Joint Cache Placement and Content Scheduling in Integrated LEO Satellite-Terrestrial Networks
Qiongfang Liang, Yuan Liu, Weijun Tang · 2022 IEEE/CIC International Conference on Communications in China (ICCC) · 2022
With the advancement of computing and caching capacity of satellite onboard equipment, it is promising to leverage on-satellite cache technology in integrated satellite-terrestrial (IST) networks to improve transmission efficiency. However, traditional cache strategies are not suitable for IST networks due to dynamic satellite time-varying topology and propagation links. To address these problems, we propose a cooperative transmission scheme in IST networks to meet the users' quality of experience, where each user can sequentially get files from multiple moving satellites. Considering the capacity/time constraints of satellites and the completeness of requested files, we then formulate a mixed integer programming problem aiming at minimizing the average file transmission delay by jointly optimizing cache placement and content scheduling based on user requests. In order to solve this problem, we first propose an optimal algorithm and then design a low-complexity greedy algorithm. Simulation results show that the proposed cooperative caching and scheduling scheme achieves significant performance gains compared to other benchmarks. In addition, it shows that the proposed greedy algorithm achieves near-optimal performance.