5G Satellite Transceiver Technologies for Non-Terrestrial Networks

This work is carried out in the context of transceiver technologies for 5G non-terrestrial networks (NTN), with a focus on the live in-orbit demonstration (LIDE) mission and related activities spanning hardware design, system analysis, and testbed implementation. LIDE is a European space agency (ESA)-founded project which aims to validate a 5G-compliant link between a user equipment (UE) and 5G node B (gNB) on ground, through a transparent satellite payload in K/Ka band. After introducing the fundamentals of satellite communications and the 5G new radio (5G NR) protocol stack, the study addresses NTN-specific design challenges, including Doppler shift, latency, constrained terminal capabilities, and higherlayer issues such as hybrid automatic repeat request (HARQ) under long propagation delays. The research is focused on the development and validation of K/Ka-band transceivers, presenting in-orbit demonstrations (IODs) with transparent payloads. A commercial-off-theshelf (COTS)-based upconverter architecture for low earth orbit (LEO) fixed-satellite service (FSS) applications was proposed, covering 17.3 GHz to 21.2 GHz with variable intermediate frequency (IF), and characterized in terms of spurious emissions, spurious-free dynamic range (SFDR), and error vector magnitude (EVM), achieving compliance with ITU recommendations. The payload design, integration with ground equipment, and qualification campaign are presented, along with 5G-specific testing in laboratory and in-orbit scenarios. The in-lab results confirm the feasibility of transparent payloads for NTN, with achieved data rates exceeding 1 Mbit s−1 uplink and 10 Mbit s−1 downlink at the user terminal. Two in-orbit demonstrations, by Picosats and the LIDE consortium, are presented. In the first IOD the transceiver capabilities are validated in orbit, showing also the transmission of a photo of the Earth taken from the relative satellite. LIDE IOD is presented as well; however, since the full ITU filing procedure was completed in September, only promising preliminary results are shown.