A.R. Bestugin1, S.V. Dvornikov2, S.S. Dvornikov3, I.A. Kirshina4, S.V. Selivanov5

1-4 Saint-Petersburg State University of Aerospace Instrumentation (St. Petersburg, Russia)

2,3 Military Academy of Communications n.a. Marshal of the Soviet Union S.M. Budyonny (St. Petersburg, Russia)

5 JSC “Aerospace Defense Concern Almaz-Antey” (St. Petersburg, Russia)

1 fresguap@mail.ru; 2 practicdsv@yandex.ru; 3 dvornic92@mail.ru; 4 ikirshina@mail.ru; 5 selivanovi@yandex.ru

Currently, VSAT (Very Small Aperture Terminal) networks are most widely used in areas with poorly developed telecoms infrastructure. Thus, according to the consulting agency Nothern Sky Reseach, by the beginning of 2019 there were more than 7.5 million active VSAT users. At the same time, over 130 thousand VSAT terminals were registered on the territory of the Russian Federation.

Thus, VSAT networks are increasingly being used, including for organising telephone communications.

At the same time, the simplicity of VSAT networks based on retransmission of signals between subscribers via satellites without on-board processing has caused their vulnerability to mutual interference of unintentional nature. Therefore, the purpose of this work is to assess the noise immunity of telephone communication lines of typical subscriber terminals operating in accordance with ITU-R Recommendation G.721.

The conducted research allows us to draw the following conclusion. Despite a high enough level of EVC, provided by cascade use of convolutional code and Reed-Solomon code, the general noise immunity of telephone communication lines in VSAT networks is rather low. While the length of the interval of noise immunity is 7.5 dB. 

Applied measures aimed at increasing noise immunity reception are effective only in conditions of Gaussian noise of low intensity. In the case of mutual interference, the power level of which will not exceed 1/16 of the power of the useful signal, the reliability of reception on the telephone lines in VSAT networks will be at the limit level.

Increase of noise immunity for subscriber terminals can be provided by transition to the use of broadband signals, including on the basis of application of wide-basis signals of linear frequency modulation.

At the same time, taking into account the principle of satellite-repeater operation without on-board signal processing, such transition will require modernisation of only the modem part of subscriber terminals

Bestugin A.R., Dvornikov S.V., Dvornikov S.S., Kirshina I.A., Selivanov S.V. Interference immunity of subscriber terminals of very small aperture terminal in telephony mode. Radiotekhnika. 2024. V. 88. № 4. P. 142−148. DOI: https://doi.org/10.18127/j00338486-202404-14 (In Russian)

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