Explicit Load Balancing Technique for NGEO Satellite IP Networks With On-Board Processing Capabilities

科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究

On how to Mitigate the Packet Reordering Issue in the Explicit Load Balancing Scheme

科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究

ELB: An Explicit Load Balancing Routing Protocol for Multi-Hop NGEO Satellite Constellations

科研費報告書収録論文(課題番号:17500030/研究代表者:加藤寧/インターネットと高親和性を有する次世代低軌道衛星ネットワークに関する基盤研究

Secure Space Mesh Networking

Innoflight’s Secure Space Mesh Networking development and prototyping efforts started at its incorporation over 15 years ago with a vision of establishing end-to-end Internet Protocol (IP) connectivity in and through space. A number of space industry trends have accelerated the demand for space networking: (a) the widespread adoption of enterprise-grade and cloud-based, IP-centric ground system architectures; (b) the accelerated growth of both commercial and government proliferated Low Earth Orbit (pLEO) constellations leveraging small satellites (SmallSats); (c) the maturation, miniaturization and commoditization of high-speed Radio Frequency (RF), Free Space Optical (FSO) Inter-Satellite Links (ISLs), and high-performance flight processors for aforementioned SmallSats; and (d) the need for All-Domain Operations (ADO) seamlessly and autonomously integrating space, airborne, terrestrial, maritime and underwater networks. Furthermore, data encryption, for reasons of either National Security or monetized mission data protection, creates additional challenges to effectively switch/route and encrypt/decrypt ciphertext data across a mesh network. Lastly, with the projection of multiple and multi-national pLEO constellations, it is critical to negotiate link security real-time for dynamic, trusted nodes, and prevent inadvertent or intentional networking with unknown/untrusted nodes. Innoflight will discuss the aforementioned relevant space industry trends and commercial and government initiatives, including DARPA (Defense Advanced Research Projects Agency) Blackjack and Space Development Agency’s (SDA) National Defense Space Architecture (NDSA), and then identify the technical challenges for secure space mesh networking and decompose these challenges with two popular frameworks: (a) the individual layers, especially Layer 2 (data/link layer) and Layer 3 (network layer), within the Open Systems Interconnection (OSI) model; and (b) the control and data planes within the Software Defined Networking (SDN) model. Innoflight will present its development and prototyping efforts, specific to these challenges, including recent work funded under a 2019 Space Pitch Day award and leveraging its general-purpose processing and networking CFC-400X platform, and conclude by identifying remaining gaps: including technical, commercial and policy; to fully realize interoperable secure space mesh networking.

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

A Companion Study Guide for the Cisco DCICN Data Center Certification Exam (200-150)

The official Cisco DCICN book and practice exams are great resources, but this is not an easy exam. This study guide is a companion to those resources and summarizes the subject areas into additional review questions with an answer description for each item. This book is not a braindump and it is not bootleg screenshots of the actual exam. Instead, this book provides additional context and examples, serves to complement other study guides, and provides additional examples. If you are getting ready to take the exam for the first time, I hope that this guide provides the extra help to pass! If you are up for re-certification, I hope that this guide serves as a refresher and reminder! Keep working hard, keep studying, and never stop learning…https://digitalcommons.odu.edu/distancelearning_books/1000/thumbnail.jp

Data distribution satellite

A description is given of a data distribution satellite (DDS) system. The DDS would operate in conjunction with the tracking and data relay satellite system to give ground-based users real time, two-way access to instruments in space and space-gathered data. The scope of work includes the following: (1) user requirements are derived; (2) communication scenarios are synthesized; (3) system design constraints and projected technology availability are identified; (4) DDS communications payload configuration is derived, and the satellite is designed; (5) requirements for earth terminals and network control are given; (6) system costs are estimated, both life cycle costs and user fees; and (7) technology developments are recommended, and a technology development plan is given. The most important results obtained are as follows: (1) a satellite designed for launch in 2007 is feasible and has 10 Gb/s capacity, 5.5 kW power, and 2000 kg mass; (2) DDS features include on-board baseband switching, use of Ku- and Ka-bands, multiple optical intersatellite links; and (3) system user costs are competitive with projected terrestrial communication costs

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

Adaptation of the IEEE 802.11 protocol for inter-satellite links in LEO satellite networks

Knowledge of the coefficient of thermal expansion (CTE) of a ceramic material is important in many application areas. Whilst the CTE can be measured, it would be useful to be able to predict the expansion behaviour of multiphase materials.. There are several models for the CTE, however, most require a knowledge of the elastic properties of the constituent phases and do not take account ofthe microstructural features of the material. If the CTE could be predicted on the basis of microstructural information, this would then lead to the ability to engineer the microstructure of multiphase ceramic materials to produce acceptable thermal expansion behaviour. To investigate this possibility, magnesia-magnesium aluminate sp~el (MMAS) composites, consisting of a magnesia matrix and magnesium aluminate s~ne'l (MAS) particles, were studied. Having determined a procedure to produce MAS fr alumina and magnesia, via solid state sintering, magnesia-rich compositions wit ~ various magnesia contents were prepared to make the MMAS composites. Further, the l\.1MAS composites prepared from different powders (i.e. from an alumina-magnesia mixture ahd from a magnesia-spinel powder) were compared. Com starch was added into the powder mixtures before sintering to make porous microstructures. Microstructural development and thermal expansion behaviour ofthe MMAS composites were investigated. Microstructures of the MAS and the MMAS composites as well as their porous bodies were quaritified from backscattered electron micrographs in terms of the connectivity of solids i.e. solid contiguity by means of linear intercept counting. Solid contiguity decreased with increasing pore content and varied with pore size, pore shape and pore distribution whereas the phase contiguity depended strongly on the chemical composition and was less influenced by porosity. ' The thermal expansion behaviour of the MAS and the MMAS composites between 100 and 1000 °C was determined experimentally. Variation in the CTE ofthe MAS relates to the degree of spinel formation while the thermal expansion of the MMAS composites depends strongly on phase content. However, the MMAS composites with similar phase compositions but made from different manufacturing processes showed differences in microstructural features and thermal expansion behaviour. Predictions of the CTE values for composites based on a simple rule-of-mixtures (ROM) using volume fraction were compared with the measured data. A conventional ROM accurately predicted the effective CTE of a range of dense alumina-silicon carbide particulate composites but was not very accurate for porous multiphase structures. It provided an upper bound prediction as all experimental values were lower. Hence, the conventional ROM was modified to take account of quantitative microstructural parameters obtained from solid contiguity. The modified ROM predicted lower values and gave a good agreement with the experimental data. Thus, it has been shown that quantitative microstructural information can be used to predict the CTE of multiphase ceramic materials with complex microstructures.EThOS - Electronic Theses Online ServiceGBUnited Kingdo