University of Oulu

J. -H. Lee, H. Seo, J. Park, M. Bennis and Y. -C. Ko, "Learning Emergent Random Access Protocol for LEO Satellite Networks," in IEEE Transactions on Wireless Communications, vol. 22, no. 1, pp. 257-269, Jan. 2023, doi: 10.1109/TWC.2022.3192365

Learning emergent random access protocol for LEO satellite networks

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Author: Lee, Ju-Hyung1,2; Seo, Hyowoon3; Park, Jihong4;
Organizations: 1Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, USA
2School of Electrical and Computer Engineering, Korea University, Seoul, South Korea
3Department of Electronics and Communications Engineering, Kwangwoon University, Seoul, South Korea
4Author image of Jihong Park Jihong Park School of Information Technology, Deakin University, Geelong, VIC, Australia
5Centre for Wireless Communications, University of Oulu, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 2.9 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2022
Publish Date: 2023-03-02


A mega-constellation of low-altitude earth orbit (LEO) satellites (SATs) are envisaged to provide a global coverage SAT network in beyond fifth-generation (5G) cellular systems. LEO SAT networks exhibit extremely long link distances of many users under time-varying SAT network topology. This makes existing multiple access protocols, such as random access channel (RACH) based cellular protocol designed for fixed terrestrial network topology, ill-suited. To overcome this issue, in this paper, we propose a novel contention-based random access solution for LEO SAT networks, dubbed emergent random access channel protocol (eRACH). In stark contrast to existing model-based and standardized protocols, eRACH is a model-free approach that emerges through interaction with the non-stationary network environment, using multi-agent deep reinforcement learning (MADRL). Furthermore, by exploiting known SAT orbiting patterns, eRACH does not require central coordination or additional communication across users, while training convergence is stabilized through the regular orbiting patterns. Compared to RACH, we show from various simulations that our proposed eRACH yields 54.6% higher average network throughput with around two times lower average access delay while achieving 0.989 Jain’s fairness index.

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Series: IEEE transactions on wireless communications
ISSN: 1536-1276
ISSN-E: 1558-2248
ISSN-L: 1536-1276
Volume: 22
Issue: 1
Pages: 257 - 269
DOI: 10.1109/TWC.2022.3192365
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was supported by Institute of Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea government (MSIT) (No. 2021-0-00260, Research on LEO Inter-Satellite Links. Part of this work was be presented in part at the 2022 IEEE VTC Workshops.
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