Content caching at base stations (BSs) and around of users is a hopeful and efficient approach to decrease the effects of traffic growth on wireless networks. In this study, we analyze performance metrics of content caching in a three-tier heterogeneous network (HetNet), including macro base stations (MBSs) for storing contents, small base stations (SBSs) and cacheusers (CUs) for storing the most popular contents, where all tiers are distributed according to independent Poisson point processes (PPPs). Specifically, we obtain closed-form expressions for the average outage probability and average delay experienced by the user in case of successful ARQ transmission. In particular, we show that due to the cache memory limitation, the popularity based on content distribution improves the efficiency of the proposed model. Eventually, the efficiency of considered model is illustrated by using numerical results.

Keywords