Integrating LEO Satellite Constellations into Internet Backbone

Low Earth Orbit (LEO) satellite constellations have been used for ubiquitous and flexible Internet access services. However, a number of problems related to the integration of terrestrial with satellite hosts should be resolved for the effective exploitation of LEO constellations. LEO constellations are different from terrestrial Internet because of its special properties, which result in a lot of problems. A key issue is how to route Internet packets to the LEO constellation. In the thesis (1) the background of LEO constellations was introduced; (2) the obstacles of routing between the satellites and Internet were outlined; (3) The particular problem, which must be solved, is the routing burst stream traffic in LEO satellite constellations. Two novel routing algorithmsCControl Route Transmission (CRT) and CRT with bandwidth allocation (BCRT)Cwere utilized to address the bursts routing problem. CRT is an adaptive protocol which is able to minimize the congestion in the constellations. BCRT is a CRT extension which is allowed to class the traffic (e.g. video) with different QoS requirements and guarantees. Both of CRT and BCRT work in time epochs. Routes are computed on the basis of a directed weighted graph representing the global traffic traveling in the constellations. Both CRT and BCRT were evaluated via simulation and compared with other proposals in the literatures. The results showed that CRT is a simple algorithm, but the strategy produced by CRT could avoid the congestion and enhance the global resource usage in different traffic conditions. Moreover, the explicit reservation and reroute of BCRT greatly improve the performance of CRT. In particular, the dropping rate of BCRT is very low and the average delivery time is comparable with other proposals in the literatures.Low Earth Orbit (LEO) satellite constellations have been used for ubiquitous and flexible Internet access services. However, a number of problems related to the integration of terrestrial with satellite hosts should be resolved for the effective exploitation of LEO constellations. LEO constellations are different from terrestrial Internet because of its special properties, which result in a lot of problems. A key issue is how to route Internet packets to the LEO constellation. In the thesis (1) the background of LEO constellations was introduced; (2) the obstacles of routing between the satellites and Internet were outlined; (3) The particular problem, which must be solved, is the routing burst stream traffic in LEO satellite constellations. Two novel routing algorithmsCControl Route Transmission (CRT) and CRT with bandwidth allocation (BCRT)Cwere utilized to address the bursts routing problem. CRT is an adaptive protocol which is able to minimize the congestion in the constellations. BCRT is a CRT extension which is allowed to class the traffic (e.g. video) with different QoS requirements and guarantees. Both of CRT and BCRT work in time epochs. Routes are computed on the basis of a directed weighted graph representing the global traffic traveling in the constellations. Both CRT and BCRT were evaluated via simulation and compared with other proposals in the literatures. The results showed that CRT is a simple algorithm, but the strategy produced by CRT could avoid the congestion and enhance the global resource usage in different traffic conditions. Moreover, the explicit reservation and reroute of BCRT greatly improve the performance of CRT. In particular, the dropping rate of BCRT is very low and the average delivery time is comparable with other proposals in the literatures

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Energy efficiency in LEO satellite and terrestrial wired environments

