An Integrated OTFS-NOMA Framework for Multi-Beam LEO Systems: Reliability and Capacity Analysis

ergodic capacity; Low earth orbit satellite; multi beam interference; NOMA; OTFS; outage probability; performance analysis; Ergodic capacity; Low earth orbit satellites; Multibeam interferences; Multiple access; Non-orthogonal; Non-orthogonal multiple access; Orthogonal time frequency space; Outage probability; Performances analysis; Time-frequency space; Computer Science Applications; Electrical and Electronic Engineering; Applied Mathematics

Abstract :

[en] Multi-beam low earth orbit (LEO) satellite communications, as an essential component for 6G systems, may encounter challenges from severe Doppler shifts and co-channel interference. This paper addresses a realistic problem in 6G-LEO systems, that is, how to meet the high-reliability demands of massive high-mobility terminals. We propose an integrated framework to exploit the synergy of non-orthogonal multiple access (NOMA) and orthogonal time frequency space (OTFS). OTFS modulation is employed to achieve full time-frequency diversity to combat Doppler shifts, while NOMA is used to accommodate more access requests. Specifically, within each beam, power domain superposition is applied to the delay-Doppler domain, enabling multiple terminals to share delay-Doppler grid resources. We analyze the performance of reliability, outage probability and ergodic capacity. Notably, we derive a novel closed-form expression to characterize the distribution of multi-beam interference with varying beam gains. Theoretical analysis and simulation results confirm that the proposed framework achieves a substantially lower outage probability compared to conventional OFDM schemes, with a system capacity improvement exceeding 11.9%.

Disciplines :

Computer science

Author, co-author :

Zhao, Xiaohui ; Xi’an Jiaotong University, School of Information and Communications Engineering, Xi’an, China

LEI, Lei ; University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust > SigCom > Team Symeon CHATZINOTAS ; Xi’an Jiaotong University, School of Information and Communications Engineering, Xi’an, China

Wei, Zhiqiang ; Xi’an Jiaotong University, School of Mathematics and Statistics, Xi’an, China ; Peng Cheng Laboratory, Shenzhen, China ; Pazhou Laboratory (Huangpu), Guangzhou, China

Fang, Hai ; Xi’an Institute of Space Radio Technology, Xi’an, China

Wang, Wenjie; Xi’an Jiaotong University, School of Information and Communications Engineering, Xi’an, China

CHATZINOTAS, Symeon ; University of Luxembourg > Interdisciplinary Centre for Security, Reliability and Trust (SNT) > SigCom ; Kyung Hee University, College of Electronics and Information, Yongin-si, South Korea

External co-authors :

yes

Language :

English

Title :

An Integrated OTFS-NOMA Framework for Multi-Beam LEO Systems: Reliability and Capacity Analysis

Publication date :

18 August 2025

Journal title :

IEEE Transactions on Wireless Communications

ISSN :

1536-1276

eISSN :

1558-2248

Publisher :

Institute of Electrical and Electronics Engineers Inc.

Pages :

1-1

Peer reviewed :

Peer Reviewed verified by ORBi

Additional URL :

http://xplorestaging.ieee.org/ielx8/7693/4656680/11126946.pdf?arnumber=11126946

Funders :

National Natural Science Foundation of China

Funding text :

This work was supported in part by the National Natural Science Foundation of China (NSFC) project under Grant 62471375; in part by the Natural Science Foundation of Sichuan Province, China, under Grant 2023NSFSC0455; in part by the National Key Laboratory Foundation under Grant 2023-JCJQ-LB-007, in part by the Qin Chuangyuan Innovation and Talent Project under Grant QCYRCXM-2023-049, and in part by the Key Research and Development Program of Shaanxi under Grant 2024GX-YBXM-065. The work of S.Chatzinotas was partially funded by the ETHER project of Smart Networks and Services Joint Undertaking (SNS JU) under the European Unions Horizon Europe research and innovation programme under Grant Agreement No. 101096526. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union. Neither the European Union nor the granting authority can be held responsible for them. Part of this work will be presented at the 2024 IEEE/CIC International Conference on Communications in China, Hangzhou, China, 2024.

