Tag Archives: DVB-T2

Danish T2-Lite trial goes for all-mobile channel offer

Details have emerged about some of the technology choices adopted for the Copenhagen ‘T2-Lite’ trial, for which Danish operator Open Channel was awarded a licence in August last year.

The trial, which launched on January 1st this year and could run for up to three years, uses UHF channel 39 in Copenhagen, and claims coverage of more than 700,000 households.

In contrast to the BBC R&D trial last year, which squeezed a T2-Lite channel designed for mobile reception into the gaps between a fully-fledged HD service transmitted in standard DVB-T2 mode (now dubbed ‘T2-base’), the Copenhagen trial consists entirely of T2-Lite TV and radio channels carried on up to 16 Physical Layer Pipes (PLPs). As their name suggests, each of these can be regarded as a separate data-pipe with its own bit-rate and robustness characteristics, a notable feature of the second-generation DVB DTT standard.

Open Channel’s calculations show that configured in this manner, a T2-Lite multiplex can match the data-rate offered by a DVB-T one (see table below), yet still offer good mobile reception (unlike DVB-T as generally configured).

Stationary reception DVB-T 20 – 22 Mbit/s DVB-T2 37 – 40 Mbit/s
Mobile reception DVB-H 10 – 13 Mbit/s DVB-T2 Lite 20 – 25 Mbit/s

Source: Open Channel

The difference between the T2-base multiplex data-rate (40.2 Mbit/s in the UK) and that of a T2-Lite mux (20-25 Mbit/s) is explained by the fact that the PLPs within it are configured to be much more robust for mobile reception purposes, so run at lower bit-rates (the DVB-T2 spec sets a maximum of 4MBit/s for PLPs when T2-Lite is used).

But that in turn means that they can easily be captured by fixed aerials, too: in other words, the same channel offer is receivable on either living-room displays fed from a fixed rooftop antenna or handheld devices equipped with a T2-Lite tuner (the DVB predicted last September that soon, all [DVB-] T2 chipsets will support T2 Lite).

These channels will, of course, not be HD quality, but that has to be set against the fact that no separate (expensive) mobile TV network needs to be constructed.

One of the interesting assertions made by Open Channel is that DVB-T2 Lite is not only suitable for mobile TV. It is, the company says, “also highly suitable as the future standard of digital radio in place of DAB & DAB+ [...]. With the DVB-T2 / T2 Lite profile you get 2.7 to 3.7Mbit/s capacity (~ 40 / ~ 55 HE AACv2 radio stations) compared to the DAB / DAB+ 1.1 Mbit/s capacity (~ 6 mpeg1 layer II / ~ 16 HE AACv2 radio stations) with the same propagation model.”

Row over French DTT platform’s transition to DVB-T2

A row has broken out in France over the pace at which its DTT platform should migrate to DVB-T2 – the second-generation version of the DVB-T transmission standard.

Earlier this week, Catherine Morin-Desailly, the French senator who heads up the Senate’s media and new technologies working group, put out a press release questioning the imposition of the more efficient standard on new DTT channels. “Migrating to DVB-T2 is premature,” she said. “There’s no reason to make French consumers change their equipment again just to access a few extra channels.”

The channels in question are the so-called ‘bonus’ channels due to be awarded to incumbent terrestrial broadcasters on December 1st this year, the day after analogue terrestrial television is finally switched off in France. The European Commission (EC) has suggested the awards contravene European legislation.

Last month, the French newspaper La Tribune leaked the contents of a confidential notification by the French government to the EC of a projected change in French legislation aimed at imposing DVB-T2 on new terrestrial channels. The newspaper interpreted the move as a ruse designed to delay the launch of the controversial bonus channels, since no DVB-T2 receivers would be available to receive them.

