Original URL: http://www.theregister.co.uk/2011/01/12/ieee_1901_itu_ghn/

Silicon to stop next-gen powerline standards war

Will the mains networking biz put its squabbles behind it?

By Tony Smith

Posted in Hardware, 12th January 2011 14:19 GMT

Powerline networking, which uses ubiquitous home electrical wiring as a pipeline for data, has had a hard time winning popular support. Wireless networking has grabbed most of the public's mindshare, largely thanks to the Intel marketing machine. And the mains wiring technology has struggled with the industry's inability to rally behind a single standard during its evolution through 14Mb/s, 85Mb/s and 200Mb/s incarnations.

Faster speeds are coming, but powerline proponents are still worried that the existence of two, new competing standards for the next generation of Ethernet-over-mains technology will see a continuation of the current standards war.

The two rivals are the IEEE's 1901 and the ITU's G.hn. Both are designed to more than double the performance of today's 200Mb/s powerline links, the better to allow punters to send multiple 1080p HD video streams around the home simultaneously. Get that right and almost any other kind of data consumers want to transmit will easily fit into the available bandwidth.

Both have powerful backers. The HomePlug Alliance, overseer of the HomePlug AV 200Mb/s standard, has given its thumbs up to 1901, not least because 1901 is compatible with its own technology.

The IEEE standard also incorporates HD-PLC, a powerline technology developed in Japan but which is very similar to HomePlug AV. HD-PLC uses wavelet compression; HomePlug uses Fast Fourier Transform to do the same job. In other respects, the two specifications are effectively the same. For that reason, 1901 combines the two.

HD-PLC is relatively unknown in the West - though it's big in Switzerland, says Dr Stephan Horvath, CEO of local technology company Advanced Communication Networks - where HomePlug AV has become the de facto standard after beating a rival offering from the Universal Powerline Association.

The UPA effectively collapsed last year when its main backer, Spanish chip company DS2 shut it doors. Before its demise, DS2 had been looking to G.hn as the next step in powerline networking.

It wasn't the only one. The world's biggest chip maker, Intel, has lent its support to the standard, which is being promoted by the HomeGrid Forum. The Forum is backed by a fair few service providers, including BT.

Battle lines drawn - where are the mediators?

With big names on both sides, the stage is set for the inevitable 'standards war', a conflict companies backing either technology appear to be keen to promote.

Ironically, the market for powerline products remains well short of its potential, leading some commentators, such as David Waks of long running powerline news site Broadband Home Central, to throw their hands up and wonder why the likes of the HPA and HGF aren't working together to expand the market to the benefit of both.

That may yet happen, albeit indirectly. According to Jean-Philippe Fauré, head of the IEEE team charged with turning 1901 from a notion into a specification and then formalising it as a standard, interoperability provisions built into both 1901 and G.hn will ensure that the two standards can happily co-exist.

Co-existence is not compatibility, of course, but it ensures that if you put in place a 1901-based powerline network, the G.hn-based adaptors bundled with your broadband box by your service provider can be used too, without killing both LANs.

Fauré told Reg Hardware that both standards have agreed measures by which they will equally share the available mains bandwidth in the 2-30MHz band.

All very well for new 1901- and G.hn-based adaptors, but older HomePlug AV and UPA kit, all of which lack the co-existence tech, will likely kill them. Moral: if you upgrade one box to 1901 or G.hn, upgrade them all. This is not likely to be expensive.

And it may not be necessary to choose one new standard or the other, says Fauré. Mobile phone chips already support numerous networking technologies, each with distinct physical links - the so-called PHYs - and do so happily.

Savvy powerline chip makers can do the same, building support for both G.hn and 1901 into their products, allowing adaptor A to talk to adaptor B no matter which of the two standards the latter is dedicated to.

The G.hn specification contains one PHY, but 1901 has two. A three-PHY chip is not hard to do.

None of the chip makers eying either standard have yet gone public on plans to support both rather than one, but it's a logical step for them to make. The first powerline chip makers were relatively small operators, now long since acquired by big names - Intellon by Atheros, DS2 by Marvell, Gigle by Broadcom - who have the size to take on multi-standard developement efforts and the competitive motivation to do so.

The powerline standards war may yet be called off before the troops march into battle. ®