radioelectronicsИзвестия высших учебных заведений России. РадиоэлектроникаJournal of the Russian Universities. Radioelectronics1993-89852658-4794Saint Petersburg Electrotechnical University10.32603/1993-8985-2018-21-3-23-34radioelectronics-231Research ArticleРАДИОТЕХНИЧЕСКИЕ СРЕДСТВА ПЕРЕДАЧИ, ПРИЕМА И ОБРАБОТКИ СИГНАЛОВRADIO ELECTRONIC FACILITIES FOR SIGNAL TRANSMISSION, RECEPTION AND PROCESSINGОптимизация итерационных алгоритмов оценки состояния канала связи в системе множественного доступа с разреженным кодированиемOptimization of Iterative Channel State Estimation Algorithms in SCMA SystemКлиментьевВ. П.KlimentyevV. P.

Климентьев Вячеслав Петрович – магистр техники и технологий по направлению "Радиотехника" (2013), аспирант кафедры теоретических основ радиотехники . Автор 18 научных работ. Сфера научных интересов – цифровая связь; цифровая обработка сигналов.

ул. Профессора Попова, д. 5, Санкт-Петербург, Россия, 197376.

Vyacheslav P. Klimentyev – Master’s Degree in radio engineering (2013), postgraduate student of the Department of Theoretical Fundamentals of Radio Engineering of Saint Petersburg Electrotechnical University "LETI". The author of 18 scientific publications. Area of expertise: signal processing; digital communications. 

5, Professor Popov Str., 197376, St. Petersburg.

vklimentyev@gmail.comСергиенкоА. Б.SergienkoA. B.

Сергиенко Александр Борисович – кандидат технических наук (1995), доцент (1998) кафедры теоретических основ радиотехники член IEEE (1998). Автор 102 научных работ. Сфера научных интересов – обработка сигналов; цифровая связь.

ул. Профессора Попова, д. 5, Санкт-Петербург, Россия, 197376.

Alexander B. – PhD in Engineering (1995), Associate Professor (1998), Professor (2018) of the Department of Theoretical Fundamentals of Radio Engineering of Saint Petersburg Electrotechnical University "LETI", IEEE member (1998). The author of 102 scientific publications. Area of expertise: signal processing; digital communications.

5, Professor Popov Str., 197376, St. Petersburg

sandy@ieee.orgСанкт-Петербургский государственный электротехнический университет “ЛЭТИ” им. В. И. Ульянова (Ленина).РоссияSaint Petersburg Electrotechnical University "LETI".Russian Federation201828062018032334Copyright © Климентьев В.П., Сергиенко А.Б., 20182018Климентьев В.П., Сергиенко А.Б.Klimentyev V.P., Sergienko A.B.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://re.eltech.ru/jour/article/view/231

Проведена оптимизация итерационных алгоритмов оценки состояния канала в системе множественного доступа с разреженным кодированием, направленная на снижение вычислительных затрат приемника. Установлено, что при отношении "сигнал/шум" (ОСШ), меньшем 10 дБ, достаточно одной итерации алгоритма, а увеличение числа итераций не приводит к росту спектральной эффективности (СЭ). Моделирование продемонстрировало возможность обоснованного выбора общего числа итераций декодера и их распределения между различными этапами оценки канала. Для некодированной системы предложена последовательная итерационная переоценка канала, а также способы уменьшения вычислительных затрат при ее выполнении. В кодированной системе при малом ОСШ обеспечиваемые данным алгоритмом параметры СЭ практически не отличаются от параметров метода, в котором для оценки используются только пилот-сигналы. Даны рекомендации по размещению символов данных и пилот-сигналов в блоках ресурсов, позволяющие увеличить СЭ системы.

Optimization of iterative algorithms for channel state estimation in a sparse coding multiple-access system (SCMA) is performed to reduce computational costs of the receiver. It is shown that when a signal-to-noise ratio (SNR) does not exceed 10 dB, one iteration of the algorithm is sufficient, and an increase in the number of iterations does not lead to an increase in spectral efficiency. Simulation demonstrates a possibility of a reasonable choice of the total number of decoder iterations and their distribution between different stages of the channel estimation. For an uncoded system, iterative re-estimation of the channel is proposed, as well as ways to reduce computational costs during its calculation. In the coded system, at a low SNR the achieved spectral efficiency values are approximately similar to those with pilot-only channel estimation. The article provides recommendations for the placement of data symbols and pilot signals in re-source blocks to increase the system spectral efficiency.

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The authors declare that there are no conflicts of interest present.