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, which significantly limit the performance of the orthogonal frequency division (OFDM) approach implemented in both LTE and 5G. Due to this, the research community is looking into other modulation schemes that can provide more robustness for high mobility wireless channels. A promising candidate in this respect is orthogonal time-frequency-space scheme (OTFS), which modulates the information bits in the delay and the Doppler domains.

Taking the lead from this, the thesis will focus on the study and investigation, also by means of simulations, of the OTFS modulation and its comparison to OFDM, with special attention to their performance for reception at LEO satellites. The student will have the chance to learn about IoT systems, satellite-based communications, and become familiar with concepts and waveforms that will become a core part of next generation wireless standards.