ITU-T G.hn vs IEEE P1901 - 01 Oct 2009


We have the IEEE P1901 approach, which is built on multiple incompatible PHYs and MACs. One of the specifications is based on OFDM (Orthogonal frequency-division multiplexing) modulation; the other 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.

Then there is the ITU-T G.hn standard that offers single-PHY/MAC architecture and looks to consolidate all wired networking - powerline, phoneline and coaxial cable - under the same unified umbrella. Its unique 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 optimize performance in each medium.The rationale for the PMD is that the optimum parameters. In a home network with coaxial cables, it is sometimes desirable to operate in the 800-1600 MHz band, while for power lines the most attractive frequencies are usually those 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 application.

Broader industry support comes from multiple silicon vendors, including DS2. HomeGrid Forum, an industry group that has Intel, Panasonic, Infineon, Sigma Designs, Best Buy and British Telecom as board members, are actively supporting the G.hn standard and is developing a comprehensive Compliance and Interoperability (C&I) program to ensure that G.hn-based products interoperate.

If the IEEE P1901 standard were to be approved in its current format, then when a consumer buys a TV with embedded powerline technology based onWavelet P1901 they would find that it does not interoperate with their powerline-enabled router based on OFDM P1901. The IEEE's current dual-PHY standard also creates problems for device manufacturers and semiconductor companies.

Once the ITU-T G.hn standard is completed, we can expect a wide range of G.hn-compatible networked-consumer electronics devices to include Set-Top Boxes, Routers, TVs, Blue-Ray players, etc. to reach the market in 2010.

Smart Grids Home page