Demand Island Routing for LEO satellite constellations

Low Earth Orbit (LEO) constellations create a network that includes the satellites (as routing nodes) connected by Inter-Satellite Links (ISLs) and the terminals dynamically connected to one or more satellites. The combination of transient high rate changes in the network topology due to terminals handover, and the end-to-end high propagation time between the routing nodes presents a unique challenge for designing a guaranteed-bandwidth routing protocol that can support the frequent changes. In addition, terminals connected to multiple satellites can balance their traffic between multiple paths in a frame granularity based on the links conditions, and require real-time multipath guaranteed-bandwidth. Prior work focuses on end-to-end routing between multiple gateways and terminals and does not provide a multipath guaranteed-bandwidth service. 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 multipath service metrics (bandwidth and latency) and handling satellite handovers. A novel paradigm called Demand Islands is presented. This paradigm takes advantage of the geographical properties of the demand. The service area is split into geographical rectangles (Demand Islands), with a gateway (GW) located at the center of each island. Each Demand Island is dynamically associated with a set of satellites that cover it. We model the set of satellites as a grid. The routing algorithm uses the grid properties to provide real-time multipath guaranteed-bandwidth routing for the demand allocated to each terminal. Each satellite executes the algorithm to calculate the next hop for a received message in the time complexity of O(1). The analysis and simulation demonstrate the unique offering of the algorithm to route real-time guaranteed-bandwidth to terminals connected to multiple satellites.