‘T2-Lite’: a new candidate for mobile broadcasting

European digital TV standards body DVB has introduced a new, slimmed-down profile as part of the latest version of its next-generation DVB-T2 standard, targeting ‘low-capacity’ applications such as mobile broadcasting.
Known as ‘T2-Lite’, the new profile avoids processing- and memory-heavy modes, allowing more efficient receiver designs to be used – e.g. for a DVB-T2 tuner in a smartphone or tablet.
T2-Lite is limited to a maximum bit-rate of 4MBit/s, whereas the full HD-centric profile can run up to 48MBit/s (in the UK, DVB-T2 uses around 40MBit/s for DTT HD – see here.)
DVB says that “One possible use for T2-Lite enables the simulcasting of two different versions of the same service, with different bit-rates and levels of protection, which would allow better reception in fringe areas.”
According to a post on the BBC’s R&D blog, the BBC has been testing T2-Lite since July 7. In the trial, an HD signal for fixed reception and a T2-Lite version are combined within a single multiplex, with the T2-Lite frames placed in the gaps between the HD ones.
The concept that a single DVB signal could contain different versions of a broadcast which could be extracted by different receivers with different capabilities was proposed by the ‘god-father’ of DVB, Prof Ulrich Reimers, when DVB was originally set up, but has yet to prove popular in practice.
The BBC solution will be demonstrated at the forthcoming IBC exhibition in Amsterdam.

IBC Report – DVB-T2: a possible home for the DVB’s next-generation handheld standard?

Connected TV met up at IBC for the first time with Peter Siebert, who recently took over from Peter MacAvock as executive director of the DVB Project office (earning himself the nickname ‘Peter 2.0′ in the process), and was treated to the latest version of the DVB standards road-map.

One of the most interesting elements to come out of our discussion concerned the fate of what used to be known as DVB-H2 – the next-generation version of the mobile/handheld broadcast standard DVB-H.

Temporarily shelved because of an intervening effort to get the satellite/terrestrial hybrid version of DVB-H (DVB-SH) underway (its first European implementation will be on the Solaris Mobile venture (see previous post), it is now back on the books again – under the working title of DVB-NGH (for ‘Next Generation Handheld).

Asked whether DVB-T2 – which has always encompassed advanced mobile broadcast capabilities as well as high-capacity fixed HDTV ones – mightn’t itself play the role of a DVB-H substitute, Siefert conceded that “maybe [DVB-NGH] is only DVB-T2. The elements of DVB-T2 are a good candidate.”

On the face of it, this might make good sense: operators in some countries are already looking upon robust profiles of DVB-T as a potential substitute for DVB-H, simply because such implementations re-use a pre-existing transmitter network.

Equally likely, perhaps, would be DVB-T2 with ‘add-ons’ – for instance, DVB-NGH could contain DVB-T2 plus LGE (4G) elements – or, indeed, it could end up as something entirely separate from DVB-T2, Siebert said.

In any event, the next DVB Technical Module meeting is expected to give the go-ahead to a new technical group which will decide what NGH will be based on.

At that same meeting, a study group will be reporting back on current industry 3D developments (very much the theme of this year’s IBC show) with a view to a decision being reached about what DVB’s role should be in the 3D standardisation process, if any. Siebert suggested DVB come contribute elements to do with service information and transport protocols.

Siebert said there was also an ongoing discussion going on between the HBBTV backers (see previous story) and DVB as to “whether DVB should play a more active role” in the hybrid DVB standardisation space, perhaps acting as an umbrella group for various industry initiatives.

Amongst other recent developments, nine European operators, including the likes of Kabel Deutschland, Kabel Baden Wittenberg, Ono and Com Hem, have now committed themselves to the next-generation version of DVB’s cable standard, DVB-C2. Siebert commented that in Germany in particular, cable operators were running out of capacity, so they required the extra capacity DVB-C2 could offer. As an example, he pointed to the fact that Kabel Deutchsland’s RFPs now contained questions about whether set-top box manufacturers were able to support DVB-C2.

The first DVB-C2 prototypes are due to be shown at the Anga Cable show in Germany next year, and IBC 2010 would certainly feature the technology, Siebert said.