Порівняння Ансамблів Кодових Множин, Синтезованих На Основі Декількох Модулів З Ансамблями, Реалізованими На Основі Таймерних Сигнальних Конструкцій

Method of Accuracy Increase in Radio Control Systems With Orthogonal Frequency Multiplexising at the Consideration of the Timer Signal Constructions Use

“…The task of determining the parameters of the OFDM signal with a minimum probability of a bit error is reduced to a typical optimization problem. The system of equations for solving the optimization problem has the form [5][6][7]:…”

“…The method of selecting the parameters of the OFDM signal, the algorithm of which is presented in fig. 1, consists of the following steps [7,8].…”

“…Due to Doppler dispersion, as well as errors in the evaluation of the frequency of the transmitter on the receiving side, the orthogonality between the subcarriers is violated. In a number of papers, studies have been conducted on the equivalent loss in the required signal / noise ratio for a given Doppler dissipation, as well as the error of estimating the carrier at the reception [4][5][6][7][8][9]. For short-wave (SW) and ultra short-wave (USW) channels, the equivalent loss in signal / noise of no more than 0.5 dB Doppler scattering should not exceed 2-3% of the distance between subcarriers.…”

“…That is, from this point of view, the distance between subcarriers needs to be minimized. For the SW channel, the distance of 50 Hz is the maximum allowable, since larger values of the distance between the carriers lead to a significant distortion of the channel parameters, resulting in a distortion of the symbol [6,7]. Another limitation on the length of a character is the assumption that the channel parameters must be constant over the length of the character.…”

“…At this stage, the use of the methods presented in [4,5,7,9], the state of the multichannel communication channel was evaluated and its transfer characteristic was determined. Thus, we can draw the following conclusions:…”