DTT NETWORK STRUCTURES AND TECHNICAL INNOVATIONS
A. Morello, G. Alberico, P. Forni, V. Mignone, S. Ripamonti, B. Sacco, V. Sardella, M. Visintin, 

Rai - Centro Ricerche e Innovazione Tecnologica - Turin - Italy

The RAI Research Centre (RAI-CRIT), in co-operation with RaiWay, is analysing the architecture of the primary distribution and broadcasting network for DTT (Digital Terrestrial Television) introduction in Italy. The article describes the overall digital platform for encoding, multiplexing and emission of two independent DTT bouquets. The primary distribution network structure is analysed, suitable to differentiate the programme content over the 20 Italian Regions. The network will be capable of evolving progressively from a low-cost solution, based on DTH satellites feeding the terrestrial transmitters, to a final configuration, using optical fibres and radio links as main backbone and satellite links as a backup. A new MUX-adapter concept is introduced, allowing to drop some TV programmes from the DTH satellite bouquet, while significantly reducing re-multiplexing cost. Examples of broadcasting network coverage estimation are presented, according to the studies developed by the Authority on Communications. An enhanced in-band gap-filler scheme is proposed, using adaptive echo cancellation to maintain stability and high performance at increased ERP levels.