IP-based routing algorithms for LEO satellite networks in near-polar orbits

In this work, several aspects on IP routing for LEO satellite networks are investigated. First, a proper downlink routing procedure is defined, which has the advantage to allow the identification of the egress satellite, without the need of information from GPS systems to determine the position of the destination mobile terminal. Furthermore, the performance of the routing algorithm that minimizes the number of hops are evaluated through simulations, for an Iridium-like and a Teldesic-like constellation in order to show the sensitivity of the routing algorithms to the availability of cross-seam ISLs. A modification of the "minimization of number of hops" algorithm is proposed, which allows to reduce the total path length, and hence, the end-to-end delay. The idea is to exploit as much as possible inter-plane ISLs at higher latitudes. The comparison between the two IP routing algorithms shows that the proposed algorithm can significantly reduce the end-to-end delay when the source interface and the destination interface are largely spaced in latitude and longitude.