Effects of Power Amplifier Nonlinearity on OTFS Signals

Hariniony Bienvenu Rakotonirina; Marie Emile Randrianandrasana

doi:doi:10.11648/j.wcmc.20251202.15

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Effects of Power Amplifier Nonlinearity on OTFS Signals

Hariniony Bienvenu Rakotonirina^*

, Marie Emile Randrianandrasana

Published in International Journal of Wireless Communications and Mobile Computing (Volume 12, Issue 2)

Received: 17 November 2025 Accepted: 8 December 2025 Published: 30 December 2025

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Abstract

Orthogonal Time Frequency Space (OTFS) modulation has emerged as a leading candidate for 6G wireless systems due to its exceptional robustness against high mobility and frequency-selective fading channels. However, its multicarrier structure inherently generates a high Peak-to-Average Power Ratio (PAPR), making OTFS signals highly susceptible to nonlinear distortions introduced by High Power Amplifiers (HPAs). This paper investigates the impact of HPA nonlinearity on OTFS transmission in terrestrial radio environments, using the Rapp model to characterize amplifier behavior. We evaluate key performance metrics including PAPR, Complementary Cumulative Distribution Function (CCDF), Bit Error Rate (BER), Adjacent Channel Power Ratio (ACPR), and amplifier efficiency under varying Input Back-Off (IBO) values (0.5 dB to 4 dB). Our results demonstrate that OTFS exhibits a significantly higher PAPR than conventional 16-QAM, necessitating a larger IBO to avoid saturation. While increasing IBO improves linearity and reduces BER particularly in realistic Rayleigh fading channels it comes at the cost of drastically reduced amplifier efficiency, dropping from 70% at IBO = 0 dB to below 15% at IBO = 6 dB. Furthermore, nonlinear amplification severely degrades spectral purity: ACPR deteriorates from -37 dB (before amplification) to -15 dB (after amplification), indicating a 22 dB increase in out-of-band emissions and a substantial risk of interference with adjacent channels.

Published in	International Journal of Wireless Communications and Mobile Computing (Volume 12, Issue 2)
DOI	10.11648/j.wcmc.20251202.15
Page(s)	119-130
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

