Performance Analysis and Optimization of Caching Placement in Heterogeneous Wireless Networks

Caching at the network edge is regarded as a promising approach to handle content-dominated wireless traffic congestion problem and improve the quality of experience at mobile users (MUs). In this letter, we consider a heterogeneous wireless network (HetNet) where caches are not only deployed at base stations (BSs) but also at MUs. To study the caching optimization in such an HetNet, we first derive the analytical results of successful transmission probability (STP) using stochastic geometry. Then, we propose a subgradient descent algorithm (SGDA) to optimize the caching placement with an aim to maximize the STP. Simulations indicate that a significant performance gain can be obtained by our proposed solution when compared with existing caching placements.