Khakhliuk O. Development of method for optimal reception of the multi-position signals in modern mobile networks.

The thesis is devoted to the development and research of methods for optimizing a multi-position signal for reliable digital information transfer using OFDM systems and LTE technology in order to create highly efficient mobile networks, as well as solving scientific and technical problems and developing algorithms for optimizing multi-position signals with amplitude-phase modulation in OFDM systems. It was defined that the use of OFDM systems ensures invariance property as to random perturbations. Investigated: modulation techniques that affect the speed and reliability of digital transmission; systems of multi-position signals, on the basis of which it is possible to achieve data transfer rates close to the capacity of communication channels. It was conducted analysis of situations with conditions corresponding to the optimal incoherent and autocorrelation processing methods for receiving multi-position signals, the noise immunity of demodulators that implement these reception methods is determined. Universal algorithm was proposed which provides for optimal coherent reception of multi-position APSK (amplitude phase shift keying) and DAPSK (differential amplitude phase shift keying) signals in OFDM systems. Specific algorithms were developed for coherent processing of efficient multi-position signal systems. Suggestions were made for choosing of the optimal multi-position signal for a communication channel with a certain signal-to-noise ratio. The algorithm was developed for optimal reception of multi-position signals against the background of interference based on rank methods under conditions of a priori uncertainty. The obtained results ensure data transmission with a predefined probability in OFDM systems while effectively improve the quality indicators of communication channels and therefore are expedient for implementation.