Анализ помехоустойчивости квадратурных методов модуляции при повороте сигнальных созвездий

Abstract

The paper considers the effect of the rotation of the signal constellation on the noise immunity of quadrature multi-point modulation methods. Based on the error vector in the Matlab+Simulink simulation environment, models of M-QAM modulators and demodulators with rotation of the signal constellations at an arbitrary angle are proposed. Considered the most commonly used in digital data transmission systems modulation: 4-QAM, 16-QAM, 64-QAM and 256-QAM. The simulation results of the proposed models confirmed the coincidence of the values of the rotation angles of the signal constellations recommended by the DVB-T2 standard, and also revealed the values of other angles that can be used to improve the noise immunity of multipositional quadrature modulation methods.