  An integrated access and backhaul (IAB) network architecture can enable
flexible and fast deployment of next-generation cellular networks. However,
mutual interference between access and backhaul links, small inter-site
distance and spatial dynamics of user distribution pose major challenges in the
practical deployment of IAB networks. To tackle these problems, we leverage the
flying capabilities of unmanned aerial vehicles (UAVs) as hovering IAB-nodes
and propose an interference management algorithm to maximize the overall sum
rate of the IAB network. In particular, we jointly optimize the user and base
station associations, the downlink power allocations for access and backhaul
transmissions, and the spatial configurations of UAVs. We consider two spatial
configuration modes of UAVs: distributed UAVs and drone antenna array (DAA),
and show how they are intertwined with the spatial distribution of ground
users. Our numerical results show that the proposed algorithm achieves an
average of $2.9\times$ and $6.7\times$ gains in the received downlink
signal-to-interference-plus-noise ratio (SINR) and overall network sum rate,
respectively. Finally, the numerical results reveal that UAVs cannot only be
used for coverage improvement but also for capacity boosting in IAB cellular
networks.
