  The advent of the Internet of Things (IoT) era, where billions of devices and
sensors are becoming more and more connected and ubiquitous, is putting a
strain on traditional terrestrial networks, that may no longer be able to
fulfill service requirements efficiently. This issue is further complicated in
rural and remote areas with scarce and low-quality cellular coverage. To fill
this gap, the research community is focusing on non-terrestrial networks
(NTNs), where Unmanned Aerial Vehicles (UAVs), High Altitude Platforms (HAPs)
and satellites can serve as aerial/space gateways to aggregate, process, and
relay the IoT traffic. In this paper we demonstrate this paradigm, and evaluate
how common Low-Power Wide Area Network (LPWAN) technologies, designed and
developed to operate for IoT systems, work in NTNs. We then formalize an
optimization problem to decide whether and how IoT traffic can be offloaded to
LEO satellites to reduce the burden on terrestrial gateways.
