Energy-efficient routing based on satellite–ground cooperation in optical satellite networks

The satellite–ground integrated optical network (SGION) is a key architecture for achieving global access and end-to-end low-latency communication, and it is also deemed a foundation of the 6G mobile network. The lifespan of satellites is primarily determined by the charge–discharge cycles of onboard batteries. Due to orbital motion, satellites in Earth’s shadow cannot harvest energy from solar panels and therefore must continuously discharge their batteries until they re-enter sunlight. Excessive battery discharge for communication tasks during shadow periods accelerates battery aging. To prevent network-wide lifespan degradation caused by over-discharge in shadow regions, this paper establishes a lifespan-consumption model and proposes an energy-efficient scheduling algorithm for satellite laser terminals, as well as an energy-efficient routing algorithm based on space–ground cooperation for SGIONs. We evaluate the proposed routing algorithm via extensive simulations on Walker constellations with 72, 288, and 1152 satellites. Compared with the shortest-path algorithm, the proposed method decreases the overall satellite lifespan consumption by 43.83%, reduces the maximum per-satellite consumption by 40.87%, increases the latency by 0.3 ms, and increases the blockage rate by 0.1%.