HPA, PAPR, IBO, OTFS, BER, ACPR, Non-Linearity

References

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[2]	Wu, Y., Li, A., Beikmirza, M., Singh, G. D., Chen, Q., de Vreede, L. C. N., Alavi, M., & Gao, C. (2024). MP-DPD: Low-Complexity Mixed-Precision Neural Networks for En-ergy-Efficient Digital Predistortion of Wideband Power Amplifiers, IEEE Microwave and Wireless Technology Letters, https://doi.org/10.1109/LMWT.2024.3386330
[3]	Spano, C., Badini, D., Cazzella, L., & Matteucci, M. (2025). Local and Remote Digital Pre-Distortion for 5G Power Amplifiers with Safe Deep Reinforcement Learning. Sensors, 25(19), 6102. https://doi.org/10.3390/s25196102
[4]	Thys, C., Martinez Alonso, R., Lhomel, A., Fellmann, M., Deltimple, N., Rivet, F., & Pollin, S. (2024). Walsh-domain Neural Network for Power Amplifier Behavioral Modelling and Digital Predistortion. IEEE International Symposium on Circuits and Systems (ISCAS), https://doi.org/10.1109/ISCAS58744.2024.10557970
[5]	Kostrzewska, K., & Kryszkiewicz, P. (2024). Power Amplifier Modeling Framework for Front-End-Aware Next-Generation Wireless Networks. Electronics, Mdpi. https://doi.org/10.3390/electronics13091643
[6]	Galaviz-Aguilar, J. A., Vargas-Rosales, C., Cárdenas-Valdez, J. R., Aguila-Torres, D. S., Flores-Hernández, L. (2022). A Comparison of Surrogate Behavioral Models for Power Amplifier Linearization under High Sparse Data. Sensors, 22(19), 7461. https://doi.org/10.3390/s22197461
[7]	Kang, M., Lim, S., Park, Y. (2023). Deep Neural Network for the Behavioral Modeling of Memory Effects and Supply Dependency on 10-W Nonlinear Power Amplifiers. Journal of Electromagnetic Engineering and Science, 23(2), 134-138. https://doi.org/10.26866/jees.2023.2.r.152
[8]	Ortali, J., Mons, S., Reveyrand, T., Ngoya, E., & Mazière, C. (2025). Behavioral Modeling of RF Power Amplifiers Using a Time-Domain Characterization Approach. International Journal of Microwave and Wireless Technologies, 17(S6), 942-949. https://doi.org/10.1017/S175907872500042X
[9]	Tang, X., Wang, Z., Wang, Y. (2024). A Wideband Behavioral Model with Multiple States for RF Power Amplifier Based on Improved Recurrent Neural Network. 2024 2nd International Symposium of Electronics Design Automation (ISEDA), https://doi.org/10.1109/ISEDA62518.2024.10617555
[10]	Vimal, V., Thakur, P., Gupta, S., (2025). RF-Power Amplifier Modelling Using Inverse System Identification. Discover Computing, 28, 21. https://doi.org/10.1007/s10791-025-09522-4
[11]	Elakkiyachelvan, E., Kavitha, R., J., (2022). Space-Time Coding and LMMSE Receiver in OTFS Modulation. Proc. ITSPWC 2022. https://doi.org/10.4108/eai.14-5-2022.2318877
[12]	Sura H., Thamer M., Hassan F., (2025). A Performance and Evaluation of OTFS Modulation Systems Using Different High Mobility Channels. Int. J. Electronics & Telecommunication, 71(2), pp. 505-512. https://doi.org/10.24425-ijet.2025.153598
[13]	Obinna, O., Xutao, D., Agbotiname, L., Olamilekan, S., (2025). OTFS: A Potential Waveform for Space-Air-Ground Integrated Networks in 6G and Beyond. Telecom, 6(1), 19. https://doi.org/10.3390/telecom6010019
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[15]	Wei, L., Xuan, L., Jia, S., Lixin, L., Junfan, H., (2022). Underlying Security Transmission Design for OTFS Modulation. Sensors, 22(20), 7919. https://doi.org/10.3390/s22207919
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APA Style

Rakotonirina, H. B., Randrianandrasana, M. E. (2025). Effects of Power Amplifier Nonlinearity on OTFS Signals. International Journal of Wireless Communications and Mobile Computing, 12(2), 119-130. https://doi.org/10.11648/j.wcmc.20251202.15

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ACS Style

Rakotonirina, H. B.; Randrianandrasana, M. E. Effects of Power Amplifier Nonlinearity on OTFS Signals. Int. J. Wirel. Commun. Mobile Comput. 2025, 12(2), 119-130. doi: 10.11648/j.wcmc.20251202.15

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AMA Style

Rakotonirina HB, Randrianandrasana ME. Effects of Power Amplifier Nonlinearity on OTFS Signals. Int J Wirel Commun Mobile Comput. 2025;12(2):119-130. doi: 10.11648/j.wcmc.20251202.15

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@article{10.11648/j.wcmc.20251202.15,
  author = {Hariniony Bienvenu Rakotonirina and Marie Emile Randrianandrasana},
  title = {Effects of Power Amplifier Nonlinearity on OTFS Signals},
  journal = {International Journal of Wireless Communications and Mobile Computing},
  volume = {12},
  number = {2},
  pages = {119-130},
  doi = {10.11648/j.wcmc.20251202.15},
  url = {https://doi.org/10.11648/j.wcmc.20251202.15},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.wcmc.20251202.15},
  abstract = {Orthogonal Time Frequency Space (OTFS) modulation has emerged as a leading candidate for 6G wireless systems due to its exceptional robustness against high mobility and frequency-selective fading channels. However, its multicarrier structure inherently generates a high Peak-to-Average Power Ratio (PAPR), making OTFS signals highly susceptible to nonlinear distortions introduced by High Power Amplifiers (HPAs). This paper investigates the impact of HPA nonlinearity on OTFS transmission in terrestrial radio environments, using the Rapp model to characterize amplifier behavior. We evaluate key performance metrics including PAPR, Complementary Cumulative Distribution Function (CCDF), Bit Error Rate (BER), Adjacent Channel Power Ratio (ACPR), and amplifier efficiency under varying Input Back-Off (IBO) values (0.5 dB to 4 dB). Our results demonstrate that OTFS exhibits a significantly higher PAPR than conventional 16-QAM, necessitating a larger IBO to avoid saturation. While increasing IBO improves linearity and reduces BER particularly in realistic Rayleigh fading channels it comes at the cost of drastically reduced amplifier efficiency, dropping from 70% at IBO = 0 dB to below 15% at IBO = 6 dB. Furthermore, nonlinear amplification severely degrades spectral purity: ACPR deteriorates from -37 dB (before amplification) to -15 dB (after amplification), indicating a 22 dB increase in out-of-band emissions and a substantial risk of interference with adjacent channels.},
 year = {2025}
}

