Plenary Lecture
Prof. Dragorad Milovanovic and Prof. Zoran Bojkovic
University of Belgrade, Republic of Serbia
Title: Measurement-based modelling of integrated ground–sea–satellite
5G networks: A use case of Starlink broadband service in Greece
Abstract: Over the past decade, mobile networks have become the dominant mode of Internet access for billions of users worldwide. Despite significant expansion in terrestrial cellular coverage, large portions of the global population remain underserved, particularly in remote, rural, and sparsely populated areas. Since 2020, low Earth orbit (LEO) mega- constellations have emerged as a practical non-terrestrial network (NTN) solution for delivering fixed broadband Internet access. Modern satellite systems are designed to operate in close integration with them, supporting complementary and interoperable connectivity. This integration paradigm was formally standardized by the 3rd Generation Partnership Project (3GPP) in Release 17 through the introduction of 5G New Radio NR-NTN. Given the complexity and heterogeneity of real- world deployment environments, robust performance evaluation therefore necessitates a crowd-sourced, measurement- based modelling approach. Within this context, integrated ground–sea–satellite 5G NTN have emerged as a critical complementary layer to terrestrial infrastructure, particularly for island and isolated regions such as Greece. The country’s extensive archipelago and dense maritime corridors face structural connectivity challenges, where fiber backhaul is limited or prohibitively expensive, demand fluctuates sharply due to seasonal tourism, and network resilience is essential in the face of natural hazards such as storms, wildfires, and earthquakes. Key use cases therefore include island broadband access and seasonal capacity augmentation, maritime connectivity for ferries and shipping lanes, port and coastal logistics enablement through smart port services, and emergency communications for disaster response and recovery. The integrated NTN architectural ground segment comprises island and coastal 5G gNB base stations, a 5G Core (5GC) hosted on mainland Greece or in the cloud, multi-access edge computing (MEC) nodes deployed at ports or major islands, and SD-WAN-based aggregation of satellite and terrestrial links. The sea segment includes ferries, cruise ships, and offshore platforms equipped with maritime satellite terminals, onboard local area networks and Wi-Fi systems, and optionally private 5G small cells deployed on vessels. The space segment delivers high-capacity, low-latency IP connectivity, with inter-satellite links (ISLs) reducing reliance on proximal ground gateways—an essential capability for maintaining service continuity along open-sea routes. In late 2021, Greece established the regulatory framework that enabled Starlink to initiate limited operations, including testing activities and pre-order distribution of user equipment. Customer deliveries of Internet terminals began in May 2022, followed by the official nationwide launch of Starlink’s broadband service on March 28, 2023, when commercial subscriptions and user kits became fully available across the country. Today, Greece accounts for approximately 3.7% of Starlink’s top five global markets. The integration of ground–sea–satellite 5G connectivity with Starlink provides fiber-like broadband performance across Greek islands and maritime routes, while simultaneously laying the technological foundation for full 3GPP NR-NTN integration in the next generation 6G towards 2030. According to recent regional performance reports, Starlink’s broadband network in Greece achieved a median download speed of approximately 118.9 Mbps in Q3 2025. This value is derived from crowd-sourced Speedtest measurements and reflects the typical user experience. In practice, end-user throughput on individual terminals varies significantly, commonly ranging between 50 and 250 Mbps, depending on factors such as local network congestion, satellite visibility, terminal placement, and weather conditions. During the same period, Starlink’s median performance was reported to be roughly 60% higher than the national median fixed broadband speed in Greece, estimated at around 75 Mbps. Median latency is typically observed in the 40–70 ms range, making Starlink performance comparable to mid-tier terrestrial services in many scenarios. As a result, Starlink is well suited for interactive applications such as video conferencing, real-time collaboration, and cloud-based services, and is a viable option for integrated 5G NTN backhaul use cases where moderate latency is acceptable. The analysis of the Greek use case clearly shows that end-to-end Internet performance in such scenarios is not governed primarily by geographical distance, but rather by a combination of infrastructural, architectural, and logical factors. Beyond achieving low latency, NTN networks are increasingly expected to deliver stable and predictable performance characteristics across heterogeneous environments. Continued research and development are therefore essential to address remaining technical challenges and to fully unlock the benefits of an integrated 5G NTN approach.
Bio: To be announced soon