Content-Aware Proportional Caching for Efficient Data Delivery over Satellite Network

The Low Earth Orbit (LEO) satellite network has emerged as a crucial infrastructure for global content delivery service, due to its global coverage and low latency. However, the high mobility of satellites and the limited on-board resources impede its data distribution efficiency. In this paper, we propose CA-prop, a content-aware proportional caching scheme to improve the efficiency of content delivery over limited on-board cache resources. CA-prop captures the time-varying requesting feature of contents and leverage this metric to determine the caching proportion of a specific type of content. Based on the satellite weighted time-varying graph, a cooperative cache placement scheme is developed to cache the proportional content along the data delivery path. Furthermore, with prediction of satellite mobility and data delivery direction, we enhance CA-prop with a directional pre-caching strategy to increase the caching service residence time on the mobile large-scale satellite constellation. Our experiment results demonstrate that our strategy is effective in enhancing content distribution efficiency, with an average reduction of 43% in data delivery delay and 90% improvement in cache hit ratio under various content scenarios as compared to state-of-the-art approaches.