  The densification of small-cell base stations in a 5G architecture is a
promising approach to enhance the coverage area and facilitate the ever
increasing capacity demand of end users. However, the bottleneck is an
intelligent management of a backhaul/fronthaul network for these small-cell
base stations. This involves efficient association and placement of the
backhaul hubs that connects these small-cells with the core network.
Terrestrial hubs suffer from an inefficient non line of sight link limitations
and unavailability of a proper infrastructure in an urban area. Seeing the
popularity of flying platforms, we employ here an idea of using networked
flying platform (NFP) such as unmanned aerial vehicles (UAVs), drones, unmanned
balloons flying at different altitudes, as aerial backhaul hubs. The
association problem of these NFP-hubs and small-cell base stations is
formulated considering backhaul link and NFP related limitations such as
maximum number of supported links and bandwidth. Then, this paper presents an
efficient and distributed solution of the designed problem, which performs a
greedy search in order to maximize the sum rate of the overall network. A
favorable performance is observed via a numerical comparison of our proposed
method with optimal exhaustive search algorithm in terms of sum rate and
run-time speed.
