Optimization of DVB-T Networks for the Provision of Local and Mobile Services

Nowadays, the main standard around the world for digital terrestrial TV broadcasting is Digital Video Broadcast - Terrestrial (DVB-T). Most of DVB-T networks deployments have been designed for fixed rooftop antennas and high transmission capacity, without providing good coverage level for vehicular mobile reception. These networks also make use of either a Single Frequency Network (SFN) or a Multi Frequency Network (MFN), but none of these topologies is ideally suited for delivery of both global and local services in an efficiently way. This article discusses the use of the hierarchical modulation, the Scalable Video Coding (SVC), antenna diversity reception, Application Layer Forward Error Correction (AL-FEC) and time slicing techniques for the optimization of DVB-T networks in two different issues: the provision of mobile digital television in vehicles and the transmission of local services in SFN topologies. The paper shows that the combined usage of these solutions can compensate the impairments caused by the mobility of the receivers, such as signal fast fading due to Doppler shift, and the poor coverage at ground level. Furthermore, our results show that it is possible to enable Local Services Areas (LSAs) in SFNs without affecting the availability of neither global services nor any of its all advantages. Performance evaluation results have been obtained through field measurement campaigns, laboratory testing and dynamic simulations in the city of Valencia (Spain).