Методи формування ансамблів складних сигналів для когнітивних телекомунікаційних систем

Abstract

UA: Вперше розроблено метод перестановок частотних елементів сигналів шляхом повного перебору, який дозволяє збільшити об’єм ансамблів складних сигналів за рахунок повного перебору сигналів, отриманих на основі виділення частотних елементів з подальшим вибором оптимального варіанта перестановок. Удосконалено метод формування ансамблів складних сигналів, отриманих шляхом перестановки часових інтервалів послідовностей на основі центрованого ряду, який відрізняється від відомих формуванням центрованого ряду на основі середнього значення максимальних викидів бічних пелюсток ФВК, застосування якого дозволяє знизити рівень завад множинного доступу і збільшити об’єм ансамбля. Отримав подальшого розвитку метод формування ансамблів складних сигналів на основі послідовностей з покращеними взаємокореляційними властивостями, отриманими шляхом смугової фільтрації з перестановками, реалізований на основі виділенні зі спектра послідовностей рівних смуг з наступним перенесенням до спільної області частот і подальшим застосуванням перестановок, що дозволяє значно збільшити об’єм ансамблів складних сигналів, при цьому взаємокореляційні властивості сигналів задовольняють умову мінімальної подоби, і такі сигнали можуть застосовуватися в когнітивних телекомунікаційних системах.

EN: The dissertation research is devoted to the development of the formation methods of complex signal ensembles for cognitive telecommunication systems, which allow increasing the volume of ensembles while providing a low level of multiple access interference. For the first time, a method of permutation of frequency elements of signals by complete search was developed, which allows increasing the volume of complex signals ensembles by m times, where m is the number of permutations of frequency elements. The essence of the method is to compare the values of the maximum emissions of the side lobes of the CСF of signals, formed by frequency filtering of different output sequences in different frequency bands. If in the process of calculations, a signal is detected, the interaction with which violates the compliance of the condition of minimum similarity, it is excluded from the array of values. Permutation occurs by complete search. Next, a centered series of values is formed based on the calculation of the average value of the maximum emissions of the side lobes of the CCF of signals. The signals generated by this method have a low level of cross-correlation due to the permutation of frequency elements by complete search from different output sequences in different frequency bands and changes in the width of the filter bands. Improved method of forming of complex signals ensembles obtained by permutation of time intervals of sequences based on a centered series, which differs from the known in formation of a centered series based on the average value of maximum emissions of side lobes of CCF, which reduces the level of multiple access interference and increase the ensemble volume. The signals generated by this method have a low level of MAI, which is determined by the values of the maximum emissions of the side lobes of the CCF. Studies of the intercorrelation properties of signals obtained by permutation of time intervals of sequences based on a centered series show that they satisfy the condition of minimum similarity and have better, in relation to known signals, intercorrelation properties. The formation method of complex signals ensembles, based on sequences with improved intercorrelation properties, which are obtained by bandpass filtering with permutations, implemented on the basis of selection from the spectrum of sequences of equal bands with subsequent transfer in the common frequency domain of the wireless high-speed data transmission standard and the subsequent application of permutations, which allows you to form ensembles of complex signals with the required levels of maximum emissions of the side lobes of CCF. The optimal value of the filter band is equal to 0.2 % of the total frequency band of the output sequences, while the correlation properties of the signals satisfy the condition of minimum similarity and such signals can be used in cognitive telecommunications systems. The comparative characteristic of intercorrelation properties of signals is studied, as a result of which it is revealed that the formed signal ensembles, by the method of permutation of time intervals of sequences on the basis of the centered series, have better intercorrelation properties than ensembles on the basis of known signals. The level of maximum emissions of the side lobes of the CCF of the developed signals is 7-12 % less than the known signals. The comparative characteristic of ensemble properties of signals, on the basis of sequences with the improved intercorrelation properties which are received by a bandpass filtering with permutations with known signals is studied. The obtained results show that the formed ensembles of signals have a larger volume (by 16-26 %) in comparison with ensembles based on known signals. Developed signals should be used with any number of subscribers. The filter band should be selected in the range from 0.1 to 2 % of the total width of the main lobe of the sequence spectrum for practical use in cognitive telecommunications systems.