Available on ORBilu :

since 27 November 2025

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Bibliography

L. Lei, A. Wang, E. Lagunas, X. Hu, Z. Zhang, Z. Wei, and S. Chatzinotas, “Spatial-temporal resource optimization for uneven-traffic LEO satellite systems: Beam pattern selection and user scheduling,” IEEE Journal on Selected Areas in Communications, vol. 42, no. 5, pp. 1279–1291, 2024.
M. Giordani and M. Zorzi, “Non-terrestrial networks in the 6G era: Challenges and opportunities,” IEEE Network, vol. 35, no. 2, pp. 244–251, 2021.
T. Hwang, C. Yang, G. Wu, S. Li, and G. Ye Li, “OFDM and its wireless applications: A survey,” IEEE Transactions on Vehicular Technology, vol. 58, no. 4, pp. 1673–1694, 2009.
J. Shi, Z. Li, J. Hu, Z. Tie, S. Li, W. Liang, and Z. Ding, “OTFS enabled LEO satellite communications: A promising solution to severe doppler effects,” IEEE Network, vol. 38, no. 1, pp. 203–209, 2024.
R. Hadani, S. Rakib, M. Tsatsanis, A. Monk, A. J. Goldsmith, A. F. Molisch, and R. Calderbank, “Orthogonal time frequency space modulation,” in 2017 IEEE Wireless Communications and Networking Conference (WCNC), 2017, pp. 1–6.
Z. Zhou, L. Liu, J. Xu, and R. Calderbank, “Learning to equalize OTFS,” IEEE Transactions on Wireless Communications, vol. 21, no. 9, pp. 7723–7736, 2022.
S. K. Mohammed, “Derivation of OTFS modulation from first principles,” IEEE Transactions on Vehicular Technology, vol. 70, no. 8, pp. 7619–7636, 2021.
H. B. Mishra, P. Singh, A. K. Prasad, and R. Budhiraja, “OTFS channel estimation and data detection designs with superimposed pilots,” IEEE Transactions on Wireless Communications, vol. 21, no. 4, pp. 2258–2274, 2022.
Y. Liu, S. Zhang, F. Gao, J. Ma, and X. Wang, “Uplink-aided high mobility downlink channel estimation over massive MIMO-OTFS system,” IEEE Journal on Selected Areas in Communications, vol. 38, no. 9, pp. 1994–2009, 2020.
Z. Wei, S. Li, W. Yuan, R. Schober, and G. Caire, “Orthogonal time frequency space modulationpart i: Fundamentals and challenges ahead,” IEEE Communications Letters, vol. 27, no. 1, pp. 4–8, 2023.
S. Li, W. Yuan, Z. Wei, R. Schober, and G. Caire, “Orthogonal time frequency space modulationpart ii: Transceiver designs,” IEEE Communications Letters, vol. 27, no. 1, pp. 9–13, 2023.
W. Yuan, Z. Wei, S. Li, R. Schober, and G. Caire, “Orthogonal time frequency space modulationpart iii: Isac and potential applications,” IEEE Communications Letters, vol. 27, no. 1, pp. 14–18, 2023.
X. Wang, W. Shen, C. Xing, J. An, and L. Hanzo, “Joint bayesian channel estimation and data detection for OTFS systems in LEO satellite communications,” IEEE Transactions on Communications, vol. 70, no. 7, pp. 4386–4399, 2022.
S. Li, M. Zhang, C. Ju, D. Wang, W. Chen, P. Zhou, and D. Wang, “Downlink carrier frequency offset estimation for OTFS-based LEO satellite communication system,” IEEE Communications Letters, vol. 28, no. 1, pp. 163–167, 2024.
S. K. Devarajalu and D. Jose, “Performance evaluation of OTFS under different channel conditions for LEO satellite downlink,” in 2023 10th International Conference on Wireless Networks and Mobile Communications (WINCOM), 2023, pp. 1–6.
J. Hu, J. Shi, S. Ma, and Z. Li, “Secrecy analysis for orthogonal time frequency space scheme based uplink LEO satellite communication,” IEEE Wireless Communications Letters, vol. 10, no. 8, pp. 1623–1627, 2021.
