A Mobility-aware Proactive Caching Strategy in Heterogeneous Ultra-Dense Networks

Abstract

Caching on the wireless edge is a promising way to alleviate the backhaul burden of the heterogeneous ultra-dense network (H-UDN) and reduce the transmission delay. However, user mobility makes the content distribution more challenging for the association to small base stations (SBSs) always changes. In this paper, we propose a mobility-aware proactive caching strategy named MoPC in H-UDNs where each SBS can perceive the mobility pattern of users in neighbor SBSs. Moreover, by taking advantage of the hierarchical network feature, files requested by different speed users will be cached in different cache layers by amending content popularity. The cache placement problem is formulated with the aim of effective capacity maximization and solved by a genetic algorithm based approach. Simulation results prove that the proposed MoPC strategy outperforms other existing caching strategies in terms of both the transmission delay and cache hit ratio.