Publications Conference paper · Delay-tolerant networks · 2026

IR-CGR: Time-Aware Inter-Region Contact Graph Routing for Scalable Space DTNs

Shota Suzuki, Juan A. Fraire, and Keisuke Uehara

IEEE International Conference on Wireless for Space and Extreme Environments (WiSEE), Space-Terrestrial Internetworking Workshop (STINT), 2026

Abstract

Regionalization techniques scale Contact Graph Routing (CGR) in space Delay-Tolerant Networks by partitioning the network into routing regions, but existing local-knowledge schemes treat inter-region routing as a time-static problem: the set of viable passageways (nodes bridging two regions) is fixed at plan-derivation time. In orbital environments where passageway availability changes continuously, a statically selected passageway may have no contact left to carry a bundle onward by its arrival time, causing delivery failures. We propose IR-CGR, an Inter-Region Contact Graph Routing algorithm that constructs a time-aware Inter-Region Contact Plan (IRCP) over passageway nodes and applies contact-graph Dijkstra hierarchically at both intra- and inter-region levels, with a sampling parameter Δt that trades IRCP size against temporal resolution. Evaluations on a synthetic scaling model and the realistic Lunar Ring Road scenario show that IR-CGR sustains 100% delivery ratio, matching full-knowledge CGR, on sparse-relay lunar configurations where the static-vent baseline collapses to 53–72%. On the largest synthetic networks, IR-CGR reduces per-bundle computational cost to 7–29% of the full-knowledge baseline at its default sampling interval (Δt = 3600 s). Delivery delay remains within ∼1.9× of the full-knowledge reference on most sparse-relay configurations, with larger penalties confined to dense synthetic networks and degenerate lunar partitions.

Cite

BibTeX

@inproceedings{suzuki2026ircgr,
  author    = {Suzuki, Shota and Fraire, Juan A. and Uehara, Keisuke},
  title     = {{IR-CGR}: Time-Aware Inter-Region Contact Graph Routing for Scalable Space {DTNs}},
  booktitle = {IEEE International Conference on Wireless for Space and Extreme Environments (WiSEE), Space-Terrestrial Internetworking Workshop (STINT)},
  year      = {2026}
}

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