Numerical and empirical investigations of the effect of propagation channel on modulation error ratio in UHF broadcasting systems

This paper presents a combined numerical and empirical investigation of how propagation channel conditions shape Modulation Error Ratio (MER) in UHF DVB-T broadcasting. A MATLAB/Simulink DVB-T physical-layer model is extended to quantify the MER–CNR divergence under Rician fading with varying K-factor and under Doppler-induced time variation. To validate the analysis, an extensive field campaign is conducted in a metropolitan DVB-T network using three transmitters and 534 measurement samples. Measurements are further classified into line-of-sight (LoS), obstructed line-of-sight (OLoS), and non-line-of-sight (NLoS) scenarios using terrain profiling, enabling a physically grounded interpretation of MER variability. Results show that the MER–CNR deviation can reach approximately 7.5–12 dB depending on obstruction severity and fading conditions, confirming that CNR alone may not capture modulation quality in realistic environments. Finally, a nonlinear regression model is developed to predict MER from received power, CNR, and their interaction, achieving R2=0.83 and RMSE =2.29 dB. The proposed framework provides both explanation and a practical tool for MER-aware planning and quality monitoring of UHF broadcasting systems.