dab digital radio DMB

Broadcast Asia (Part 2) – Right Technology, Wrong Device

There were quite a few interesting things to see at Broadcast Asia, not least the dazzling array of new mobile phone devices heading their way to Europe. You can go for bling, or sleek, or chic or geek. You can get originals from Samsung, LG, SonyEricsson or get knockoffs from ZTE. What’s true for all of them is that it’s highly unlikely that you’ll pay anything like the true cost of them up front. The handset subsidy model is well established across most of the EU states, where you get a £400 / €650 handset for free in return for signing an 18 month contract at typically £30 / €50 a month.

This is relevant when you think about how to transmit radio digitally.

MBMS is a broadcast mode for 3G networks. Using unpaired carriers, it’s possible to simply broadcast multi-cast IP packets to handsets by enabling selected existing 3G sites to transmit the carrier, and creating a Single Frequency Network. (This almost identical in concept to IP Multicasting over DAB Digital Radio). When you lose the multicast carrier, the handset simply swaps back to normal 3G unicast mode and vice versa. This seems like the perfect method for “broadcasting” (streaming) radio to mobile phones, and from the networks’ point of view, it almost certainly is.

Meanwhile, over in France, a decision is being made to transmit radio using a variation of the DMB Mobile TV specification called “DMB Audio“, rather than the existing DAB or DAB+ specifications. DMB Audio is the DMB TV specification “adapted” to remove the requirement to transmit a video component, working on the assumption that (TV – Audio) = Radio. Despite the fact that no other country is showing any interest in this Frankenstein technology (c.f. SECAM), and that it delivers a lousy radio experience, there is one compelling reason to reject it (and MBMS and DVB-H) for radio transmission, and it’s one that everyone seems to have overlooked.

Try building a £30 / €50 kitchen radio for MBMS, DMB Audio or DVB-H.

Whilst these technologies can transmit audio, they’re primarily designed to transmit video and phone calls and a whole load of other things which dramatically raise the lowest point of entry to the technology. That means you simply can’t build a cheap and simple radio that will shift in its millions, and critically, can sell at a reasonable price without a subsidy or a contract. DMB-T is interesting because it was an extension of a simple technology to do a more complicated job. “DMB Audio” is the worst idea ever because it’s a complicated technology only using a portion of its capabilities.

It’s true that most modern digital broadcast systems can carry audio services. But that doesn’t mean they’re good technologies to transmit radio to the population as a whole, technologies that can span cheap radios in kitchens through to fully integrated multi-media receivers in mobile phones.

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