LAUSR

Heterogeneous networks (HetNets) provide a powerful approach to cope with the dramatic mobile traffic growth. However, the backhaul limitation is an essential challenge. This paper is motivated to study how wireless caching and full duplex (FD) relaying can address the aforementioned challenge in a two-tier HetNet. Specifically, we propose a hybrid caching model consisting of probabilistic caching in the small base station (SBS) tier, and determinated but partially identical caching in the user equipment (UE) tier. Based on the proposed caching model, we disclose four types of content hitting-and-retrieving strategies embedded, where the last one relies on FD relaying to enhance transmissions. Based on a stochastic geometry modeling, we explicitly derive the content requester (CR) association probability, the content provider (CP) active probability, the CP average load, and the successful transmission probability (STP) for different strategies, respectively. All these beforehand derivations finally lead to the successful probability (SP) in closed form, which is the performance metric of the overall system. Explicitly, we demonstrate the improved offloading performance and the accuracy of derivations via simulations. Numerical results show that FD benefits the HetNet caching system effectively.