Since the early days of satellite communications, the industry has pursued the idea of ubiquitous, global Internet connectivity. Today, driven by the cost reductions of the New Space era, the 3GPP is actively integrating satellites into traditional cellular networks under the concept of Non-Terrestrial Networks (NTN). This integration paves the way for future 6G standards, leveraging the massive footprint of satellites to extend coverage to unserved and under-served areas where terrestrial infrastructure falls short. To achieve this, the 3GPP is proposing to implement the 5G base station, i.e., Next Generation Node B (gNB), directly on board regenerative satellites. This thesis explores the two primary architectures resulting from this approach: the full gNB, where the satellite handles all functionality, and the split gNB, which distributes functionality between space and ground.
The first research line addresses the full gNB architecture, proposing a solution to the high barrier to entry that Mobile Network Operators (MNOs) face when accessing space infrastructure. The thesis introduces a multi-tenancy model where a Satellite Network Operator (SNO) manages the Radio Access Network (RAN) and grants access to multiple MNOs. This allows SNOs to maximize the utilization of costly space resources while enabling MNOs to offer NTN services without deploying their own complex satellite constellations. Furthermore, this collaboration aligns the goals of the space and mobile industries, promoting sustainability by preventing the proliferation of redundant mega-constellations in Low Earth Orbit (LEO).
The second research line demonstrates the feasibility and benefits of the split gNB architecture. This approach utilizes functional split technology to optimize the computational resources required on board the satellite, a critical factor for the SNOs’ strategies. The thesis investigates key industry questions, such as the system requirements necessary to support a split gNB in orbit and identifying the optimal split option for NTN deployments.
This thesis is expected to demonstrate the space multi-tenancy paradigm based on full gNB architectures in order to provide viable economic model where SNOs can monetize shared infrastructure, significantly lowering the capital expenditure barriers for MNOs to enter the space market. In parallel, the exploration of the split gNB architecture is expected to confirm that distributing network functions between space and ground is critical for overcoming the limited capabilities for on-board processing. Collectively, these findings contribute to the development of NTN in 5G, removing technical barriers to entry for industry and facing key aspects of the future of 6G.
