ОПРЕДЕЛЕНИЕ ЗАНЯТОСТИ КВ-РАДИОКАНАЛОВ С ПОЛОСАМИ 3…24 кГц ДЛЯ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ ПЕРЕДАЧИ ИНФОРМАЦИИ
Authors: Иванов Д.В. , Иванов В.А. , Рябова Н.В. , Бельгибаев Р.Р. 
Published: February 2025

Для повышения эффективности передачи информации в КВ-диапазоне исследована задача определения занятости радиоканалов с полосами 3…24 кГц. Разработаны алгоритмы и методики оценки занятости радиоканалов при обработке экспериментальных уровней шума в КВ-диапазоне. На базе технологии SDR разработан лабораторный образец программно-аппаратного комплекса мониторинга спектра помех. Получены результаты анализа влияния геофизических факторов на загруженность КВ-радиоканалов с различной полосой частот.
Introduction. Currently, there is a rise in HF communications due to the new benefits, including software-defined radio (SDR), embedded encryption, digital communications technology, and cognitive radio (CR). State-of-the-art HF radio applications are employed in civil, industrial, military, defense and public security fields, from maritime transport to humanitarian operations in remote areas. One of the disadvantages of HF communication is high sensivity to man-made interferences and the dependence of interferences and channel characteristics on the variability of the ionosphere over geophysical time. Since the efficiency of communication systems is defined by the ratio of the signal energy to the spectral density of interferences, therefore, without regard the energy margin of the communication system (in fact, the system itself), the spectral power density of the interferences in the channel at the allocated frequencies remains the main factor that affects the quality of communication. A more promising approach implies opting the least occupied channels. At the same time, the problem of estimating the channel availability according to the propagation parameters remains topical. The aim of the research: development of algorithms and methods for estimating the occupancy of a radio channels with the use of data on the noise level in the HF band for adapting the digital HF communication system according to sounding data, as well as studying their efficiency in determining the occupancy of radio channels with 3...24 kHz bandwidth. Research methods. There is applied cognitive radio technology to effectively choose the operating frequencies, the type of modulation and the power of the communication signal. Application of software-defined radio technology allows to create multipurpose devices by means of software that can solve the problems of diagnosing contiguous radio channels, in addition to communication objectives. Findings. To estimate the occupancy of wideband channels in the HF band, the methods of analysis and interpretation of spectral data was scientifically argued. On the basis of SDR technology, a laboratory facility of a software hardware complex was developed for monitoring the interference environment in the HF band with a resolution of 3, 6, 12 and 24 kHz. It was experimentally found that the busiest channels in the daytime for Yoshkar-Ola belong to the frequency bands 3–9 MHz and 26–28 MHz. The channel occupancy decreased with an increase in the operating frequency. It was experimentally found that occupancy of NVIS channels increases. The increase in the occupancy of radio channels in the band 26–28 MHz is caused by the operation of civil services. The analysis of the findings showed that in the summer period there was an increase in the occupancy of radio channels in the band 5–9 MHz compared to the spring period. This is caused by the increase in the critical frequency of the F2 layer and the reception of remote radio equipment. Low occupancy of radio channels in the band 4–8 MHz allows to suggest the feasibility of organizing wideband communication over several adjacent or non-adjacent 3 kHz channels for tactical NVIS communication. Conclusion. Experimental measurements showed that it is feasible to implement wideband HF communication with bandwidth up to 24 kHz, that allows to significantly increase the data rates.