  We consider a hybrid delivery scheme for streaming content, combining
cache-enabled Orthogonal Multipoint Multicast (OMPMC) and on-demand
Single-Point Unicast (SPUC) transmissions for heterogeneous networks. The OMPMC
service transmits cached files through the whole network to interested users,
and users not being satisfied by this service are assigned to the SPUC service
to be individually served. The SPUC fetches the requested files from the core
network and unicasts them to UEs using cellular beamforming transmissions. We
optimize the delivery scheme to minimize the average resource consumption in
the network. We formulate a constrained optimization problem over the cache
placement and resource allocation of the OMPMC component, as well as the
multi-user beamforming scheme of the SPUC component. We apply a path-following
method to find the optimal traffic offloading solution. The solutions portray a
contrast between the total amount of consumed resources and service outage
probability. Simulation results show that the hybrid scheme provides a better
tradeoff between the amount of network-wide consumed resources and the service
outage probability, as compared to schemes from the literature.
