Research of methods and means of signal modulation with high interference resistance in modern mobile networks

Abstract

Systems of multiposition signals are investigated, on the basis of which it is possible to reach the transmission speeds close to the bandwidth of communication channels. In communications systems, where the most stringent requirements for noise immunity are the most effective, it is most efficient to use multi-position signals with phase-difference modulation, for which the equivalent energy is maximal. The optimal incoherent reception has the status of optimal for signal variants with an unknown and uniformly distributed initial phase. Optimal incoherent reception is understood as a non-coherent processing method that ensures the minimum probability of error when receiving signal elements in a channel with Gaussian white noise with a random and uniformly distributed initial phase of the received element (about which nothing else is known). All other non-informative parameters of the signal, except for the initial phase, primarily - the frequency and processing interval, with optimal non-coherent reception, must be known precisely. As for the signal amplitude, when using signals with equal energy, it may be unknown. With regard to FM signals, the optimal incoherent method of reception can be used only to determine the phase of the transmitted difference (and not the absolute phase), which is fundamentally unknown with this processing method. The main method of synthesis of algorithms for optimal incoherent reception of signals from FRM-1 is considered, which considers all possible situations when processing signals on two parcels. An algorithm for optimal incoherent reception of signals from FDM-1 is developed, suitable for implementation with any set of information phase differences. The algorithm of optimal incoherent reception of signals from FDM-2 is developed. It is concluded that the optimal incoherent reception of signals from the FDM allows, by increasing the processing interval, to approach the potential impedance of the given signal system without evaluating the initial phase.