  Device-to-Device (D2D) communications can increase the throughput of cellular
networks significantly, where the interference among D2D links should be
properly managed. In this paper, we propose an opportunistic cooperative D2D
transmission strategy by exploiting the caching capability at the users to deal
with the interference among D2D links. To increase the cooperative opportunity
and improve spatial reuse gain, we divide the D2D users into clusters and cache
different popular files at the users within a cluster, and then find the
optimal cluster size. To maximize the network throughput, we assign different
frequency bands to cooperative and non-cooperative D2D links and optimize the
bandwidth partition. Simulation results demonstrate that the proposed strategy
can provide 500%-600% throughput gain over existing cache-enabled D2D
communications when the popularity distribution is skewed, and can provide
40%-80% gain even when the popularity distribution is uniform.
