Utilization of scrambling coding sequences based on primitive polynomials in telecommunication networks of information systems

DOI: 10.31673/2412-9070.2020.024754

Abstract

Properties of different scrambling coding sequences are considered with the aim to enhance noise immunity and concealment characteristics of information transmission. It is proposed to use coding sequences based on primitive polynomials, which are known to possess very good autocorrelation properties. Those polynomials can be deduced through polynomial division or found in a reference table. An eighth degree polynomial is selected and the corresponding scrambling coding sequence is synthesized. This coding sequence includes 255 chips and can increase the occupied spectrum by eight times. It is shown that the autocorrelation properties of the sequence degrade when a bit sequence has bits with different signs in binary phase modulation. By employing computer simulation, autocorrelational properties of the coding sequence are studied, as well as its performance in information transmission on the background of the internal noise and external interference. Computer simulation was carried out for a number of desired signal values. Those values were selected to study behavior of the scrambling coding sequence in difficult interference situations; the total noise and interfering signal to desired signal ratio assumed values of 6, 9 and 12 dB. It is proven that synthesized coding sequence permits to substantially improve information transmission quality indicators; even if the above ratio equals 12 dB, the desired signal can be extracted from the mixture of the internal noise and interfering signal and the transmitted bit sequence can be identified. Designed coding sequence is proposed to be used for bit sequences scrambling in practical implementations of telecommunication channels. Further research is aimed to study properties of the coding sequences based on the primitive polynomials of the order higher than eight.

Keywords: telecommunication networks; primitive polynomials; scrambling coding sequences; channel quality indicators; computer simulation; information systems.

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