Space Cloudlet Aided Caching Placement Strategy for Remote Mobile Social Networks

In remote mobile social networks, caching is a very promising technique to alleviate the burden of space cloudlet (e.g., cache-enabled satellite user terminal) and to improve subscribers' user experience in terms of content retrieval latency. In this paper, we proposed a social relationship aware caching placement approach for remote mobile social networks. Social relationships between users are used to designate a set of helpers with caching capability, which can cache popular files proactively when the cloudlet is idle. Furthermore, the caching placement problem is formulated as an optimization problem to minimize the average content retrieval latency. Then, we reformulate the problem into a monotone submodular optimization problem with a partition matroid constraint; moreover, an efficient greedy algorithm with $1-\frac{1}{e}$ approximation ratio is proposed to solve it. Simulation results show that the proposed social aware greedy caching placement approach significantly outperforms the traditional approaches in terms of content retrieval latency and hit ratio.