J. Shi, J. Hu, Y. Yue, X. Xue, W. Liang, and Z. Li, “Outage probability for OTFS based downlink LEO satellite communication,” IEEE Transactions on Vehicular Technology, vol. 71, no. 3, pp. 3355–3360, 2022.
C. Xu, L. Xiang, J. An, C. Dong, S. Sugiura, R. G. Maunder, L.-L. Yang, and L. Hanzo, “OTFS-aided ris-assisted SAGIN systems outperform their OFDM counterparts in doubly selective high-doppler scenarios,” IEEE Internet of Things Journal, vol. 10, no. 1, pp. 682–703, 2023.
Z. Ding, R. Schober, P. Fan, and H. Vincent Poor, “OTFS-NOMA: An efficient approach for exploiting heterogenous user mobility profiles,” IEEE Transactions on Communications, vol. 67, no. 11, pp. 7950–7965, 2019.
X. Zhou, K. Ying, Z. Gao, Y. Wu, Z. Xiao, S. Chatzinotas, J. Yuan, and B. Ottersten, “Active terminal identification, channel estimation, and signal detection for grant-free NOMA-OTFS in LEO satellite internet-of-things,” IEEE Transactions on Wireless Communications, vol. 22, no. 4, pp. 2847–2866, 2023.
Y. Ma, G. Ma, N. Wang, Z. Zhong, J. Yuan, and B. Ai, “Enabling OTFSTSMA for smart railways mMTC over LEO satellite: A differential doppler shift perspective,” IEEE Internet of Things Journal, vol. 10, no. 6, pp. 4799–4814, 2023.
X. Zhao, L. Lei, Z. Wei, H. Fang, and W. Wang, “Closed-form outage probability analysis for OTFS-based multi-beam LEO satellites,” in 2024 IEEE/CIC International Conference on Communications in China (ICCC), 2024, pp. 769–773.
A. Abdi, W. Lau, M.-S. Alouini, and M. Kaveh, “A new simple model for land mobile satellite channels: first- and second-order statistics,” IEEE Transactions on Wireless Communications, vol. 2, no. 3, pp. 519–528, 2003.
P. Raviteja, K. T. Phan, Y. Hong, and E. Viterbo, “Interference cancellation and iterative detection for orthogonal time frequency space modulation,” IEEE Transactions on Wireless Communications, vol. 17, no. 10, pp. 6501–6515, 2018.
M. Abdelfatah, A. Zekry, and S. ElSayed, “User selection methods for overcoming growing number of served users in massive mimo systems,” IEEE Access, vol. 11, pp. 59 981–59 994, 2023.
Z. Yang, Z. Ding, P. Fan, and N. Al-Dhahir, “A general power allocation scheme to guarantee quality of service in downlink and uplink noma systems,” IEEE Transactions on Wireless Communications, vol. 15, no. 11, pp. 7244–7257, 2016.
G. Zheng, S. Chatzinotas, and B. Ottersten, “Generic optimization of linear precoding in multibeam satellite systems,” IEEE Transactions on Wireless Communications, vol. 11, no. 6, pp. 2308–2320, 2012.
L. You, X. Qiang, K.-X. Li, C. G. Tsinos, W. Wang, X. Gao, and B. Ottersten, “Massive mimo hybrid precoding for leo satellite communications with twin-resolution phase shifters and nonlinear power amplifiers,” IEEE Transactions on Communications, vol. 70, no. 8, pp. 5543–5557, 2022.
N. I. Miridakis, D. D. Vergados, and A. Michalas, “Dual-hop communication over a satellite relay and shadowed rician channels,” IEEE Transactions on Vehicular Technology, vol. 64, no. 9, pp. 4031–4040, 2015.
T. S. Kelso, “Analysis of the Iridium 33-Cosmos 2251 collision,” Adv. Astronautical Sci., vol. 135, pp. 1009–1112, 2009.
G. D. Surabhi and A. Chockalingam, “Low-complexity linear equalization for otfs modulation,” IEEE Communications Letters, vol. 24, no. 2, pp. 330–334, 2020.
I. S. Gradshteyn and I. M. Ryzhik, Table of integrals, series, and products, 7th ed. San Diego, CA, USA: Academic, 2007.