  Caching at mobile devices and leveraging device-to-device (D2D) communication
are two promising approaches to support massive content delivery over wireless
networks. The analysis of such D2D caching networks based on a physical
interference model is usually carried out by assuming that devices are
uniformly distributed. However, this approach does not fully consider and
characterize the fact that devices are usually grouped into clusters. Motivated
by this fact, this paper presents a comprehensive performance analysis and
joint communication and caching optimization for a clustered D2D network.
Devices are distributed according to a Thomas cluster process (TCP) and are
assumed to have a surplus memory which is exploited to proactively cache files
from a known library, following a random probabilistic caching scheme. Devices
can retrieve the requested files from their caches, from neighbouring devices
in their proximity (cluster), or from the base station as a last resort. Three
key performance metrics are optimized in this paper, namely, the offloading
gain, energy consumption, and latency.
