CHARACTERISTICS IMPROVEMENT OF THE WIDEBAND TELECOMMUNICATION SYSTEM APPLYING CHAOS BASED PSEUDORANDOM SEQUENCE
Keywords:telecommunication system, broadband pseudo-noise signal, logistic mapping, signal base, radio channel.
Background. Telecommunication systems with a broadband signal have undoubted advantages: increased noise immunity with narrowband and wideband interference, confidentiality of information transmission, as well as improved electromagnetic compatibility with neighboring radio-electronic devices. A broadband signal is usually formed by direct spread spectrum using well-known classical pseudo-random sequences (PRS): m-sequences, Kasami, Gold, Walsh sequences, which can be decoded and received at the receiver.
Objective. The aim of the paper is creating PRS on the basis of chaos, which the subscriber is practically unable to decode, and thus ensure increased confidentiality of information transmission.
Methods. Using the mathematical model of chaotic logistic mapping, which, as shown by preliminary studies, provides the best results, as well as referring to the bifurcation diagram of Feigenbaum, the parameters of 3-secret keys
are defined and the PRS of the selected length is created. Based on the application of the graphical user interface developed in the MATLAB system, a correlation analysis of the resulting PRS is performed and the PRS is determined
with the minimum side lobes of the autocorrelation function.
Results. By empirical decision of 3 secret keys of the dynamic parameter of the Feigenbaum diagram, the initial value of the sequence and the number of the initial pulse of the PRS, as well as the study of the autocorrelation function,
we obtained a PRS with a side lobe level of the autocorrelation function acceptable for practical use of no more than 0.25.
Conclusions. The use of well-known pseudo-random sequence: Walsh’s, Kasami’s, Gold’s, creating a system with a noise-like signal doesn’t ensure complete confidentiality of information transmission, since they can be decoded.
The most acceptable by the criterion of the side lobe minimum of the autocorrelation function – no worse than 0.25 – is the use of chaos based on the Feigenbaum logistic map. When creating pseudo-random sequences based on chaos, the best results are obtained by choosing the maximum value of the dynamic parameter of the Feigenbaum diagram at the level of the boundary value equal to 4, with an accuracy of 0.05.
Varakin L.E. Communication systems with noise like signals. M.: Radio and communication, 1985. - 384 p. (In Russian)
Sklar B. Digital communications. Fundamentals and Applications. Edition.2,: Translation from English. – M.: Publishing House Ltd «Williams», 2004. – 1104 p. (In Russian)
Yu.M. Boiko and R.O. Boryachok. “Improving effectiveness for processing signals in data transmission channels with рhase manipulation”, in 2013 23rd International Crimean Conference Microwave and Telecommunication Technology (CriMiCo), CriMiCo, 2013, pp. 262-263.
Oleg Shynkaruk, Juliy Boiko and Oleksander Eromenko. “Measurements of the energy gin in the modified circuit signal processing unit”, in 2016 13th International Conference on Modern Problems of Radio Engineering. Telecommunications and Computer Science (TCSET), 2016, pp. 582-584.
Ipatov V.P. Broadband systems and code channels division of the signals. M.: Technospera.2007.488 p. (In Russian)
Bobalo, U.Y. Practical use of the chaos systems theory in telecommunications: monograph/ U. Y. Bobalo, S. D. Galiuk, М. М. Klimash, R.L. Politanskiy. – Drogobuch – Lviv: Kolo, 2015. – 184 p. (In Ukrainian)
Anatolii Semenko Creation of pseudo-random sequences based on chaos for forming of wideband signal /Anatolii Semenko, Nikolai Kushnir, Nataliya Bokla, Grigoriy Kosovan// Information and Telecommunication Sciences, 2017, Volume 9, Number 2, pp 5-10.
Semenko A.. Kushnir N. Bokla N. Kosovan G. Features of creating based on chaos pseudo-random sequences. Мodern Problems of Radio Enginiring,Telecommunications, and Computer Sciens. Proceedings of the XIIth International Conference TCSET’ 2018. Lviv Slavsco,Ukraine.February 20-24 , 2018.Pp338-342.
Bokla N.І. Research of the PRS correlation properties based on gold code using Mathlab by //Vistnuk DUIKT.-2011.-Vol.9. - №4.-pp.386-391