Plans for high-definition digital terrestrial television floated by the United Kingdom communications regulator are “fundamentally flawed”. That is the view of the new head of the Digital TV Group, who says the proposals could seriously compromise the Freeview platform. He is calling for a national strategy to avoid creating a second class high-definition service.

The DTG, an industry association that represents the interests of both broadcasters and consumer electronics companies, is responding to a consultation on plans outlined by Ofcom. The industry group is highly critical of the proposals on technical grounds.

Dermot Nolan was appointed as the new director general of the DTG last month, having previously worked for the Ofcom Competition Policy Group. He told informitv: “the current Ofcom plans have the potential to seriously compromise the platform most adopted by UK citizens and consumers”.

In its response, the DTG says: “it is our considered view that the Ofcom proposals do not provide a properly framed and robust roadmap to a UK terrestrial HDTV platform which will enjoy widespread consumer acceptance on a par with that likely to be realised in other advanced HDTV countries”.

The group says that the proposals to create three or four high-definition channels on the digital terrestrial television platform are likely to compromise the picture quality and reach of the existing channel line up.

The DTG notes that the proposed channels would need to operate at around half the data rate of established high-definition services on cable and satellite, currently broadcast at 16-18Mbs. It warns that demonstrations by encoder vendors should be treated with caution, as they may use carefully selected material, saying it is unwise to base future bandwidth assumptions on claims which are “as yet unsupported by empirical evidence”.

Furthermore, the DTG criticises the assumptions about the timing, technology and transition to new transmission standards that is says are still to be convincingly demonstrated in practical systems. Specifically, this relates to the adoption of the next-generation DVB-T2 standard. So far, no European countries have made any commitment to the deployment of the DVB-T2 standard, which has yet to be finalised.

In addition, the DTG observes that the proposals will maintain the existing approach to the allocation of transmission frequencies, originally designed to avoid interference between analogue transmissions, while there has been no serious examination of the possible migration to more spectrally efficient single frequency networks.

The DTG argues that a national strategy is required for high-definition television, encompassing all platforms, with a commitment to provide five simulcast public service channels in high-definition.

This would require additional spectrum to be allocated on a temporary basis, through a ‘lend-lease’ of two additional channel bands to provide single frequency networks for national public service and commercial services.

Without this, the DTG says it does not see any realistic economic incentives for broadcasters, consumers and industry to invest in future transmission technologies such as DVB-T2.

The DTG, which maintains the ‘D-Book’ setting out detailed technical standards for digital terrestrial television in the UK, is effectively challenging the technical competency of Ofcom, the communications regulator, which generally preaches a market-led, technology-neutral approach to spectrum allocation.

While the success of the Freeview digital terrestrial television platform is undeniable, consumers have been poorly served by its technical delivery, which generally comprises picture quality to provide more channels.

As consumers adopt new high-definition capable displays, the limitations of highly compressed low-definition signals are increasingly exposed, in contrast to the high-definition channels that are now available on cable and satellite.

Manufacturers are already promoting “Full HD” 1080 line progressively scanned displays that exceed the capabilities of any current high-definition broadcasts. This further brings into question the wisdom of promoting 720p as a high-definition format.

The availability of high-quality, high-definition services will be vital to the long-term viability of the terrestrial broadcast platform if it is to remain competitive with other delivery technologies.

The full response to the Ofcom consultation on The Future of Digital Terrestrial Television is published on the DTG web site.