To meet an ever-growing demand for advanced multimedia services and to support electronic connectivity anywhere on the planet, development of ubiquitous broadband multimedia systems is gaining a huge interest at both academic and industry levels. Satellite networks in general and LEO satellite constellations in particular will play an essential role in the deployment of such systems. Therefore, as LEO satellite constellations like Iridium or IridiumNEXT are extremely expensive to deploy and maintain, extending their service lifetimes is of crucial importance. In the main part of this thesis, we propose different techniques for extending satellite service life in LEO satellite constellations. Satellites in such constellations can spend over 30% of their time under the earth’s umbra, time during which they are powered by batteries. While the batteries are recharged by solar energy, the Depth of Discharge (DoD) they reach during eclipse significantly affects their lifetime – and by extension, the service life of the satellites themselves. For batteries of the type that power Iridium and Iridium-NEXT satellites, a 15% increase to the DoD can practically cut their service lives in half. We first focus on routing and propose two new routing metrics – LASER and SLIM – that try to strike a balance between performance and battery DoD in LEO satellite constellations. Our basic approach is to leverage the deterministic movement of satellites for favoring routing traffic over satellites exposed to the sun as opposed to the eclipsed satellites, thereby decreasing the average battery DoD– all without taking a significant penalty in performance. Then, we deal with resource consolidation – a new paradigm for the reduction of the power consumption. It consists in having a carefully selected subset of network links entering a sleep state, and use the rest to transport the required amount of traffic. This possible without causing major disruptions to network activities. Since communication networks are designed over the peak traffic periods, and with redundancy and over-provisioned in mind. As a remedy to these issues, we propose two different methods to perform resource consolidation in LEO networks. First, we propose trafficaware metric for quantifiying the quality of a frugal topology, the Maximum Link Utilization (MLU). With the problem being NP-hard subject to a given MLU threshold, we introduce two heuristics, BASIC and SNAP, which represent different tradeoffs in terms of performance and simplicity. Second, we propose a new lightweight traffic-agnostic metric for quantifiying the quality of a frugal topology, the Adequacy Index (ADI). After showing that the problem of minimizing the power consumption of a LEO network subject to a given ADI threshold is NP-hard, we propose a heuristc named AvOId to solve it. We evaluate both forms of resource consolidation using realistic LEO topologies and traffic requests. The results show that the simple schemes we develop are almost double the satellite batteries lifetime. Following the green networking in LEO systems, the second part of this thesis focuses on extending the resource consolidation schemes to current wired networks. Indeed, the energy consumption of wired networks has been traditionally overlooked. Several studies exhibit that the traffic load of the routers only has a small influence on their energy consumption. Hence, the power consumption in networks is strongly related to the number of active network elements. In this context, we extend the traffic-agnostic metric, ADI, to the wired networks. We model the problem subject to ADI threshold as NP-hard. Then, we propose two polynomial time heuristics – ABStAIn and CuTBAck. Although ABStAIn and CuTBAck are traffic unaware, we assess their behavior under real traffic loads from 3 networks, demonstrating that their performance are comparable to the more complex traffic-aware solutions proposed in the literature

Towards 6G Through SDN and NFV-Based Solutions for Terrestrial and Non-Terrestrial Networks

As societal needs continue to evolve, there has been a marked rise in a wide variety of emerging use cases that cannot be served adequately by existing networks. For example, increasing industrial automation has not only resulted in a massive rise in the number of connected devices, but has also brought forth the need for remote monitoring and reconnaissance at scale, often in remote locations characterized by a lack of connectivity options. Going beyond 5G, which has largely focused on enhancing the quality-of-experience for end devices, the next generation of wireless communications is expected to be centered around the idea of "wireless ubiquity". The concept of wireless ubiquity mandates that the quality of connectivity is not only determined by classical metrics such as throughput, reliability, and latency, but also by the level of coverage offered by the network. In other words, the upcoming sixth generation of wireless communications should be characterized by networks that exhibit high throughput and reliability with low latency, while also providing robust connectivity to a multitude of devices spread across the surface of the Earth, without any geographical constraints. The objective of this PhD thesis is to design novel architectural solutions for the upcoming sixth generation of cellular and space communications systems with a view to enabling wireless ubiquity with software-defined networking and network function virtualization at its core. Towards this goal, this thesis introduces a novel end-to-end system architecture for cellular communications characterized by innovations such as the AirHYPE wireless hypervisor. Furthermore, within the cellular systems domain, solutions for radio access network design with software-defined mobility management, and containerized core network design optimization have also been presented. On the other hand, within the space systems domain, this thesis introduces the concept of the Internet of Space Things (IoST). IoST is a novel cyber-physical system centered on nanosatellites and is capable of delivering ubiquitous connectivity for a wide variety of use cases, ranging from monitoring and reconnaissance to in-space backhauling. In this direction, contributions relating to constellation design, routing, and automatic network slicing form a key aspect of this thesis.Ph.D

