Technical Reports

Thesis Papers

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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 feasibility of using proposed commercial constellations to carry various classes of traffic between ground terminals and near-earth spacecraft.
• the performance optimization of such systems.

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.

[NASA NAG59150]

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.

[NASA NCC3528]

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 user’s requirements, and examine the system’s 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.

[NASA NAG59150]

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 user’s 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.

[NASA NCC3528]

Authenticated Key Agreement in Dynamic Groups (CSHCN TR 2002-1) by Arvind Mani

Multicast security poses interesting challenges in the area of key management. Designing a good protocol for key agreement in dynamic multicast groups involves a thorough understanding of the trade-offs that exist among storage, communication and computation overhead. The contribution of this thesis is a verifiable protocol for authenticated key agreement based on a distributed key generation scheme. The underlying key generation scheme has shown promise in being natural for collaborative group applications. The protocol can then be tailored to particular applications once we understand the communication, storage and computation constraints specific to the application. To handle group membership changes in dynamic groups, an auxiliary key agreement protocol is introduced. The auxiliary protocol re-uses contributions to the key in the previous round, to form the new key. The key shares of the members contributing fresh values in the current round are more susceptible to discovery by colluding group members (not outsiders). The auxiliary protocol does not introduce any other security weakness. A protocol that starts from the scratch on membership change is going to be expensive, slow and unsuitable for most applications. We use the well-known Logical Key Tree (LKH) structure to allow the key management (distribution) part of the protocol to scale to large groups. The key tree structure helps to localize the effect of membership change and as a result, reduces the communication overhead to form the new session key.

[NASA NCC3528 & ATIRP QK9931]

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