Siberian State University of Telecommunications and Informatics

This article discusses a method for transmitting information over a wireless channel other than a radio channel. A wireless optical data transmission system implemented using wavelength division multiplexing technology is considered. The spectral efficiency modulation formats, optical system capacities, and signal-to-noise ratios in multiservice optical telecommunications networks using wavelength division multiplexing technology are analyzed. The purpose of this paper is to explore methods for calculating the performance characteristics wireless optical cellular networks based on a DWDM system. The operating principles wireless optical network nodes and the impact atmospheric factors and turbulence on transmission systems are examined. A study of wireless optical networks proposed a new approach for calculating their performance indicators. The calculation methods considered take into account the efficiency modulation methods, the transmission range optical signals, the received signal power taking into account atmospheric factors, and the frequency efficiency the optical transmission system.

The article is devoted to the study of stylistic features of the Lake School poets. The research methodology included several stages. Initially, a corpus of texts was formed, consisting of 99 poetic works by three authors belonging to this literary trend. At this stage, preliminary text processing and extraction of relevant features were carried out. Further, a model of text vectors space was applied to represent poetic texts. In order to analyze and identify the unique stylistic characteristics of each poet, a feature matrix was applied, analyzed using five common machine learning algorithms, including the support vector machine (SVM) method and Random Forest. To solve the problem of data imbalance, SMOTE (Synthetic Minority Oversampling Technique) was applied, which improved classification accuracy. In particular, the modified SVM model achieved an F1 measure exceeding 90 % in the task of recognizing the authorship of poetic texts. At the final stage of the study, the complex stylistic characteristics of the poetry by the three authors were compared, which revealed significant differences in their individual styles. The results of the study provide valuable information for further research in the field of poetry stylistic features.

A new approach to the problem of error correction in communication channels is proposed, in which the input sequence is transformed in such a way that the interdependence of symbols is significantly increased. Then, after the sequence is transmitted over the channel, this property is used for error correction so that the remaining error rate is significantly reduced. The complexity of encoding and decoding is linear.

В статье анализируются факторы, влияющие на организацию спутниковой связи в условиях высоких широт России. На основании рекомендаций МСЭ-R в области распространения радиоволн проведена оценка потерь энергии сигнала в Арктике как в свободном пространстве, так и с учетом атмосферного слоя. Расчеты проведены для углов места от 1 до 20 градусов в С- и Ku-диапазонах с учетом климатических факторов, характерных для Крайнего Севера: интенсивность осадков и общий столбчатый объем жидкой воды в атмосфере. Результаты расчетов представлены зависимостями от угла места, что позволяет использовать полученные данные для оценки энергетического бюджета спутниковых линий связи в критических условиях высоких широт. Также рассмотрены потери энергии сигнала из-за неточности наведения антенн, которые определяются шириной диаграммы направленности антенн и внешними дестабилизирующими факторами, одним из которых в условиях Крайнего Севера является повышенная ветровая нагрузка. Дана оценка шумовых параметров приемной земной станции, причем в условиях малых углов места шумовая температура антенны определяется шумами излучения атмосферы, а именно влиянием газов атмосферы, облачности и осадков. Результаты представлены в виде зависимости шумовой температуры от угла места для в С- и Ku-диапазонов на основе расчетов потерь в атмосфере. Проведенное исследование планируется использовать при разработке рекомендаций по энергетическому расчету спутниковых линий в Арктических регионах России на границе зоны видимости геостационарных спутников. The article analyzes the factors influencing the organizationof satellite communications in the conditionsof high latitudes of Russia. Using ITU-R recommendations on radio wave propagation, an assessment of signal energy losses is provided for low elevation angles in free space and in the atmospheric layer. Calculations were performed for elevation angles from 1 to 20 degrees in the C- and Ku-bands, taking into account climatic factors characteristic of the Far North: precipitation intensity and total integrated liquid water content in the atmosphere. The calculation results are presented as dependencies on the elevation angle, which allows the obtained data to be used for assessing the energy budget of satellite communication links in critical high-latitude conditions. Signal energy losses due to antenna pointing inaccuracies are also considered, which are determined by the antenna's beamwidth and external destabilizing factors, one of which in the Far North conditions is increased wind load. An assessment of the noise parameters of a receiving earth station is provided, where under low elevation angle conditions, the antenna noise temperature is determined by atmospheric radiation noise, specifically the influence of atmospheric gases, cloudiness, and precipitation. The results are presented as the dependence of noise temperature on the elevation angle for the C- and Ku-bands, based on calculations of atmospheric losses. The conducted research is planned to be used in the development of recommendations for the energy calculation of satellite links in the Arctic regions of Russia at the edge of the visibility zone of geostationary satellites.

Предложены универсальные аналитические выражения для расчёта показателя качества (Q-фактора) оптических амплитудно-фазовых канальных сигналов при организации связи между центрами обработки данных (DC- Data Center) по технологии мультиплексирования СО-OFDM (Coherent Orthogonal Frequency Division Multiplexing). Рассмотрена однопролётная волоконно-оптическая система передачи с оптическим усилителем, расположенным на приёмной стороне, и использованием поляризационного мультиплексирования для передачи OFDM-сигналов. Полученные формулы учитывают одновременное влияние нелинейных фазовых искажений, возникающих в волокне, и шумов усиленной спонтанной эмиссии. Формулы позволяют оценить помехоустойчивость отдельных сигнальных точек созвездия M-QAM в зависимости от параметров системы передачи, не прибегая к ресурсоёмкому имитационному моделированию. Вычисления помехоустойчивости поляризационно-мультиплексированных 16-QAM канальных сигналов показали возможность организации соединения между DC по стандартному одномодовому волокну на расстоянии 80 км с суммарной скоростью передачи данных 32 Тбит/с. Universal analytical expressions are proposed for calculating the quality factor (Q-factor) of optical amplitude-phase channel signals for data centerinterconnection (DCI) using Coherent Orthogonal Frequency Division Multiplexing (CO-OFDM). A single-span fiber-optic transmission system with an optical amplifier located at the receiving end and using polarization multiplexing for transmitting OFDM signals is considered. The resulting formulas take into account the simultaneous effects of nonlinear phase distortions occurring in the fiber and amplified spontaneous emission noise. These formulas enable the noise immunity of individual signal points in the M-QAM constellation to be estimated depending on the transmission system parameters, without resorting to resource-intensive simulation modeling. Calculations of the noise immunity of polarization-multiplexed 16-QAM channel signals showed the possibility of organizing a connection between Data Centers over a standard single-mode fiber over a distance of 80 km with a total data transfer rate of 32 Tbit/s.