N.A. Vorobev1, P.V. Luferchik2, A.N. Konev3, D.V. Chashchin4

1–4 JSC «SPE «Radiosvyaz» (Krasnoyarsk, Russia)

1 vorobev_na@krtz.su, 2 lpv@krtz.su, 3 konev_an@krtz.su, 4 chaschin_dv@krtz.su

It is well-established that inter-symbol interference (ISI) degrades signal reception during information transmission over a tropospheric radio channel. To mitigate this issue at the receiver, adaptive equalizers are commonly employed. While fractionally-spaced algorithms can be used for more complex channels, they come with higher computational complexity. In contrast, symbol-spaced equalizers offer significantly lower computational complexity, allowing their implementation in real systems. Therefore, it is necessary to evaluate the effectiveness of symbol-spaced equalizers in tropospheric communication systems. The objective of this study is to identify the most effective structure of a symbol-spaced adaptive equalizer for deployment in tropospheric radio communication systems. The results indicate that a symbol-spaced adaptive feed-backward equalizer, based on the Recursive Least Squares (RLS) algorithm, can nearly neutralize the multipath effect under the examined tropospheric channel conditions. The optimal value achieved for the equalizer's average mean square error was -47,9 dB, which is 2,1 dB above the noise level in an Additive White Gaussian Noise (AWGN) channel. In comparison, the best average mean square error value for the equalizer based on the Least Mean Squares (LMS) algorithm was approximately -30,1 dB. This represents an improvement of around 17,8 dB when using the RLS algorithm over the LMS algorithm. Utilizing the most effective adaptive symbol-spaced equalizer structure allows its implementation in real systems on Field-Programmable Gate Arrays (FPGAs) and ensures optimal equalization performance.

Vorobev N.A., Luferchik P.V., Konev A.N., Chashchin D.V. Research on the effectiveness of using symbol-spaced adaptive equalizers in troposcatter communication systems. Achievements of modern radioelectronics. 2025. V. 79. № 2. P. 52–58. DOI: https://doi.org/10.18127/j20700784-202502-06 [in Russian]

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