Debate over powerline home automation standards

A number of options will be voted on in October to fix the problem of a fragmented powerline networking industry in the forthcoming ITU-T and IEEE meetings.

Chano Gomez, VP of Marketing at DS2, a supplier of high-speed powerline communications technologies, believes the ITU-T G.hn standard offers the best and fastest solution. Once adopted, compatible, networked consumer electronics devices, such as set-top boxes, routers, TVs and Blu-ray players, could reach the market as early as next year.

“On one hand is the IEEE P1901 approach, built on multiple incompatible PHYs and MACs,” says Gomez. “One specification is based on OFDM (orthogonal frequency division multiplexing) modulation; another is based on Wavelet modulation. The modulation schemes are mutually incompatible, so IEEE P1901 products based on OFDM modulation will not interoperate with products based on Wavelet modulation.

“The ITU-T G.hn standard, on the other hand, offers single-PHY/MAC architecture and looks to consolidate all wired networking - powerline, phone line and coaxial cable - under the same unified umbrella. Its architecture was specifically developed to meet specifications common across all three types of media; and its physical medium dependent (PMD) sub-layer is designed to optimise performance in each medium.

“The rationale is that the optimum parameters, eg, frequency bands or power levels, are not always the same for all media. In a home network with coaxial cables, it’s often desirable to operate in the 800-1600 MHz band, while the preferred frequencies for power lines are usually well below 100 Mhz. In these circumstances, the G.hn MAC would provide support for both guaranteed bandwidth reservation and best-effort service, which will accommodate the requirements of a wide range of video, audio and data applications.”

The HomeGrid Forum, an industry group that has Intel, Panasonic, Best Buy and British Telecom as board members, actively supports the G.hn standard and is developing a comprehensive Compliance and Interoperability program to ensure that G.hn-based products interoperate.