Information and telecommunication sciences: international research journal, Vol. 13, N. 2
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Перегляд Information and telecommunication sciences: international research journal, Vol. 13, N. 2 за Ключові слова "621.396.1"
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Документ Відкритий доступ Evaluation of the multipath effect on the quality of radio communication in the technological range IEEE 802.11xx(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Uryvsky, Leonid; Solianikova, ValeriiaBackground. As a result of the rays’ reflection from buildings, from the surface of the Earth or from horizontal boundaries between different layers of the atmosphere, occur multipath effects that cause fast fading, which degrades the quality of service. Objective. The purpose of the paper is to determine the multipath effect on the signal-to-noise ratio in a wireless communication channel. Compare the results obtained for a communication channel at operating frequencies of the IEEE 802.11xx standard: 5 GHz and 2.4 GHz. Methods. The useful signal powers and the total interference powers for a communication channel with multipath are calculated. The signal-to-noise ratio for such a channel is compared at operating frequencies of 5 GHz and 2.4 GHz. Results. The results of the study showed that the higher the frequency of the carrier of the wireless radio link, the less pronounced the effect of multipath is. The frequency rating significantly affects the quality of communication in multipath conditions. In this case, lowering the frequency significantly improves the reception condition outside of multipath effect. However, it deteriorates significantly due to the effects of rays reflected from the Earth's surface. In the considered case, the useful signal power in the 2.4 GHz band is 4.2 times higher; at the same time, the power of reflected interference is 19 times higher than in the 5 GHz band. Conclusions. Suggested model makes it possible to determine the effect of interference power in the ranges traditionally assigned in IEEE 802.11xx technology, specifically 2.4 GHz and 5 GHz.Документ Відкритий доступ New Barker’s composite codes as modulation signals in broadband communication systems(National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", 2022) Maksymov, Volodymyr; Noskov, Vyacheslav; Khrapovytsky, IgorBackground. Currently noise-like signals (NLS) are widely used and provide high level of jamming immunity and security in broadband communication systems (BСS) when transmitting confidential information in an open radio channel, especially in emergencies. Increasing the efficiency of the NLS is possible when using more advanced code structures. Objective. The purpose of this research is to study new Barker’s composite codes as modulation signals in broadband communication systems. Method. Simulation modeling based on MatLab software package and analytical calculation methods are used. Results. Modeling in the MatLab software package showed the possibility for using new Barker’s composite codes as modulation signals in direct spread spectrum systems but efficiency depends on code words length as well as type synchronization signal. Conclusions. Analysis of research results shows that the new Barker composite codes 21a, 33a, 49, 77a, 121 can be effectively used as modulation code words in broadband systems with direct spectrum expansion.