Advanced Routing Algorithms for Low Orbit Satellite Constellations

As of 2018, several low orbit (LEO) constellations are being designed and planned. These include SpaceX, OneWeb, LeoSat, Telesat and lately Amazon Kuiper. Some of these constellations include Inter-Satellite Links (ISL) communication at the initial or second phase as well as on-board processing capabilities. The LEO constellations create a network that includes the satellites (as routing nodes) connected by ISLs, and the satellite terminals that dynamically connect to one or more satellites. The LEO network presents unique challenges to traffic routing and service planning due to dynamic changes in the network topology (interconnection between satellites, and between satellites and terminals). In addition, the LEO latency (which is low, compared to GEO and MEO) is significant when using legacy routing protocols (The constellation end-to-end latency can be in the order of 100 mSecs and ground-to-satellite latency is in the order of 10 mSecs).This paper addresses the problem of sending traffic from a source terminal to a destination terminal connected through multiple satellites while guaranteeing and enabling planning of the service metrics/QoS (bandwidth and latency) and handling satellite handovers.