Abstract
Functioning of a number of modern infocommunication systems (ICS) is carried out under external and internal influences, caused, on the one hand, by natural interference, interference from other radio systems operating at close frequencies or in a common part of the frequency range, on the other hand, intentional interference created by counteraction stations with the aim of electronic suppression of existing systems. Possible strategies of the counter station are as follows: determining the content of messages when legal subscribers use cryptographic data protection algorithms; falsification of messages; violation of data integrity; staging of various types of interference, etc. Therefore, more stringent requirements are imposed on the ICS, especially for critical purposes, to ensure the effectiveness of their functioning: reliability and speed of information transfer, survivability, noise immunity, information security. In such conditions, the presence and use of protected ICS is of particular importance. Under the security systems one should understand, first of all, their ability to provide the necessary indicators for noise immunity, information, energy and structural secrecy, information transfer speed, frequency and energy efficiency. The need for the use of secure systems makes researchers take a fresh look at both the modes of operation of secure radio channels and the aspects of formation and use of complex signals – physical data carriers for such systems. In this paper, based on the study of the algebraic structure of systems of non-linear parametric irregularities, the problems of synthesis of a number of classes of quasi-optimal uniform, non-uniform, complex discrete signals with specified correlation, ensemble and structural properties, including such signal systems that have the properties “blur" by correlation properties. This property means that an increase or decrease in the duration of a discrete sequence does not change the correlation properties of the signal, on the basis of which the signal is synthesized. It is shown that the use of many of the indicated signal systems in modern information and communication systems will improve such indicators of the functioning of such systems as noise immunity, operational secrecy, information security, noise immunity of signal reception.
Highlights
IntroductionIn modern telecommunication systems and networks the task of providing the necessary indicators of noise immunity (noise immunity and secrecy functioning) at the level of the source of signals – physical carriers of information is traditionally solved on the basis of increasing the ratio of signal power to the power of interference at the reception of the receiving device, as well as improving the directivity of the antennas of the transmitter and receiver
In modern telecommunication systems and networks the task of providing the necessary indicators of noise immunity at the level of the source of signals – physical carriers of information is traditionally solved on the basis of increasing the ratio of signal power to the power of interference at the reception of the receiving device, as well as improving the directivity of the antennas of the transmitter and receiver
Under the problem of signal synthesis we will understand the task of constructing dictionaries of vectors (Wmq ), q 1, N, m 1, M, the whole set of which forms a system of uniform quasi-orthogonal signals (UQOS) of Mk N M x dimension such that the following conditions are fulfilled in each of the dictionaries
Summary
In modern telecommunication systems and networks the task of providing the necessary indicators of noise immunity (noise immunity and secrecy functioning) at the level of the source of signals – physical carriers of information is traditionally solved on the basis of increasing the ratio of signal power to the power of interference at the reception of the receiving device, as well as improving the directivity of the antennas of the transmitter and receiver. One of the ways to solve this problem is to use radio channels with frequency redundancy [1 – 4] To provide this type of redundancy, discrete signals are widely used at the physical level, in which manipulated parameters (amplitude, phase, frequency) are changed at strictly fixed time intervals. In the systems of radar, sonar, navigation, communication and transmission of information the use of the discrete sequences for the formation of complex wideband and ultrawideband signals as manipulating sequences made it possible to resolve the contradiction between the throughput and range of the systems operation, to increase their noise immunity and electromagnetic compatibility, increase radio bandwidth efficiency use due to code division of channels, to improve the ecology in the radio coverage area by reducing the peak radiation power, create satellite-based radar, radio navigation and communication systems, providing for observation, determination of coordinates and transmission of information to any point on our planet, to implement hidden location and communication using noise-like signals and much more. All of them differ from each other by the rule and the coding power, the priority qualitative characteristic (sequences with perfect periodic autocorrelation function, orthogonal, quasi-orthogonal, trans-orthogonal, maximally trans-orthogonal, optimum in minimum-maximal, or in some other kind, noise-like sequences, periodic, impulse, regular, irregular impulse sequences, etc.); they differ in a number of essential parameters (characteristics): period (length), peak factor, degree of equilibrium, uncertainty function, autocorrelation, reciprocal and butt-correlation functions, etc
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