REVIEW article
Front. Space Technol.
Sec. Aerial and Space Networks
Volume 6 - 2025 | doi: 10.3389/frspt.2025.1580005
This article is part of the Research TopicLEO Multilayer Networking: Advancements and ChallengesView all articles
Handover Challenges in Disaggregated Open RAN for LEO Satellites: Tradeoff between Handover Delay, and Onboard Processing
Provisionally accepted
- 1Royal Institute of Technology, Stockholm, Sweden
- 2Ericsson (Sweden), Kista, Stockholm, Sweden
- 3Aalborg University, Aalborg, Denmark
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
With next-generation Low Earth Orbit (LEO) satellites, the shift from transparent architecture (acting as radio repeaters) to regenerative architecture (hosting part or all of the gNodeB (gNB) onboard) is expected. This regenerative architecture enables the disaggregation and distribution of Radio Access Network (RAN) functions between ground and space. Open RAN is a promising approach for Non-Terrestrial Networks (NTNs), offering flexible function placement through open interfaces. This study examines three Open RAN-based regenerative architectures: Split 7.2x (low-layer physical functions onboard), Split 2 (Layer 1 (L1) and Layer 2 (L2) onboard), and a gNB onboard the satellite. Handover (HO) management becomes increasingly complex in this disaggregated RAN, particularly for LEO satellites, where the part of gNB is constantly moving.The regenerative architecture choice and dynamic topology influence the additional HO control signaling required between the satellite and Ground Stations (GSs). Using a realistic dynamic LEO constellation model, we analyze the interplay between Conditional Handover (CHO) delay, computational complexity, and control signaling overhead under different network architectures.Our findings reveal that transitioning from a transparent architecture to Split 7.2x does not reduce CHO delay despite introducing additional onboard processing. gNB onboard the satellite minimizes cumulative CHO delay but demands 55%-70% more computational resources than Split 7.2x. Conversely, while Split 7.2x is computationally more efficient, it increases cumulative CHO delay by 25%-30%. Additionally, we observe that with limited onboard processing, only Transparent and Split 7.2x architectures support delay-sensitive services up to 100 ms. In contrast, with ample processing, gNB is suitable for stringent 50 ms requirements, while Split 2 best supports delay-tolerant services with 200 ms requirements.
Keywords: open radio access networks (Open RAN), non-terrestrial networks (NTN), functional splits, conditional handover, LEO satellites, regenerative architecture
Received: 19 Feb 2025; Accepted: 24 Apr 2025.
Copyright: © 2025 Seeram, Feltrin, Ozger, Zhang and Cavdar. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Siva Satya Sri Ganesh Seeram, Royal Institute of Technology, Stockholm, Sweden
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.