Baliar V. Influence of impairments in digital television broadcasting paths on their functioning technical quality

An object is functioning process of digital terrestrial TV broadcasting path in DVB-T/DVB-T2 standards during individual and combined impact of various impairment types. An objective is to define relationship between technical quality of digital TV broadcasting paths and levels of single and combined impairments at levels of RF signal, transport and video streams with the development of proposals for technical norms for the parameters to be monitored. Research methods: methods of mathematical statistics, mathematical modeling, system analysis, mathematical interpretation of experimental data, estimation methods of digital system path impairments and objective assessment of image quality. Theoretical and practical results: classification of methods for monitoring the technical quality of the digital TV broadcasting system based on a multi-level approach is provided. Estimation is given to technical quality degradation of the DVB-T / DVB-T2 systems at condition of impact of simultaneous and combined radio frequency distortion of different types. Technical norms for impairmnet and technical solutions to minimize the negative impact of RF distortion without complexity icreasing of digital TV receiver are developed. Estimation is given to technical quality of the digital TV broadcasting service on transport sream level for different approaches to the monitoring with establishment of the relationship between temporal indicators and subjective assessment of the quality of the path. Classification of impairments on MPEG video stream level during transmission via digital TV broadcasting paths are builded. The estimation is given for structural and other impairments at different video sequences encoding parameters in the broadcast channel with usage the proposed set of parameters characterizing the degree of MPEG video impairments in spatial and temporal domains. Technical implemention solution for monitoring system of digital TV broadcasting path at level of video streams are developed, based on the use of objective metrics for evaluating the quality and structural impairment metrics. Scientific novelty: Classification of digital TV broadcasting path operation technical quality control methods with the use of multilevel approach is first proposed. The quantitative and qualitative estimations of separate and combined influence of Additive White Gaussian Noise (AWGN) and quadrature impairments and also AWGN and phase noise on technical quality of DVB-T/DVB-T2 systems path operation are firstly obtained and propositions on technical norms on permissible levels of impairments are formulated. The quantitative estimations of impairments in a transport stream and corresponding failures in service operation of digital TV broadcasting are firstly given and relationship between the indexes of operational quality and subjective quality of the decoded video sequence is established. Classification is firstly built and influence of RF impairments of audiovisual service signals arising during distribution of the broadcasting programs on quality of image decoding in a receiver at different configurations of video encoding subsystem is estimated and propositions on parameters, that must be used during control of such impairments and corresponding criteria are developed. Appliance of objective quality estimation metrics for technical quality control in digital TV broadcasting with the aim of increase of efficiency of the monitoring system in terms of operability and reducing of complexity of digital image cliff effect detection is estimated. The results of studies are implemented in such organizations: the Odessa National Academy of Telecommunications n.a. A.S. Popov, State Enterprise “ the Ukrainian Scientific Research Institute of Radio and Television ”, offered for the use in the educational process of the Academy and in international standardization.