Additionally, the Non-DTN routing protocols will work efficiently if the network is dense enough to establish reliable links between CubeSats. Emphasis is also given to network capacity in terms of how buffer, energy, bandwidth, and contact duration influence the performance of DTN routing protocols, where, for example, flooding-based DTN protocols can provide superior performance in terms of maximizing delivery ratio and minimizing a delivery delay. However, such protocols are not suitable for CubeSat networks, as they harvest the limited resources of these tiny satellites and they are contrasted with forwarding-based DTN routing protocols, which are resource-friendly and produce minimum overheads on the cost of degraded delivery probability. From the literature, we found that quota-based DTN routing protocols can provide the necessary balance between delivery delay and overhead costs in many CubeSat missions

Antenna and Random Access Solutions for nano-satellite and 5G networks operating in the millimiter-wave domain

L\u2019obiettivo di questa tesi \ue8 la discussione di soluzioni per reti satellitari basate su nano-satelliti e reti 5G, operanti in onde millimetriche. I contributi originali di questo lavoro interessano due settori che ricoprono un ruolo chiave nel contesto delle comunicazioni digitali ad alta velocit\ue0 e alta capacit\ue0: i meccanismi di condivisione del mezzo trasmissivo basati sull\u2019accesso casuale e le antenne a schiera riconfigurabili e compatte. I risultati ottenuti in questi due ambiti sono poi applicati in un\u2019architettura di rete che integra sistemi 5G terrestri e una costellazione di nanosatelliti in orbita bassa. Le comunicazioni satellitari sono sempre pi\uf9 parte integrante della vita quotidiana. Negli ultimi anni, si \ue8 registrata una crescita notevole dei piccoli satelliti (da 1 a 100 kg), sia in termini di tecnologia, che di frequenza di utilizzo. Non solo vengono lanciati in gran numero, ma si \ue8 iniziato ad utilizzarli in costellazioni da diverse decine di unit\ue0. Questa attivit\ue0 \ue8 l\u2019indicatore di una prospettiva ormai prossima: gli sviluppi nel settore dell\u2019Information and Communication Technology hanno avviato diverse iniziative che puntano ad utilizzare megacostellazioni di satelliti come reti per la fornitura di servizi di comunicazione a banda larga. Lo sfruttamento delle onde millimetriche rappresenta quindi un punto cardine per soddisfare la crescente richiesta di capacit\ue0 dei sistemi radio di prossima generazione. Inoltre, lo scenario che ne risulta \ue8 tale da richiedere una connettivit\ue0 completa, cos\uec che ogni satellite operi come un nodo di rete a tutto tondo, con possibilit\ue0 di collegamento tra la terra e lo spazio, e da satellite a satellite. In tale contesto, il ricorso a moderne tecniche di accesso casuale \ue8 particolarmente indicato. Negli ultimi anni si \ue8 assistito a un rinnovato interesse per i protocolli di tipo Aloha, grazie alla possibilit\ue0 di dotare i ricevitori di sistemi di cancellazione dell\u2019interferenza. A tale proposito, viene presentato un nuovo algoritmo che affianca alla cancellazione iterativa di interferenza lo sfruttamento dell\u2019effetto cattura, tenendo al tempo stesso presente la possibile non idealit\ue0 della cancellazione, e quindi la presenza di un residuo. Le sue prestazioni sono confrontate con i metodi attualmente adottati negli standard, mostrando un miglioramento del throughput pari al 31%. Viene inoltre presentata la sintesi di un\u2019antenna a schiera operante in banda Ka adatta per l\u2019uso su nanosatelliti. La schiera risultante offre interessanti benefici in termini di larghezza di banda, polarizzazione e versatilit\ue0, essendo possibile un utilizzo dual-task (downlink verso terra e collegamentointersatellitare). I risultati cos\uec ottenuti sono poi utilizzati per dimostrare, in un simulatore tempo discreto ed evento discreto, le prestazioni ottenibili da un\u2019architettura di rete integrante segmenti di rete radiomobile 5G con una dorsale costituita da una costellazione di nanosatellti. Il simulatore si avvale inoltre di un modello teorico per valutare l\u2019impatto della distribuzione geometrica dei nodi interferenti su una comunicazione in onde millimetriche di tipo line-of-sight. Tale modello, validato con simulazioni di tipo Monte Carlo, contempla i diagrammi di radiazione delle antenne e i recenti modelli di canale in onde millimetriche, che tengono in considerazione rumore, dispersione angolare, fading e bounded path loss. Sono state ricavate delle formulazioni analitiche per la distribuzione della potenza di rumore e interferenza, che consentono di valutare in forma chiusa la probabilit\ue0 di cattura. Tale impostazione \ue8 stata infine usata per discutere gli effetti dell\u2019interferenza sulla capacit\ue0 di Shannon di un collegamento in uplink operante in onde millimetriche, prendendo in considerazione delle condizioni realistiche per il canale

Routing in the Space Internet: A contact graph routing tutorial

A Space Internet is possible, as long as the delay and disruption challenges imposed by the space environment are properly tackled. Because these conditions are not well addressed by terrestrial Internet, more capable Delay-Tolerant Networking (DTN) protocols and algorithms are being developed. In particular, the principles and techniques for routing among ground elements and spacecraft in near-Earth orbit and deep-space are enacted in the Contact Graph Routing (CGR) framework. CGR blends a set of non-trivial algorithm adaptations, space operations concepts, time-dynamic scheduling, and specific graph models. The complexity of that framework suggests a need for a focused discussion to facilitate its direct and correct apprehension. To this end, we present an in-depth tutorial that collects and organizes first-hand experience on researching, developing, implementing, and standardizing CGR. Content is laid out in a structure that considers the planning, route search and management, and forwarding phases bridging ground and space domains. We rely on intuitive graphical examples, supporting code material, and references to flight-grade CGR implementations details where pertinent. We hope this tutorial will serve as a valuable resource for engineers and that researchers can also apply the insights presented here to topics in DTN research.Fil: Fraire, Juan Andres. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Universitat Saarland; AlemaniaFil: De Jonckère, Olivier. Technische Universität Dresden; AlemaniaFil: Burleigh, Scott C.. California Institute of Technology; Estados Unido

Prediction-enhanced Routing in Disruption-tolerant Satellite Networks

This thesis introduces a framework for enhancing DTN (Delay-/Disruption-Tolerant Networking) routing in dynamic LEO satellite constellations based on the prediction of contacts. The solution is developed with a clear focus on the requirements imposed by the 'Ring Road' use case, mandating a concept for dynamic contact prediction and its integration into a state-of-the-art routing approach. The resulting system does not restrict possible applications to the 'Ring Road,' but allows for flexible adaptation to further use cases. A thorough evaluation shows that employing proactive routing in concert with a prediction mechanism offers significantly improved performance when compared to alternative opportunistic routing techniques

NGSO Constellation Design for Global Connectivity

Non-geostationary orbit (NGSO) satellite constellations represent a cornerstone in the NewSpace paradigm and thus have become one of the hottest topics for the industry, academia, but also for national space agencies and regulators. For instance, numerous companies worldwide, including Starlink, OneWeb, Kepler, SPUTNIX, and Amazon have started or will soon start to deploy their own NGSO constellations, which aim to provide either broadband or IoT services. One of the major drivers for such a high interest on NGSO constellations is that, with an appropriate design, they are capable of providing global coverage and connectivity.Comment: Book chapter submitted to IET Non-Geostationary Satellite Communications System