A.K. Gaysin - Assistant, Department of «Radioelectronics and Telecommunications systems», Kazan National Research Technical University named after A.N. Tupolev (KNRTU-KAI). E-mail: akgaysin@kai.ru A.F. Nadeev - Dr.Sc. (Phys.-Math.), Professor, Director, Institute of Radioelectronics and Telecommunications, Kazan National Research Technical University named after A.N. Tupolev (KNRTU-KAI). E-mail: afnadeev@kai.ru