A. M. Fominykh1, P. V. Luferchik2, A. A. Komarov3, A. V. Arkhipov4, N. A. Vorobev5, E. V. Smirnov6
1–6 JSC SPE «Radiosvyaz» (Krasnoyarsk, Russia)

1 filiphin@icloud.com, 2 lpv@krtz.su, 3 komarov_aa@krtz.su, 4 archipov_av@krtz.su, 5 vorobev_na@krtz.su, 6 smirnov_ev@krtz.su

The article addresses the issue of increasing the autonomy of portable satellite communications stations. One of the ways to enhance the autonomy of portable communication stations is to use a power amplifier in saturation mode instead of linear mode to improve efficiency. However, when using an amplifier in saturation mode, it is necessary to choose an appropriate type of modulation to minimize the level of out-of-band emissions (which leads to a deterioration in demodulation accuracy). In this regard, studies have been conducted to examine the effect of amplifier parameters in saturation mode on the quality of the transmitted signal. A software-hardware platform has been developed to conduct the studies, which investigated both standard modulations and modulations with nonlinear filtering. The studies have revealed that, in saturation mode, the effect of changes in input power on output power is minimal, but the signal spectrum deteriorates due to increased nonlinear distortions, especially in signals with a non-zero peak factor. The studies have also showed that using OQPSK modulation with a Nyquist filter and roll-off factor of 90% provided the best results in terms of both spectral and energy efficiency among the considered types of modulation for the power amplifier under investigation, minimizing distortions and maintaining high signal fidelity.

Fominykh A.M., Luferchik P.V., Komarov A.A., Arkhipov A.V., Vorobev N.A., Smirnov E.V. Comparative analysis of different types of modulation in satellite communications systems with class AB amplifiers operating in the saturation mode. Antennas. 2024. № 6. P. 45–50. DOI: https://doi.org/10.18127/j03209601-202406-04 (in Russian)

1. Joung J., Ho C.K., Adachi K., Sun S. A survey on power-amplifier-centric techniques for spectrum- and energy-efficient wireless communications. IEEE Communications Surveys & Tutorials. 2015. V. 17. № 1. P. 315–333. DOI: 10.1109/COMST.2014.2350018.
2. Sheng C., Bi X., Xu Q. A linear high-efficiency distributed power amplifier utilizing class-AB and inverse-class-C complementary structure. IEEE Transactions on Circuits and Systems I: Regular Papers. 2024. P. 1–11. DOI: 10.1109/TCSI.2024.3349558.
3. An J., Song Z. A new FQPSK with ideal BER performance. 7th International Conference on Wireless Communications, Networking and Mobile Computing. Wuhan, China. 2011. P. 1–3.
4. Xie Zh., Zhang G., Zhu H. A novel waveform for FQPSK modulation. 11th IEEE Singapore International Conference on Communication Systems. November, 2008. P. 851–854.
5. Feher K. FQPSK: a superior modulation technique for mobile and personal communications. IEEE Transactions on Broadcasting. 1993. V. 39. № 2. P. 288–294.
6. Bondarenko V.N., Luferchik A.V., Ovchinnikov N.N. Analiz vliyaniya fazovogo shuma geterodina na pomekhoustojchivost' priema signalov s amplitudno-fazovoj modulyatsiej. Uspekhi sovremennoj radioelektroniki. 2023. T. 77. № 12. S. 124–130. (in Russian)