Методы оценки пропускной способности с учётом требуемой помехоустойчивости фазовой радиотехнической системы с последовательной передачей информации в среднеширотных узкополосных КВ-каналах связи
Authors: Лернер И.М. 
Published: February 2025

В работе представлены методы оценки помехоустойчивости радиотехнической системы с последовательной передачей информации при воздействии аддитивного белого гауссовского шума, набега фазы, обусловленного малым доплеровским расширением спектра, неидеальностью аналогового цифрового преобразователя, дисбалансом I/Q, нестабильностью восстановления несущей частоты принимаемого сигнала, для радиотехнической системы с последовательной передачей информации. Разработан аналитический метод оценки разрешающего времени для огибающей при использовании многопозиционного фазоманипулированного сигнала. Показан выигрыш по пропускной способности, более чем 25 % и по помехоустойчивости 5,93 дБ при BER=10-3 за счёт применения теории разрешающего времени по отношению к результатам, достигаемым в стандарте STANAG 4539 при использовании фазоманипулированного сигнала с 4 дискретными состояниями в парциальном 3 кГц КВ-канале при задержке между лучами 185 мкс и доплеровским расширением спектра 0,5 Гц.

Currently, high attention is focused on the application of adaptive control of operating modes or the use of adaptive methods for signal reception and processing in the field of developing advanced radio engineering data transmission systems (ReDTS). Such approach is promising for increasing systems capacity, especially for those that operate under conditions of dynamically changing frequency selective propagation medium. The topic primarily concerns ReDTS operating over ionospheric HF communication channels, for which the problem of increasing the capacity is a key factor in their efficiency. One of the approaches that can increase the capacity of the above systems is the use of the theory of resolution time, which allows one to control the operating modes of data transmission systems. First off, it is reasonable to show the approach for serial ReDTS, which are currently widely used in practice. The goal of this paper is to create methods for estimating the capacity accounting the required noise immunity of a phase serial ReDTS based on the theory of resolution time (TRT) for data transmission in HF ionospheric communication channels with a low Doppler spread. To achieve this goal, the following problems were solved: 1) there were derived analytical expressions that allow to estimate the required SNR for the specified class of phase ReDTS based on TRT for a given value of the bit error rate and the presence of destabilizing factors (phase incursion due to low Doppler spread, non-ideal operation of subsystems of the serial ReDTS); 2) an analytical method for estimating the resolution time for the envelope using a PSK-n-signal has been developed; 3) estimates of noise immunity and capacity for a typical decameter ionospheric communication channel of 3 kHz width were obtained and compared with similar characteristics achieved in the STANAG 4359. The solution of these problems was carried out by means of mathematical modeling in the Matlab environment using previously developed author's software, as well as the development of appropriate analytical methods using previously developed models. The findings: 1) methods for estimating the noise immunity of the serial ReDTS based on the TRT have been developed; 2) an analytical method for estimating the resolution time for an envelope using a PSK-n-signal for data transmission has been created, which has the same limitations that are inherent in the previously developed method for estimating the resolution time for this type of signal; 3) the estimates obtained for the serial ReDTS based on the TRT, which uses the QPSK, showed an increase in throughput by 25.8% compared to the results obtained in the framework of the STANAG 4539 standard for a 3 kHz channel; in this case, the gain in noise immunity varies from 5.93 dB to 6.09 dB, depending on the design of the subsystems of serial ReDTS.