Performance Comparison of Optimal Routing and Dynamic Routing on Low-earth Orbit Satellite Networks

We compare the performances of two diierent routing schemes for LEO satellite networks through simulation. The rst one is a dynamic routing scheme based on the shortest-path algorithm. Its routing table is updated according to cost estimation based on link status information that is broadcasted periodically. The second one is an optimal routing scheme proposed by the authors of this paper, where a LEO satellite network is modeled by a Finite State Automaton (FSA). The states of the FSA are derived from the relative visibility on the basis of the constellation data. In each state, the LEO satellite network has a xed topology. Since LEO satellite networks exhibit periodic orbit movements, they can have only a nite number of states. In the proposed scheme, the link assignment and routing problems are solved oo-line for each state in the FSA using simulated annealing and the optimal routing algorithm. The resulting link assignment table and the routing table are stored at each satellite. As the system enters a new state, a new set of pre-computed tables are retrieved and used throughout the state. We also propose a scheme by which we can reduce probability of ongoing call blocking and analyze a proposed scheme through simulation.