Faculty of Science, Technology and Medicine
Faculty of Law, Economics and Finance
Faculty of Humanities, Education and Social Sciences
Interdisciplinary Centre for Security, Reliability and Trust
Luxembourg Centre for Systems Biomedicine
Luxembourg Centre for Contemporary and Digital History
Luxembourg Centre for European Law
Luxembourg Centre for Socio-Environmental Systems
The Doctoral School in Science and Engineering is happy to invite you to Alejandro GONZÁLEZ GARRIDO’s defence entitled
Contributions to Hybrid 5G and GNSS for PNT applications
Supervisor: Dr Jorge QUEROL
Abstract:
The thesis provides a global navigation satellite systems (GNSS)-independent system leveraging 5G new radio (NR) as an integrated communications and positioning platform within non-terrestrial networks (NTN). A key contribution is a statistical interference model for the use of the positioning reference signal for navigation services in multi-satellite low Earth orbit (LEO) deployments. By using Monte Carlo analyses the aggregate interference is well described by a generalized extreme value (GEV) distribution, yielding practical interference bounds for link-budget design and system dimensioning.
Building on this characterization, two joint communication and positioning (JCAP) payload architectures for 5G-NTN are developed and optimized: (i) a so called “shared-beam” scheme that multiplexes a direct spread spectrum sequence (DSSS) for navigation with 5G signal for data within the same beam, and (ii) an “independent-beam” scheme that separates navigation and communications signals in different beams, where a wide navigation beam overlap all data beams, therefore a user will receive the signal from both services. Then, a Pareto analysis quantifies the tradeoff between spectral efficiency and positioning accuracy, demonstrating consistent meter-level accuracy with minimal spectral efficiency degradation.
Finally, a hybrid receiver for the JCAP waveform designed can offer the navigation observables and the data by using an extended Kalman filter for Doppler estimation, maintaining reliable tracking under strong interference from the data service and an uncoded bit error rate (BER) similar to dedicated data receivers.
Collectively, the results show that current NTN infrastructures, with modest modifications and full backward compatibility, can deliver resilient GNSS-independent PNT and lay groundwork for 6G convergence of communication and positioning.