Fixing the UK's DAB disaster

Beyond the bubbling mud

By Steve Green • Get more from this author

Posted in Music and Media, 2nd April 2008 09:44 GMT

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The lure of multicast

The BBC is also due to launch multicast (one-to-many IP streaming) this year. This promises to deliver stations from the BBC and a number of commercial rivals at higher quality than DAB+ is ever likely to.

Multicast is a key technology for delivering live TV channels on IPTV platforms, as it's so bandwidth-efficient. But it's received little support from ISPs up to now, because ISPs are still being heavily reliant on BT's network, and BT's current network doesn't support multicast.

BT has recently demonstrated delivering video using multicast over its shiny new 21CN next generation network to assembled journalists though, and Sam Crawford, who's behind the Samknows Broadband website, said he'd be massively surprised if [BT] didn't release [multicast] or at least announce it this year".

So with five of the six biggest ISPs either looking to provide, or already providing, IPTV it would be surprising if multicast wasn't widely available to broadband users once BT has rolled 21CN out nationally. That's due to happen by 2010.

A quarter of broadband users will be getting multicast support later this year when Virgin Media launches its 50 Mbps cable broadband package, which will include an HDTV channel called VoomHD that will only be available via multicast.

A technology tragedy

The BBC's radio programmes are also due to be incorporated into the P2P download version of the iPlayer, which should make them available at better-than-DAB+ quality and, if the BBC does invest in a content delivery network (CDN) for the iPlayer TV streams, that would potentially allow the quality of both the TV and radio on-demand streams to be improved because the CDN should significantly ease the bandwidth burden for the ISPs.

The mobile broadband platform is also looking promising, with plenty of investment in high speed data infrastructure. In theory, 3.9G and 4G that are due to be deployed between 2010 and 2015 will offer peak download speeds ranging from 100 Mbit/s up to a few Gbit/s. So if the BBC would allow mobile users to download on-demand files, rather than making people use their slow P2P network, these files could be downloaded very quickly.

These future technologies will have their own version of MBMS (Multimedia Broadcast Multicast Service), the broadcast standard in 3G. So considering that NTT DoCoMo's 4G candidate system is theoretically 223 times more spectrum-efficient at carrying digital radio than DAB and 79 times more efficient than DAB+, any such 4G broadcast standard would inevitably make DAB+ look ridiculously inefficient in comparison. And this in turn would raise serious doubts over the economic viability of DAB+. Ofcom's decision to delay using DAB+ will be seen in years to come as a mark of technology tragedy.

Ofcom's £270,000 per year CEO Ed Richards is said to be concerned about his legacy. Crippling the nation's radio is a sad one to leave us with. ®