  Caching of popular contents at cellular base stations, i.e., edge caching, in
order to eliminate duplicate transmission through the backhaul can reduce the
latency of data delivery in $5$G networks. However, since caching can only
reduce the backhaul delay, techniques such as base station densification will
also need to be used to reduce the fronthaul delay. In this paper, using
results from stochastic geometry, we first model the effects of base station
densification and cache size on the latency of the system. We then derive a
tight approximation for the cache hit probability. To optimize the network cost
due to the deployment of base station (BS) and cache storage, a minimization
problem for the product of the BS intensity and cache size is formulated under
probabilistic delay constraint, which is converted into a geometric program and
solved analytically. The results are then used to analyze the economics of a
cache-enabled virtualized cellular network where the network infrastructure,
i.e., BSs and cache storage, owned by an infrastructure provider (InP) is
shared among multiple mobile network operators (MNOs). For the pricing between
the InP and the MNOs, we formulate a Stackelberg game with the InP as the
leader and multiple MNOs as the followers. In this virtualized scenario, the
common cost of renting the infrastructure is shared in a fair manner among the
MNOs by using the Shapely value. An efficient algorithm is provided to divide
the rent among MNOs.