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TY  - JOUR
T1  - Effects of Power Amplifier Nonlinearity on OTFS Signals
AU  - Hariniony Bienvenu Rakotonirina
AU  - Marie Emile Randrianandrasana
Y1  - 2025/12/30
PY  - 2025
N1  - https://doi.org/10.11648/j.wcmc.20251202.15
DO  - 10.11648/j.wcmc.20251202.15
T2  - International Journal of Wireless Communications and Mobile Computing
JF  - International Journal of Wireless Communications and Mobile Computing
JO  - International Journal of Wireless Communications and Mobile Computing
SP  - 119
EP  - 130
PB  - Science Publishing Group
SN  - 2330-1015
UR  - https://doi.org/10.11648/j.wcmc.20251202.15
AB  - Orthogonal Time Frequency Space (OTFS) modulation has emerged as a leading candidate for 6G wireless systems due to its exceptional robustness against high mobility and frequency-selective fading channels. However, its multicarrier structure inherently generates a high Peak-to-Average Power Ratio (PAPR), making OTFS signals highly susceptible to nonlinear distortions introduced by High Power Amplifiers (HPAs). This paper investigates the impact of HPA nonlinearity on OTFS transmission in terrestrial radio environments, using the Rapp model to characterize amplifier behavior. We evaluate key performance metrics including PAPR, Complementary Cumulative Distribution Function (CCDF), Bit Error Rate (BER), Adjacent Channel Power Ratio (ACPR), and amplifier efficiency under varying Input Back-Off (IBO) values (0.5 dB to 4 dB). Our results demonstrate that OTFS exhibits a significantly higher PAPR than conventional 16-QAM, necessitating a larger IBO to avoid saturation. While increasing IBO improves linearity and reduces BER particularly in realistic Rayleigh fading channels it comes at the cost of drastically reduced amplifier efficiency, dropping from 70% at IBO = 0 dB to below 15% at IBO = 6 dB. Furthermore, nonlinear amplification severely degrades spectral purity: ACPR deteriorates from -37 dB (before amplification) to -15 dB (after amplification), indicating a 22 dB increase in out-of-band emissions and a substantial risk of interference with adjacent channels.
VL  - 12
IS  - 2
ER  -

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Author Information

Hariniony Bienvenu Rakotonirina

Department of Telecommunication, High School Polytechnic of Antsirabe, Antsirabe, Madagascar

Contact Email

http://orcid.org/0009-0004-5054-736X
Marie Emile Randrianandrasana

Department of Telecommunication, High School Polytechnic of Antsirabe, Antsirabe, Madagascar

Contact Email

http://orcid.org/0009-0007-2595-5857

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Plain Text BibTeX RIS

APA Style

Rakotonirina, H. B., Randrianandrasana, M. E. (2025). Effects of Power Amplifier Nonlinearity on OTFS Signals. International Journal of Wireless Communications and Mobile Computing, 12(2), 119-130. https://doi.org/10.11648/j.wcmc.20251202.15

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ACS Style

Rakotonirina, H. B.; Randrianandrasana, M. E. Effects of Power Amplifier Nonlinearity on OTFS Signals. Int. J. Wirel. Commun. Mobile Comput. 2025, 12(2), 119-130. doi: 10.11648/j.wcmc.20251202.15

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AMA Style

Rakotonirina HB, Randrianandrasana ME. Effects of Power Amplifier Nonlinearity on OTFS Signals. Int J Wirel Commun Mobile Comput. 2025;12(2):119-130. doi: 10.11648/j.wcmc.20251202.15

