EMC-Influences on Digital Broadcasting Services in Vehicular Environments

From home entertainment we know a number of digital entertainment sources which we cherish. Especially digital broadcasting, such as DAB, DVB, HD-Radio and SDARS just to name a few, are entering the automotive market. Premium car manufacturers are offering DAB, DVB-T as well as HD-Radio and SDARS as digital sound broadcasting for their customers. However, a lot of efforts need to be undertaken to get good performance. This paper deals with answering the often asked question, why digital broadcasting systems in vehicular environments do not perform as good as their theoretical performance should intend. With an excessive measurement campaign with a number of premium car manufacturers in Germany, we found three main arguments; a) the digital modulation becomes week in terms of bit-errors with enhanced data rates b) wideband modulation schemes, such as COFDM for example, are fragile in fading environments, especially reactive on frequency selective fading and c) used coding and modulation techniques can cope with single-frequency and single-event interferences well but not with permanent broadband interference, which are often found in EMC signatures in well-equipped luxury cars.