The University of Luxembourg, a modern and international research university, is offering a PhD position in Multi-Connectivity for Multi-Orbit Satellite Systems within its Interdisciplinary Centre for Security, Reliability and Trust (SnT). The successful candidate will join the SIGCOM research group, led by Prof. Symeon Chatzinotas, which specializes in telecommunication and networking systems, including non-terrestrial networks (NTNs) and quantum communication infrastructure. The research will focus on developing advanced reliability and connectivity techniques for multi-orbit satellite systems, such as GEO-MEO-LEO architectures, in close collaboration with the industrial partner SES. Key responsibilities include designing and evaluating multi-connectivity frameworks, optimizing and experimentally validating MC-based reliability solutions, and disseminating findings through scientific journals and conferences. Applicants should possess an M.Sc or M.Eng degree in Electrical and Electronics Engineering, Telecommunications Engineering, or Computer Science/Engineering, with strong backgrounds in digital signal processing and mathematics. Experience or interest in wireless, mobile, satellite communications, NTNs, 5G/6G technologies, communication system modelling, performance analysis, simulation, optimization, and machine learning is expected. Hands-on experience with software-defined radios (SDRs) and/or OpenAirInterface5G software stack, as well as programming skills in MATLAB, Python, or C/C++, are desirable. Fluency in English is required, and knowledge of French, German, or Luxembourgish is advantageous. The position offers a fixed-term contract of 36 months (extendable up to 48 months), a yearly gross salary of EUR 41,976, and access to high-quality equipment and a dynamic, multicultural environment. The University of Luxembourg is committed to gender parity, inclusion, and diversity. Applications should include a full CV, transcripts, cover letter, and should be submitted online via the university's HR system. Early applications are encouraged as they will be processed upon reception.