Collaborative Edge Caching in LEO Satellites Networks: A MAPPO Based Approach

Low Earth Orbit satellite networks, as a crucial component of global low-latency internet access, are expected to carry significant user traffic in the future. Caching frequently requested content, e.g., popular videos on short-video platforms, in satellite networks can significantly alleviate traffic congestion. However, the satellite's brief overhead passing time, which is less than ten minutes, makes it difficult for satellites to capture the content popularity distribution. And the changing relative position between satellites poses challenges for cooperation. To address the challenges, we propose a method called SEC_MAPPO for deploying cooperative edge caching in satellite networks. First, we model this novel scenario and transform it into a Partially Observable Markov Decision Process (POMDP). Then, we design a multi-agent reinforcement learning algorithm specifically tailored for this scenario. Trace-driven simulation using a real-world LEO satellite constellation and video request dataset demonstrated that our proposed algorithm could achieve a reduction in average video request latency ranging from 4.53% to 9.31% compared to the baseline solutions.