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Документ The method of increasing the immunity of communication systems(Національний технічний університет "Харківський політехнічний інститут", 2019) Mahdi, Qasim AbboodNowadays, due to a severe shortage of radio resources of communication systems, which is caused by an increase in the number of subscribers of cellular communication systems, an increase in demand for information resources, which in turn leads to the search for new technological approaches to its solution. The analysis of well-known scientific works carried out in the article showed that the technology of orthogonal frequency multiplexing almost completely exhausted the possibility of its improvement. One of the ways to improve the efficiency of radio resource use of communicationsystems is using spectrally effective signals. This article has developed a methodology for improving the noise immunity of communication systems. The essence of this methodis to switch the modes of communication in the session mode, depending on the signal- interference situation in the channel, with the subsequent adjustment of the parameters of the communication channel by selecting the optimal signal-code structures. In the course of the research, the main provisions of the theory of communication, the theory of signal-code structures, the theory of noise immunity, as well as general scientific methods such as analysis and synthesis were used. A distinctive feature of this methodfrom the known,which determines its novelty are:the possibility of changing themode of operation in the session mode; the modes of operation of this technique are signals with orthogonal frequency multiplexing and spectral-effective signals. The proposed technique provides 15–18% more noise immunity compared with the known methods of generating spectral-effective signals, but 10–12% less noise immunity compared to the orthogonal signals.