Mobility-aware caching in energy-harvesting-powered small-cell networks

The rapid increase of mobile devices has made user mobility one of the important factors affecting the cache. With the development of energy harvesting technology, the cache must consider not only the quality of service but also the energy consumption, so the classic popular cache-based strategy is not the optimal strategy. For the above problems, this article proposes an optimization algorithm for user and small base station (SBS) caching strategies based on energy harvesting and mobility in cellular networks and device-to-device (D2D) scenarios. Considering the mobility of users and their social relationship, the cost function of users and SBS are respectively defined in combination with the cost of file transmission. The user's cost function includes its own cost and the cost of its "friends", while the SBS cost function is the cost of the entire system, and then the two caching problems are constructed as integer programming problems with cost minimization as the optimization goal. It is proved that the optimization objective function has the monotone submodular property and combined with the cache space and energy constraint, a greedy algorithm is proposed to optimize the caching strategy of users and SBS in turn. The simulation results show that the algorithm proposed in this paper can reduce the cost of transmission and make better use of cache and energy resources.