Backhaul Aware Analysis of Cache-enabled Heterogeneous Networks

Abstract

Caching at base stations (BSs) has been proposed as a promising technology to address the challenges of the increasing traffic. In this article, cache-enabled heterogeneous networks (HetNets) considering the limited backhaul is analyzed with the aid of the stochastic geometry approach. A hybrid caching policy, in which the most popular contents are cached in the macro BSs tier with the deterministic caching strategy and the less popular contents are cached in the helpers tier with the probabilistic caching strategy, is proposed. Correspondingly, the content-centric association strategy is designed based on the comprehensive state of the access link, the cache and the backhaul link. By utilizing the hybrid caching policy, analytical expression of successful content delivery probability (SCDP) is derived. The simulation results show that the proposed caching policy outperforms the most popular caching policy in HetNets with the limited backhaul. SCDP increases with the increasing backhaul capacity until converging, whose convergence rate increases with the increment of cache capacity.