  A cloud radio access network (C-RAN) is considered as a candidate to meet the
expectations of higher data rate de- mands in wireless networks. In C-RAN, low
energy base stations (BSs) are deployed over a small geography and are allowed
to connect to the cloud via finite capacity backhaul links where the
information is processed. A conventional C-RAN, however, requires high capacity
backhaul links, since the requested files need to be transferred first from the
cloud to the BS before conveying them to the users. One approach to overcome
the limitations of the backhaul links is to introduce local storage caches at
the BSs, in which the popular files are stored locally in order to reduce the
load of the backhaul links. Furthermore, we utilize coded caching with the goal
to minimize the total network cost, i.e., the transmit power and the cost
associated with the backhaul links. The initial formulation of the optimization
problem for this model is non-convex. We first reformulate and then convexify
the problem through some relaxation techniques. In comparison to the uncoded
caching at the BSs, our results highlight the benefits associated with coded
caching and show that it decreases the backhaul cost.
