  Broadcasting and multicasting services in LTE networks are shaping up to be
an effective way to provide popular content. A key requirement is that cells
are aggregated into areas where a tight time synchronization among
transmissions is enforced, so as to broadcast the same radio resources. Our
paper addresses a facet of LTE broadcasting that has so far received little
attention: the creation of broadcasting areas and the assignment of content to
them in order to efficiently exploit radio resources and satisfy user requests.
Our original clustering approach, named Single-Content Fusion, achieves these
goals by initially aggregating cells into single-content areas and maximizing
cell similarity in content interests. Aggregated areas are then merged into
multiple-content areas by virtue of similar spatial coverage. We show the
validity of our solution pointing out the advantages it provides in comparison
to other approaches. We also discuss the impact of various system factors
(e.g., number of served users, broadcast data rate, area size) and the
scalability of our proposal in large, realistic scenarios with both static and
time-varying user interest.
