Medium Access Control Protocol for Satellite Constellations

Abstract

Satellite internet constellations have emerged as a promising solution for providing global internet connectivity, especially in regions underserved by terrestrial infrastructure. However, as user demand increases, especially in densely populated urban areas, existing Medium Access Control (MAC) protocols face significant scalability challenges and fail to take advantage of advanced antenna processing techniques, including phased array nulling, as well as capacity sharing via inter-satellite links. We present both an offline linear program and a novel online greedy MAC protocol to assign satellite resources to users using either sequential service, capacity sharing, or interference-aware nulling. Our offline formulation provides an upper bound on system performance, and while our online protocol is sub-optimal compared to this optimum, it is designed to be implementable on a real-time system. Simulations demonstrate that incorporating nulling can increase effective capacity by up to 25 times, substantially boosting profit in high-demand scenarios. We further quantify the performance gap between the online protocol and the offline optimum under varying demand distributions, showing that our online approach achieves near-optimal results in low-peakiness settings and gracefully degrades under more extreme conditions. These results highlight the importance of spatial processing at the MAC layer and offer practical design insights for future satellite internet constellations.