Σχεδιασμός Τηλεπικοινωνιακού Δικτύου και Ανάλυση της Δρομολόγησης σε έναν Αστερισμό Δορυφόρων

Το αντικείμενο, το οποίο μελετάται στην εργασία αυτή είναι τα δορυφορικά συστήματα επικοινωνιών και οι τεχνικές δρομολόγησης σε αυτά. Σκοπός είναι να εντοπίσουμε τα χαρακτηριστικά εκείνα που επηρεάζουν τον σχεδιασμό ενός δορυφορικού δικτύου και τον τρόπο με τον οποίο αυτές οι παράμετροι συσχετίζονται. Ένας ακόμη στόχος της εργασίας αυτής είναι να εξετάσει το κατά πόσο η χρήση IP δρομολόγησης μπορεί να χρησιμοποιηθεί σε δορυφορικά δίκτυα εξίσου αποδοτικά με τη χρήση IP στο επίγειο Διαδίκτυο, καθώς και κάτω από ποιες συνθήκες ή με τη χρήση ποιών εναλλακτικών τεχνικών. Στη συνέχεια ακολουθεί περιγραφή των θεμάτων που καλύπτονται σε κάθε ένα από τα κεφάλαια της εργασίας. Στο 1ο κεφάλαιο γίνεται αρχικά μία ιστορική αναδρομή των δορυφόρων και των υπηρεσιών που παρέχουν οι δορυφορικοί αστερισμοί. Ακολουθεί εισαγωγή στο αντικείμενο των δορυφορικών συστημάτων μέσω της παρουσίασης εννοιών όπως σχηματισμός αστερισμού, μονοπατιού και συμπλέγματος. Επίσης γίνεται καταγραφή των επιλογών που υπάρχουν για έναν δορυφόρο όσο αναφορά τον τύπο της τροχιάς και το υψόμετρο. Το κεφάλαιο 2 επικεντρώνεται στα βασικά χαρακτηριστικά ενός δικτύου που σχηματίζεται από τον αστερισμό δορυφόρων. Κυρίως δίνεται έμφαση στην τοπολογία και τις συνδέσεις μεταξύ των δορυφόρων, στην καθυστέρηση, στην κινητικότητα και τη μοντελοποίησή της, καθώς και στη διαδικασία της μεταπομπής. Στο κεφάλαιο 3 μελετούμε τον τρόπο σχεδιασμού του δικτύου ενός αστερισμού δορυφόρων και τις παραμέτρους που πρέπει να εξεταστούν για να δημιουργηθεί ένα λειτουργικό και βιώσιμο δίκτυο. Αρχικά τίθενται 8 σχεδιαστικοί στόχοι για το δορυφορικό δίκτυο που σχετίζονται με την ποιότητα των υπηρεσιών που επιθυμούμε και στη συνέχεια αναλύονται οι παράμετροι του δικτύου που μπορούν να επηρεάσουν αυτούς τους 8 στόχους. Οι παράμετροι που εξετάστηκαν αφορούν την δομή του αστερισμού, τον τύπο της τροχιάς, το υψόμετρο των δορυφόρων καθώς και το πλήθος τόσο των τροχιών όσο και των δορυφόρων. Τα αποτελέσματα αυτής της ανάλυσης οδήγησαν στις τιμές κάποιων παραμέτρων του δικτύου οι οποίες χρησιμοποιήθηκαν για την προσομοίωση του συγκεκριμένου σχεδιασμού. Στο 4ο κεφάλαιο εξετάζεται η χρήση της IP δρομολόγησης σε δίκτυα δορυφορικών αστερισμών. Στην ενότητα αυτή καταγράφονται λόγοι χρήσης της IP σε δορυφορικά δίκτυα, τρόποι υλοποίησης, καθώς και προβλήματα που επιφέρει η χρήση IP δρομολόγησης στους δορυφόρους και πως αυτά αντιμετωπίζονται ή εξομαλύνονται από εναλλακτικές τεχνικές. Τέλος, στο κεφάλαιο 5 δίνονται τα συνολικά συμπεράσματα και τα κύρια αποτελέσματα της εργασίας αυτής.The subject, which is studied in this work, is the satellite communications systems and the routing techniques used in them. The purpose is to identify those features that affect the design of a satellite network and how these parameters are correlated. Another objective of this work is to examine whether the use of IP routing can be used on satellite networks as well as using IP on the terrestrial Internet. Moreover, it investigates the conditions under which this is achieved and which alternative techniques may help to this direction. A description of the topics covered in each of the chapters follows. In the first chapter there is a historical retrospection of satellites and services provided by satellite constellations. The subject of satellite systems is introduced through the presentation of concepts such as the formation of a constellation. It also records the options that exist for a satellite in terms of orbit type and altitude. Finally, Chapter 2 focuses on the basic features of a network formed by the satellite constellation. Mainly emphasis is placed on topology and connections between satellites, on delay, on mobility and its modeling, and on the process of handover. In Chapter 3, we study the design of a satellite constellation network and the parameters that need to be considered to create a functional and viable network. Initially, eight design goals for the satellite network are related to the quality of services we want to achieve, and then we analyze the network parameters that can affect these 8 goals. The parameters examined concern the structure of the constellation, the type of orbit, the altitude of the satellites as well as the number of both the orbits and the satellites. The results of this analysis led to the values of some network parameters that were used to simulate the particular design. The 4th chapter discusses the use of IP routing in satellite constellation networks. In this section, reasons for using IP on satellite networks, ways of implementation, as well as problems caused by the use of IP routing on satellites and alternative techniques to face them are discussed. Finally, chapter 5 gives the overall conclusions and the main results of this wor

