LAUSR

As a viable component of 6G wireless communication architecture, satellite-terrestrial networks support efficient file delivery by leveraging the innate broadcast ability of satellite and the enhanced powerful file transmission approaches of multi-tier terrestrial networks. In the paper, we introduce edge computing technology into the satellite-terrestrial network and propose a partition-based cache and delivery strategy to make full use of the integrated resources and reducing the backhaul load. Focusing on the interference effect from varied nodes in different geographical distances, we derive the file successful transmission probability of the typical user and by utilizing the tool of stochastic geometry. Considering the constraint of nodes cache space and file sets parameters, we propose a near-optimal partition-based cache and delivery strategy by optimizing the asymptotic successful transmission probability of the typical user. The complex nonlinear programming problem is settled by jointly utilizing standard particle-based swarm optimization (PSO) method and greedy based multiple knapsack choice problem (MKCP) optimization method. Numerical results show that compared with the terrestrial only cache strategy, Ground Popular Strategy, Satellite Popular Strategy, and Independent and identically distributed popularity strategy, the performance of the proposed scheme improve by 30.5%, 9.3%, 12.5% and 13.7%.