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).