Analysis and Optimization of Random Caching in mmWave Heterogeneous Networks

Abstract

In this paper, we investigate the optimal caching policy in a K-tier millimeter wave (mmWave) cache-enabled heterogeneous network. In order to mitigate interferences, we incorporate base station (BS) idling into our analysis. Under the random caching framework, we derive the association probability for each tier as well as the successful transmission probability (STP) by utilizing stochastic geometry and taking the blockage effect into account. In addition, we adopt the Convex-Concave Procedure (CCP) to obtain the locally optimal caching probabilities and propose a two-stage scheme to obtain the globally optimal caching probabilities under the special case where the blockage parameters for K tiers are sufficiently small. Numerical results demonstrate the superiority of the proposed method over the conventional caching strategies such as Most Popular Content (MPC) and Uniform Caching (UC) and the truncated Zipf distribution-based caching schemes.