Multiple Satellite Networks: Performance Evaluation via Simulation

A simulation that models networks having satellites and Earth stations as intercommunicating nodes is described. The orbital mechanics and Earth rotation cause the topology to be dynamic as nodes move in and out of range of each other or are eclipsed by the Earth. Each node has a directive steerable beam transmit antenna and an omnidirectional receive antenna. Link access is accomplished using a pure ALOHA protocol with link level acknowledgments. Either random routing or deterministic routing can be selected. Message traffic is parameterized by the mean distance between source and destination. The performance evaluation capabilities of the simulation tool are demonstrated by consideration of specific cases, including the analysis of two satellite constellations that are special in that all orbits are circular and at equal altitudes; this symmetry simplifies performance characterization. Output statistics presented include the end-to-end and link level throughput, message delays, and queue sizes.