STUDY OF MODIFIED ALGORITHMS WITH SIGNAL CONSTELLATION ROTATION IN DTMB STANDARD ON THE BASIS OF SIMULINK MODEL IN MATLAB ENVIRONMENT
S. N. Meleshkin, I. B. Siles · Известия Южного федерального университета. Технические науки · 2024
This paper discusses modified algorithms with signal constellation rotation applied in the digitalterrestrial television multimedia broadcasting standard adopted in Cuba. Compared to usingconstellations without rotation, these algorithms give a significant increase in system performance underchallenging reception conditions, with industrial interference and low signal-to-noise ratio. This paperanalyzes the effect of the angle and direction of rotation of the signal constellation on the stability of thedigital terrestrial television multimedia broadcasting system. The main purpose of this paper is to analyzethe effect of the angle and direction of rotation of the signal constellation on the stability of the digitalterrestrial television multimedia broadcasting system. For the study, a proprietary architecture of digitalterrestrial television multimedia broadcasting system adopted in Cuba was developed, implemented inSimulink in Matlab environment. This Simulink model allows analyzing the dependence of the bit errorrate on the value of white Gaussian noise for different system configurations. The model of additive whiteGaussian noise, which is mixed with the generated signal, is widely used in the research. The proposedmodifications allow the reception of digital terrestrial television multimedia broadcasting in fade-freechannels with equal values of the bit error rate for all cases analyzed. In this case, in order to obtain asignificant gain from constellation rotation, in the order of seven decibels, it is proposed to transmit thequadrature and in-phase components on different subcarriers and at different moments of time. In thescheme with signal constellation rotation, the quadrature component should be transmitted not on thesame subcarrier, but with a delay and on a different subcarrier. Then from one quadrature amplitudemodulation is actually two amplitude binary modulation in-phase and quadrature projection, which aretransmitted on independent subcarriers, and affected by interference differently, which provides reliabledemodulation at lower values of the signal-to-noise ratio and the impact of industrial noise. A disadvantageof the algorithm is that it does not sufficiently counteract Gaussian noise.