This week the DVB Steering Board approved the Alcatel specification for mobile TV from satellites now officially dubbed as DVB-SH (satellite services to handhelds).
Two documents specifying DVB-SH were approved: a waveform specification and a description of the system. The specification was developed by the DVB Technical Module’s TM-SSP working group.
But all the heavy lifting was carried out by Alcatel, which has worked hard to convince the DVB Project to put its name to a system that is very similar to DVB-H except that it works in different spectrum ‘ 2.2 GHz is available as S-Band and the system will work up to 3 GHz – and its gap filler strategy is in line with cellular networks so that no new physical sites are required for implementation.
DVB-SH uses the same OFDM physical layer with time interleaving and frequency interleaving and forward error correction built into the DVB IP Datacast content delivery structure. It will also use the same electronic service guide and DRM standards.
The DVB Project said that DVB-SH specifies two modes, one where the ground based gap fillers work in the same frequency as the satellite and reinforce the signal, called SH-A and the other (which is How Alcatel says its expects it to be used) which offers a different signal from each source, called SH-B, which uses a Time Division Multiplex (TDM) on satellite with COFDM on the terrestrial link. DVB will now issue guidelines for implementation of the standard.
Our own view is that there are merits to this approach and that Alcatel will get France, and at least one other European country to adopt either DVB-SH on its own, or in conjunction with DVB-H in urban areas. For instance in the UK where there is no real spectrum available for DVB-H, this might be an ideal system for high quality mobile TV, and in Central Europe, it might be a cheap way into mobile TV.