In recent years, IoT applications have drawn a great deal of attention, both in academia and industry. A crucial requirement of any infrastructure serving the IoT market will be to guarantee ubiquitous connectivity to the low-cost, low-powered devices distributed all over the globe. It is widely accepted that this requirement will not be met by the terrestrial network alone. There will be, in fact, vast areas of the globe where the terrestrial infrastructure deployment will be unfeasible or not economically viable, thus leaving those areas un- or under-served. For this reason, several studies and projects are addressing the use of a Non-Terrestrial Network component to seamlessly complement and extend the terrestrial network coverage in fut...