The Internet of things (IoT) is attracting an increasing attention from both industry and academia, and will be a core component of next generation 6G systems. In an IoT network, a potentially massive number of low-cost, low-complexity devices generate traffic to be reported to a common receiver monitoring the situation. Relevant examples include asset tracking, industrial and environmental monitoring as well as smart cities. In this context, the possibility to collect IoT messages via constellations of small satellites in low-Earth orbit is a key enabler to provide global connectivity, and has recently been introduced by 3GPP as part of the 5G standard. The reception of data at satellites that fly at high speed poses however also a number of technical challenges, such as signal distortions due to Doppler shift. The design of advanced waveforms at the physical and medium access control layer to enable efficient IoT communications via non-terrestrial networks will thus play a key role for the development of upcoming communications systems.

The thesis will focus on the investigation, also by means of network simulations, of the narrow-band IoT (NB-IoT) waveform currently supported by the 5G standard. Its performance over satellite links will be studied, in comparison with other recently proposed solutions for massive IoT access. The student will have the chance to learn about IoT systems, satellite-based communications, and become familiar with protocols that are a core part of 5G and next generation wireless standards.