SCP: Optimal Controller Placement in the LEO Satellite Network

Researchers are investigating new network architectures to achieve seamless global connectivity. One such proposal is the Space-Air-Ground Integrated Network (SAGIN), which integrates space, air, and ground networks. Efficient management of SAGIN layers can be achieved through effective network control, enabled by Software-Defined Network (SDN), where the placement of controller is crucial. This paper presents a heuristic-based SDN controller placement technique for Low Earth Orbit (LEO) satellites to determine the optimal number of controllers. The proposed method initially places controllers based on the average latency of the satellites, followed by iterative improvements using a Z-score-based approach. Different simulations are conducted on Iridium-like LEO satellite constellations demonstrate that the proposed technique significantly reduces the average latency and packet drop rate, even in scenarios where up to $\mathbf{7 5 \%}$ of the satellites are unavailable for controller placement.