Scientific and Engineering Proposals for Improving the Noise Immunity of Receiving Multi-Position Signals in Channels with Variable Parameters

Introduction. An important task faced by the developers of modern telecommunication systems consists in increasing the noise immunity of signal reception in channels with variable parameters. Thus, the communication lines of DVB-T2, DVB-S, and DVB-S2/S2 standards widely apply signal structures (SS) of multi-position quadrature amplitude modulation (M-QAM). However, an analysis of scientific publications shows that the random nature of the phase change of the transformed signal constellation leads to a loss of noise immunity of the M-QAM signals. Engineering solutions for the effective reception of such signals are lacking. The proposed block diagram of a device for receiving quadrature amplitude signals and the developed operation algorithm for an amplitude-phase detector allow random phase changes to be considered and reduced. Aim. Development of scientific and engineering proposals to improve the efficiency of receiving M-QAM signals in radio channels with random phase changes. Materials and methods. The study was conducted using the methods of noise immunity research, as well as communication theory and signal theory. Results. A block diagram of a device for receiving quadrature amplitude signals and an operation algorithm for an amplitude-phase detector were proposed, which allow random phase changes to be considered and compensated for. Scientific and engineering proposals were formulated to improve the noise immunity of M-QAM reception in channels with variable parameters. Conclusion. The developed scientific and engineering proposals for increasing the noise immunity of multi-position quadrature signals in channels with variable parameters substantiate both the feasibility of using a transformed SS M-QAM with improved energy characteristics, as well as the application of the developed receiving device for processing quadrature amplitude signals and the operation algorithm of an amplitude-phase detector. The results obtained make it possible to perform demodulation with simultaneous compensation of phase distortions to increase the noise immunity of M-QAM signal reception.