IEEE drops support for rival standard from powerline LAN spec

The IEEE-backed attempt to define a universal standard for powerline networking has dropped plans to ensure compatibility with rival world home LAN standard G.hn.

Late last year, members of the IEEE P1901 working group voted to include G.hn, a standard being developed under the auspices of the International Telecom Union (ITU), within the 1901 specification.

But at a meeting held in Boston, Massachusetts this week, the proposed addition of a G.hn-compatible physical and transport layers - PHY and MAC - were removed from the draft specification. Development of the G.hn MAC and PHY will stop.

In some respects, it's a sensible move. G.hn compatibuility was added at the behest of companies who are, by and large, keener on G.hn than 1901.

G.hn uses a single PHY specification to allow networking traffic to be transported over mains wiring, phone cable and coax lines. By contrast, 1901 contains two, incompatible PHY specs, the better to accommodate different working group members' preferences. Both are optional. One implements FFT (Fast Fourier Transform) modulation to ensure compatibility with existing powerline kit that meets the HomePlug standard - which is why the HomePlug Powerline Alliance (HPA) is so keen on 1901. The second PHY adds wavelet compression. It's not HomePlug compatible, but is widely believed to enable more robust, faster data transfer. It comes from Panasonic.

Adding support for G.hn would involve adding a third PHY combo, and clearly the P1901 members have decided two is enough.

Besides, if 1901 offers G.hn support, what's to stop potential backers from equipping kit only with G.hn but still claiming compatibility with both standards? Or, for that matter, bothering with 1901 at all?

Now they will have to, and the P1901 group has ensured its standard is less likely to become in irrelevance, at least for home networking. The standard also takes in routing broadband feeds over mains cabling into the home. ®