Ubiquitous IoT Through Space Communications

Low-Power Wide-Area Networks (LPWANs) provide a low-cost solution for connecting low-power devices over long distances. Among LPWAN technologies, Narrowband IoT (NB-IoT) has gained prominence because of its wide coverage and high reliability. Recently, as the demand for IoT connectivity in remote and underserved regions continues to grow, integrating NB-IoT with Low-Earth Orbit (LEO) satellite networks has gained increasing attention. Due to satellite communication's dynamic nature, this integration poses significant challenges, including synchronization issues and managing high-density User Equipment (UE) during the random access procedure. This digest paper summarizes key contributions from a doctoral thesis that addresses these challenges. A systematic framework based on key performance indicators (KPIs) is proposed to evaluate and optimize satellite IoT communication, addressing reliability, latency, throughput, and energy efficiency trade-offs. A lightweight downlink synchronization method is proposed, which reduces device complexity in LEO satellite environments. In addition, a GNSS-free wake-up strategy is developed to improve energy efficiency, particularly in scenarios with intermittent satellite coverage. To address the challenge of random access in high-density environments, an early detection method is introduced. This method reduces collisions during the random access procedure and improves the network capacity to support many UEs. These contributions provide a comprehensive set of solutions to address the limitations of current NB-IoT and LEO satellite integration strategies, paving the way for efficient and scalable IoT networks in challenging environments.