Towards ground station contact discovery in ring road networks

Delay-tolerant Networking protocols render a huge variety of novel communication scenarios possible. One of them is the so called Ring Road approach, a world-wide message-ferry network built upon Low-Earth Orbit (LEO) satellites used to transfer data between different ground stations. By this approach a world-wide communication network may be deployed at very low cost which allows for ad-hoc integration of ground stations into the overall network. Thus, it is possible to route data between isolated regions of the world and the Internet without explicit configuration effort. Essential for bringing this concept to realization is a neighbor discovery protocol enabling LEO satellites to discover new ground stations. The aim of this paper is to discuss the DTN IP Neighbor Discovery (IPND) protocol as a basis for a dedicated discovery approach. The resulting adapted version of IPND has been integrated into an existing DTN protocol implementation intended to be used on low-cost LEO satellites such as CubeSats. A technical realization has stood the test of practice and, thus, confirmed the applicability of the protocol for dynamic ground station discovery in a Ring Road network.