Assessment of digital television signal processing for correction of interference distortions in single-frequency DVB networks

This research studies in which way the interference that occurs in Single-Frequency Networks for Digital Television broadcasting affects the reception quality in the overlapping service zones of transmitters. The article contains qualitative and quantitative evaluation of the effectiveness of the interference distortion compensation in the receiver’s demodulator. The results were obtained using CADs VSS Applied Wave Research and ADS Agilent Technologies and allow us to evaluate a limiting value of the signal-to-echo-signal ratio for a given signal-to-noise ratio that provides the network operability. The DVB network operability in the presence of transmitter clocking depends on the stability margin, which is defined by the permissible value of a bit error rate (BER) within a threshold. From the obtained results it follows that the interference-impact threshold corresponds to the BER equal to 2 × 10-4. For below-threshold BER values, the reception becomes almost error-free due to the use of a Reed-Solomon decoder. Codec replacement in the second-generation DVB networks resulted in a significantly decreased BER threshold value to 10-2 - 10-3, which allowed the data transfer rate to be increased while keeping the stability margin in terms of the bit error rate. The developed method for studying the performance of digital broadcasting networks and systems allows causes behind the increase of BER to be identified in practice based on spectra and signal constellations diagrams, also enabling the comparison of various algorithms for the assessment of data channel performance and digital television signal processing in terms of the effective suppression of interference distortions.