Pliushch O. Models and methods of information processing in mobile networks based on multi-positional wideband signals

The thesis is devoted to development of models and methods of information processing in mobile networks based on multi-positional wideband signals and to design of the conception that relies on new principles to improve efficiency of such networks, which secures simultaneously their high noise immunity, concealment of information transmission and robustness to the signal propagation environment. The paper has contributed to the theory and practice of use of adaptive antenna array and pseudo-noise coding sequences derived from primitive polynomials in mobile networks of telecommunication systems. An analysis of signal propagation performance in mobile radio channel is carried out and different methods of information protection from interception and eavesdropping in telecommunication channels are considered. Performed analysis of the methods of countering fast fading and information protection proved that a complex solution of these problems is possible under combined use of adaptive antenna arrays and wideband signals with direct spectrum spreading. A method of adaptive antenna array adjustment is synthesized that does not require formation of the reference signal, which was tested with use of automatic gain control and hard limiters. With account of adaptive array initial weight vector position with respect to eigenvectors of its correlation matrix, existing adaptation methods for such systems are improved. A universal integral indicator for adaptation performance assessment of adaptive arrays without carrying out respective computer simulation is synthesized. Properties of pseudo-noise coding sequences are evaluated with respect to their abilities to secure required noise immunity and information transfer concealment in mobile networks. A method of the telecommunication channel creation is designed in which researched pseudo-noise coding sequences are used in combination. Utilization of hard limiters to match receiver dynamic range and that of the signal mixture is researched. Dynamics of mobile communication generations is considered and some problems are revealed with both existence of a certain conception of mobile communication systems design and with its perfection and implementation correctness. With account of the necessity formed due to the above, a conception of mobile communication network design is created that eliminates the deficiencies present in the development of existing networks. Such a conception permits to create highly-efficient mobile communication networks with use of new principles, for example synergy. With utilization of the designed conception and its underlying principles, a method of signal processing in mobile networks with multi-positional wideband signals is obtained. With implementation of synergy principle, this method permits in a special mobile communication network to simultaneously secure information transfer concealment, its protection from interception and robustness to multipath propagation. Thus, in comparison with the existing approaches, models and methods of information processing in mobile networks with multi-positional wideband signals proposed in this paper permit to substantially increase efficiency of such networks according to the purpose of the research.