On the Architectural Split and Radio Intelligence Controller Placement in Integrated O-RAN-enabled Non-Terrestrial Networks

2025-07-03

AI Summary

Integrating terrestrial and non-terrestrial networks (TNN) in space–ground integrated networks faces challenges including ambiguous functional split definitions, constrained near-real-time RAN Intelligent Controller (RIC) deployment due to limited on-board computing resources, and highly dynamic satellite topologies. Method: This paper proposes an O-RAN-aligned co-design architecture: (i) a unified functional split taxonomy clarifying optimal distribution of RAN and core network functions across space and ground nodes; (ii) an elastic deployment strategy for Near-RT and Non-RT RICs, enabling on-board UPF/gNB integration and intra-/inter-satellite collaborative processing; and (iii) a mapping model linking functional splits with RIC deployment, quantifying latency, scalability, and interoperability constraints. Contribution/Results: The framework provides a standardized, modular pathway toward O-RAN-compliant space–ground convergence, significantly enhancing system adaptability and resource efficiency while supporting heterogeneous, dynamic network environments.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Intelligent Robots: Multi-Robot Systems
• Search and Optimization: Distributed Search

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs
• Search and Retrieval-Augmented AI: Vertical and domain-specific search

Abstract

The integration of Terrestrial Networks (TNs) with Non-Terrestrial Networks (NTNs) poses unique architectural and functional challenges due to heterogeneous propagation conditions, dynamic topologies and limited on-board processing capabilities. This paper examines architectural and functional split strategies that are consistent with O-RAN principles for future integrated TN-NTN systems. A taxonomy of split options is proposed that distributes RAN and core functions between satellites and ground nodes, and trade-offs in terms of performance, latency, autonomy and deployment are analysed. In particular, we evaluate configurations ranging from pure on-board DU deployments to full gNB and UPF integration into satellites, including variations based on intra- and inter-satellite processing. In addition, the placement of Near-RT and Non-RT RAN Intelligent Controllers (RICs) is discussed, proposing flexible split strategies between space and ground to optimise the performance and scalability of the control loop. A comprehensive mapping between architectural splits and RIC placement options is provided, emphasising implementation constraints and interoperability considerations. The paper concludes by identifying key challenges and outlining future directions to enable standardised, modular and efficient TN-NTN convergence in the context of the O-RAN.

Problem

• Examining O-RAN-compatible split strategies for TN-NTN integration
• Analyzing trade-offs in RAN/core function distribution between satellites and ground
• Optimizing RIC placement for control loop performance and scalability

Innovation

• Proposes O-RAN-compatible TN-NTN split strategies
• Evaluates satellite-ground function distribution trade-offs
• Optimizes RIC placement for control loop performance