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Technical Reports Authored or Co-Authored by Alex T. Nguyen (M.S.
Papers resulting from CSHCN-related research are periodically added to the Institute for Systems Research Technical Report Database where they can be browsed by year or searched by author or keywords.
Using Commercial Satellites to Provide Communication Support for Space Missions (CSHCN TR 2002-12) by Michael Hadjitheodosiou, Alex T. Nguyen
NASA is interested in using commercial satellites to provide broadband communications support for future space missions. In this paper, we describe a large-scale simulation model that we plan to use for detailed performance studies of critical parameters. We focus on the unique challenges we face and how we plan to use simulations to investigate:
The research and scientific content in this material has been published in the proceedings from the GLOBECOM2000 Symposium on Satellite Communications for the New Millennium, San Francisco, Nov, 2000.
Using Commercial Communication Satellite Constellations for Supporting Traffic from NASA Missions (CSHCN TR 2002-11) by Michael Hadjitheodosiou, Alex T. Nguyen
NASA is interested in using commercial satellites to provide broadband communications support for the International Space Station and other space missions. We describe a large-scale simulation model that we plan to use for detailed performance studies of critical parameters such as QoS guarantees for specific services, traffic routing schemes, transport protocol support, dynamic bandwidth allocation methods, queuing disciplines, and handoff strategies. In this paper we focus on the unique challenges we face and how we plan to use simulations to investigate: · the feasibility of using proposed commercial constellations to carry mission telemetry, command and control, and tele-science traffic between ground terminals and near-earth spacecraft. · the end-to-end performance optimization of such systems.
The research and scientific content in this material has been published in the proceedings from the 18th AIAA International Conference on Satellite Systems & Communications, Oakland, CA, April 2000.
Alternative Network Architectures for Supporting Communications from the International Space Station (CSHCN TR 2002-9) by Alex T. Nguyen, M. Hadjitheodosiou, J.S. Baras
In order to support the communications needs of the International Space Station (ISS), alternative communications architectures to provide broadband support need to be considered. We address three communications options and evaluate an architecture for the direct to ground option, which could serve as an intermediary solution to satisfy near term communications needs of commercial experiments and payloads on the ISS and overcome certain limitations of the current ISS communications infrastructure. We focus on a particular users requirements, and examine the systems communications links, and coverage availability. These parameters, along with high-level cost estimates, are compared to using commercial relay satellites, and an enhanced TDRSS. The direct to ground option is viable for store-and-forward applications and cost comparable to commercial constellations, but TDRSS is the choice for real-time or continuous data applications.
A Direct-to-Ground Architecture for Supporting Commercial Communications from the International Space Station (CSHCN TR 2002-6) by Alex T. Nguyen, X. Zhou, M. Hadjitheodosiou, J. Baras
We outline the first steps of an effort to start defining a communications architecture for supporting broadband data communications from the International Space Station. We address three communications options and focus on a direct-to-ground architecture, which could serve as an intermediary solution to satisfy near term communications needs of commercial experiments and payloads on the ISS and overcome certain limitations of the current ISS communications infrastructure. A high-level analysis of the architecture for the direct to ground option is performed, focusing on a particular users requirements, communications links, and coverage availability. We also discuss system, mobility support and protocol issues that need to be addressed for this solution to be a feasible alternative.
Extending IP Services to Future Space Missions (CSHCN TR 2001-10) by Michael Hadjitheodosiou, Alex T. Nguyen
We outline the first steps of an effort to start defining the communication architecture for the next generation of space missions that will support NASA's "faster, better, cheaper" concept and will enable new types of collaborative science, where investigators can access their data from space "anytime, anywhere" via direct communication with the instruments on the spacecraft.
We discuss the building blocks for a conceptual design of a network architecture that could support and take advantage of IP-capable spacecraft.
We show that access from a large number of ground stations (that could be directly connected to the existing Internet infrastructure) could increase spacecraft availability time by a significant factor.
We discuss possible multiple access techniques that could enable the transition to an on-demand operation, where spacecraft share space spectrum dynamically. We can also discuss the particular requirements of a next generation of missions consisting of constellations of several small spacecraft and introduce a number of new complex network control, scheduling, routing, data management and communication problems that need to be addressed for this topology.
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