On Transmitting of Global and Local Contents within DVB-T Single Frequency Networks

Current broadcast digital networks make use of either a Single Frequency Network (SFN) or a Multi Frequency Network (MFN). None of these networks topologies is ideally suited for delivery of both global and local services in an efficiently way. MFNs enable the transmission of local services but need a significant amount of frequencies and therefore large amounts of valuable spectrum. SFNs are especially suitable for global services due to mutual support of the signals from multiples transmitters operated in the same frequency. SFNs are very spectrum efficiently; however they do not support local services. In this paper a hierarchical modulation method and Time Slicing technology are proposed for providing local and global contents in a terrestrial SFN (such DVB-T) keeping all its advantages. The hierarchical modulation has already been included in the DVB-T standard and time slicing solution is backwards compatible, in the sense that receivers that have been deployed in the original system can continue receiving data without hardware modifications. The performances of these technical solutions for both global and local services are analyzed. The applicability of these concepts is shown by a signal propagation simulation and coverage estimation in real scenario of Valencia region (Spain). © 2005 IEEE.López Sánchez, J.; Romero Ruescas, C.; Gómez Barquero, D.; Cardona Marcet, N. (2011). On Transmitting of Global and Local Contents within DVB-T Single Frequency Networks. IEEE Latin America Transactions. 9(5):444-453. doi:10.1109/TLA.2011.6030975S4444539

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

[EN] 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).This work has been partiality supported by the Spanish Ministry of Industry, Tourism and Trade under project Redes Hibridas TSI-020307-2010-165 and the FEDER founds.López Sánchez, J.; Romero Ruescas, C.; Gómez Barquero, D.; Cardona Marcet, N. (2011). Optimization of DVB-T Networks for the Provision of Local and Mobile Services. Waves. 3:48-57. http://hdl.handle.net/10251/56301S4857

Herramienta de simulación de redes de sensores móviles en un entorno urbano y su aplicación al Sensor Web

[ES] Desarrollo e implementación de una herramienta de simulación de sensores móviles[EN] Development and implementation of a simulation tool of mobile sensorsRomero Ruescas, C. (2012). Herramienta de simulación de redes de sensores móviles en un entorno urbano y su aplicación al Sensor Web. http://hdl.handle.net/10251/30820.Archivo delegad