Copy | Download

@article{10.11648/j.wcmc.20251202.15,
  author = {Hariniony Bienvenu Rakotonirina and Marie Emile Randrianandrasana},
  title = {Effects of Power Amplifier Nonlinearity on OTFS Signals},
  journal = {International Journal of Wireless Communications and Mobile Computing},
  volume = {12},
  number = {2},
  pages = {119-130},
  doi = {10.11648/j.wcmc.20251202.15},
  url = {https://doi.org/10.11648/j.wcmc.20251202.15},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.wcmc.20251202.15},
  abstract = {Orthogonal Time Frequency Space (OTFS) modulation has emerged as a leading candidate for 6G wireless systems due to its exceptional robustness against high mobility and frequency-selective fading channels. However, its multicarrier structure inherently generates a high Peak-to-Average Power Ratio (PAPR), making OTFS signals highly susceptible to nonlinear distortions introduced by High Power Amplifiers (HPAs). This paper investigates the impact of HPA nonlinearity on OTFS transmission in terrestrial radio environments, using the Rapp model to characterize amplifier behavior. We evaluate key performance metrics including PAPR, Complementary Cumulative Distribution Function (CCDF), Bit Error Rate (BER), Adjacent Channel Power Ratio (ACPR), and amplifier efficiency under varying Input Back-Off (IBO) values (0.5 dB to 4 dB). Our results demonstrate that OTFS exhibits a significantly higher PAPR than conventional 16-QAM, necessitating a larger IBO to avoid saturation. While increasing IBO improves linearity and reduces BER particularly in realistic Rayleigh fading channels it comes at the cost of drastically reduced amplifier efficiency, dropping from 70% at IBO = 0 dB to below 15% at IBO = 6 dB. Furthermore, nonlinear amplification severely degrades spectral purity: ACPR deteriorates from -37 dB (before amplification) to -15 dB (after amplification), indicating a 22 dB increase in out-of-band emissions and a substantial risk of interference with adjacent channels.},
 year = {2025}
}

Copy | Download

TY  - JOUR
T1  - Effects of Power Amplifier Nonlinearity on OTFS Signals
AU  - Hariniony Bienvenu Rakotonirina
AU  - Marie Emile Randrianandrasana
Y1  - 2025/12/30
PY  - 2025
N1  - https://doi.org/10.11648/j.wcmc.20251202.15
DO  - 10.11648/j.wcmc.20251202.15
T2  - International Journal of Wireless Communications and Mobile Computing
JF  - International Journal of Wireless Communications and Mobile Computing
JO  - International Journal of Wireless Communications and Mobile Computing
SP  - 119
EP  - 130
PB  - Science Publishing Group
SN  - 2330-1015
UR  - https://doi.org/10.11648/j.wcmc.20251202.15
AB  - Orthogonal Time Frequency Space (OTFS) modulation has emerged as a leading candidate for 6G wireless systems due to its exceptional robustness against high mobility and frequency-selective fading channels. However, its multicarrier structure inherently generates a high Peak-to-Average Power Ratio (PAPR), making OTFS signals highly susceptible to nonlinear distortions introduced by High Power Amplifiers (HPAs). This paper investigates the impact of HPA nonlinearity on OTFS transmission in terrestrial radio environments, using the Rapp model to characterize amplifier behavior. We evaluate key performance metrics including PAPR, Complementary Cumulative Distribution Function (CCDF), Bit Error Rate (BER), Adjacent Channel Power Ratio (ACPR), and amplifier efficiency under varying Input Back-Off (IBO) values (0.5 dB to 4 dB). Our results demonstrate that OTFS exhibits a significantly higher PAPR than conventional 16-QAM, necessitating a larger IBO to avoid saturation. While increasing IBO improves linearity and reduces BER particularly in realistic Rayleigh fading channels it comes at the cost of drastically reduced amplifier efficiency, dropping from 70% at IBO = 0 dB to below 15% at IBO = 6 dB. Furthermore, nonlinear amplification severely degrades spectral purity: ACPR deteriorates from -37 dB (before amplification) to -15 dB (after amplification), indicating a 22 dB increase in out-of-band emissions and a substantial risk of interference with adjacent channels.
VL  - 12
IS  - 2
ER  -

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