Joint Caching, Communication and Trajectory Optimization for UAVs in Space-Air-Ground Integrated Networks

To further improve the performance of wireless networks, the use of space-air-ground integrated architecture has been deemed promising. However, the study of the space-air-ground integrated network (SAGIN) is still incomplete. To contribute to this direction, this paper studies the joint caching, communication, and trajectory optimization for the SAGIN where UAV communications are aided with caching and the BS and satellite are used to provide backhaul links to UAVs. To conduct the optimization, we first propose a joint optimization problem aiming to maximize the minimum user-rate. Then, to solve the problem, we propose to decompose it into sub-problems and then solve the sub-problems iteratively. Solution approaches for each sub-problem are provided. In addition, simulations are conducted to evaluate our proposed optimization approach. Results show that our approach is effective and can outperform the reference schemes.