  The performance of cloud-based small cell networks (C-SCNs) relies highly on
a capacity-limited fronthaul, which degrade quality of service when it is
saturated. Coded caching is a promising approach to addressing these
challenges, as it provides abundant opportunities for fronthaul multicast and
cooperative transmissions. This paper investigates a cache-enabled C-SCNs, in
which small-cell base stations (SBSs) are connected to the central processor
via fronthaul, and can prefetch popular contents by applying maximum distance
separable (MDS) codes. To fully capture the benefits of fronthaul multicast and
cooperative transmissions, an MDS codes-aided transmission scheme is first
proposed. We formulate the problem to minimize the content delivery latency by
jointly optimizing fronthaul bandwidth allocation, SBS clustering, and
beamforming. To efficiently solve the resulting nonlinear integer programming
problem, we propose a penalty-based design by leveraging variational
reformulations of binary constraints. To improve the solution of the
penalty-based design, a greedy SBS clustering design is also developed.
Furthermore, closed-form characterization of the optimal solution is obtained,
through which the benefits of MDS codes can be quantified. Simulation results
are given to demonstrate the significant benefits of the proposed MDS
codes-aided transmission scheme.