Telecommunications Networks

This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing

A Secure and Efficient Communications Architecture for Global Information Grid Users via Cooperating Space Assets

With the Information Age in full and rapid development, users expect to have global, seamless, ubiquitous, secure, and efficient communications capable of providing access to real-time applications and collaboration. The United States Department of Defense’s (DoD) Network-Centric Enterprise Services initiative, along with the notion of pushing the “power to the edge,” aims to provide end-users with maximum situational awareness, a comprehensive view of the battlespace, all within a secure networking environment. Building from previous AFIT research efforts, this research developed a novel security framework architecture to address the lack of efficient and scalable secure multicasting in the low earth orbit satellite network environment. This security framework architecture combines several key aspects of different secure group communications architectures in a new way that increases efficiency and scalability, while maintaining the overall system security level. By implementing this security architecture in a deployed environment with heterogeneous communications users, reduced re-keying frequency will result. Less frequent re-keying means more resources are available for throughput as compared to security overhead. This translates to more transparency to the end user; it will seem as if they have a “larger pipe” for their network links. As a proof of concept, this research developed and analyzed multiple mobile communication environment scenarios to demonstrate the superior re-keying advantage offered by the novel “Hubenko Security Framework Architecture” over traditional and clustered multicast security architectures. For example, in the scenario containing a heterogeneous mix of user types (Stationary, Ground, Sea, and Air), the Hubenko Architecture achieved a minimum ten-fold reduction in total keys distributed as compared to other known architectures. Another experiment demonstrated the Hubenko Architecture operated at 6% capacity while the other architectures operated at 98% capacity. In the 80% overall mobility experiment with 40% Air users, the other architectures re-keying increased 900% over the Stationary case, whereas the Hubenko Architecture only increased 65%. This new architecture is extensible to numerous secure group communications environments beyond the low earth orbit satellite network environment, including unmanned aerial vehicle swarms, wireless sensor networks, and mobile ad hoc networks

Horizon 2020-funded security research projects with dual-use potential: An overview (2014-2018)

The analysis carried out in this report facilitates the identification of dual-use research topics and projects funded under Horizon 2020 that have a dual-use civilian/military potential, the results of which could be applied both by security and defence stakeholders (including industry). In this way, it could support the future security and defence research programmes in their attempt of avoiding duplication of investments and promoting synergies.JRC.E.7-Knowledge for Security and Migratio