  With the dense deployment of millimeter wave (mmWave) front ends and
popularization of bandwidth-intensive applications, shared backhaul in
fiber-wireless (FiWi) networks is still facing a bandwidth crunch. To alleviate
the backhaul pressure, in this paper, caching capability is enabled at the edge
of FiWi networks, i.e., optical network unit access points (ONU-APs). On the
other hand, as both power budget and backhaul bandwidth in FiWi networks are
constrained, it is challenging to properly leverage power for caching and that
for wireless transmission to achieve superior system performance. As caching
has a significant impact on resource allocation, we reconsider performance
optimization and analysis in cache-enabled FiWi networks. Firstly, in the
cache-enabled FiWi network with mmWave, we formulate the joint power allocation
and caching problem, with the goal to maximize the downlink throughput. A
two-stage algorithm is then proposed to solve the problem. Secondly, to
investigate the theoretical capacity of the cache-enabled FiWi network with
mmWave, we derive an upper bound of the downlink throughput by analyzing
properties of the average rate of wireless links. Particularly, we show that
appropriate power allocation for wireless transmission and caching at ONU-APs
is essential to achieve higher throughput. The numerical and simulation results
validate our theoretical analysis and demonstrate the proposed algorithm can
approach the analytical upper bound.
