About the SnT The University of Luxembourg is an international research university with a distinctly multilingual and interdisciplinary character. The Interdisciplinary Centre for Security, Reliability and Trust ( SnT ) at the University of Luxembourg is a leading international research and innovation centre in secure, reliable and trustworthy ICT systems and services. We play an instrumental role in Europe by fueling innovation through research partnerships with industry, boosting R&D investments leading to economic growth, and attracting highly qualified talent.Welook forresearchers from diverse academic backgrounds to contribute to our projects in areas such as: Network Security, Information Assurance, Model driven Security, Cloud Computing, Cryptography, Satellite Systems, Vehicular Networks, and ICT Services & Applications. The SigCom research group of SnT, headed by Prof. Symeon Chatzinotas, focuses on wireless/satellite communications and networking. The research areas focus on the formulation, modeling, design, and analysis of future 6G communication networks that are capable of supporting new services for digital ecosystems. Use cases of interest include Security and Efficient Wireless Communication Solutions, IoT verticals, Unmanned Aerial Vehicles, Integrated Satellite Space Terrestrial Networks, Quantum Communications and Key Distribution, Spectrum Management and Coexistence, Tactile Internet, Earth Observation, and Autonomous Transportation. As far as technical enablers are concerned, we leverage expertise on advanced technologies including semantic/task oriented data processing, signal processing, network resource management to improve the performance of the future wireless communication systems. Finally, due to the large scale nature, complexity, and heterogeneity of 6G networks, for their analysis and optimization, we use tools such as artificial intelligence/machine learning, graph theory and graph signal processing, and convex/non convex optimization. Furthermore, our activities are experimentally driven and supported by the COMMLab, the 6GSPACE Lab, the HybridNetLab, the QCILab, our SW Simulators, and our Facilities. For further information, you may refer to https://www.uni.lu/snt en/research groups/sigcom/. Your role This PhD position is part of the "SHIELD Reliable Distributed Learning and Smart Contract assisted Digital Ecosystems" project funded by the FNR, according to the international research CHIST ERA Program, a consortium of research funding organizations in Europe and beyond supporting use inspired basic research in Information and Communication Technologies (ICT) or at the interface between ICT and other domains, see here: https://www.chistera.eu. The successful candidate will join the SIGCOM Research Group and work in SHIELD project which aims to employ optimization and distributed AI tools to address the technical challenges associated with NTNs supporting global digital ecosystems. Introduces a new