DVB-C2 for Delivering 3DTV
Justo Rodal Pérez, Director of R+D, Televes
DVB member Televes, a global firm specialising in the distribution of TV signals throughout building infrastructures, is set to deploy the first project in Spain for delivering 3DTV services over DVB-C2. Televes leads the DERFO 3DTV project, supported by several universities, the Gradiant Technological Center and Continental Networks. The DERFO 3DTV project is an ambitious endeavour to distribute 3DTV over fibre optic and coaxial networks using the latest cable transmission scheme DVB-C2. DVB-C2 was selected for its high bandwidth efficiency, which is necessary to deliver 3DTV services.
The DERFO 3DTV project aims to implement the suitable infrastructure to distribute the latest multimedia and interactive applications. It is utilizing fibre optics as the paradigm of the high-capacity/high-efficiency network while also taking into account the massively deployed coaxial infrastructures. In addition the project explores the possibility of using wavelength multiplexing technologies to enlarge the capacity of distribution networks.
The results of the project can be used by cable operators as well as by small and medium so-called coaxial telecommunications common infrastructure platforms (ICT). The new ICT regulation, which has recently been approved in Spain, covers both fibre optic and coaxial cable for broadband access and therefore the regulators look to ease the introduction of “Digital Home” services in households and buildings.
The ICT, as it is defined in Spain, regulates the level and quality of the signals deployed, covering today’s analogue signals, first generation DVB signals and the second generation satellite DVB-S2. This ICT legislation is an evolution of the Spanish Law 49/1966, which declared by obligation that a communal antenna should be installed on any newly constructed building. It also gives guidelines to ensure the quality of the reception. This is achieved through a detailed study of technical features designed to prevent internal and external interference and to ensure, that in similar conditions, the reception through a communal antenna system must surpass the quality of reception that would be provided through individual antennas. It is the combination of three pillars – quality, efficiency and multiservice sharing that best defines the goals of the DERFO 3DTV project.
The rapid increase of HDTV and 3DTV services, which is foreseen over the next few years, will bring the current distribution networks to their limits. In addition, terrestrial and satellite analogue switch-offs paradoxically will not put an end to analogue signals, but they will continue to play a significant role in service distribution in the years to come. DVB-C is still being rolled out, as it is a stable technology with millions of STBs deployed all over the world to distribute broadband and HDTV. Therefore, there is not sufficient capacity for new services! The bandwidth scarcity is mitigated in part by extending the distribution bandwidth up to 1 GHz, which is a requirement of several cable operators in Europe and America. While this solution can be implemented in cable networks, for ICT networks, where satellite is being delivered in IF, the only solution is to use the available bandwidth more efficiently. Therefore, DVB-C2 is the best solution for providing the required capacity; not to mention its flexibility to adapt to different service requirements in these networks. With its wide range of supported modulation and Forward Error Correction (FEC) modes DVB-C2 can be adapted to all relevant network characteristics.