LONDON A senior director of DS2, the Valencia, Spain based specialist in silicon for broadband power line gear, has warned of confusion and frustration in the industry and amongst consumers if forthcoming votes on a standard for the technology fail to resolve the problem of a fragmented powerline networking industry.
The standards debate has been raging for almost three years.
Chano Gomez, VP of Marketing at DS2, comes down firmly on the side of the ITU-T G.hn standard which, he maintains, offers the best and fastest solution. Once adopted, compatible networked-consumer electronics devices such as set top boxes, routers, TVs, Blue-Ray players could reach the market as early as next year, Gomez says.
He argues that the IEEE P1901 group's approach is much less likely to succeed, since it is built round multiple incompatible PHYs and MACs. One of the specifications is based on orthogonal frequency-division multiplexing (OFDM) 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.
The ITU is set to vote on the proposals at a meeting in Geneva next week, while the IEEE standardization group is scheduled to make a decision next month.
The ITU-T G.hn standard on the table, Gomez stresses, offers single-PHY/MAC architecture and looks to consolidate all wired networking " powerline, phoneline and coaxial cable " under the same unified umbrella.
But complicating matters is that the coding technique used by G.hn will not interoperate with technology used by the HomePlug Powerline Alliance, whose members already have managed to get several million units deployed in homes.
The HomePlug group is working on an AV 2.0 standard that could be completed by early next year, specifying throughput of up to 600 Mbits/s at the application layer and a Gbit/s at the physical layer. The G.hn spec also aims at a Gbit/s physical layer, although the group has not articulated an exact target for application layer throughput over noisy power lines.
The architecture of the G.hn 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.
"In a home network with coaxial cables, it's 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," says Gomez.
He adds there is broader industry support for the ITU proposal, with, apart from DS2, other silicon vendors developing ICs.
And, he notes, the 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 program to ensure that G.hn-based products interoperate.
He cautions that 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 on Wavelet P1901 he/she would find that it does not interoperate with his/her powerline-enabled router based on OFDM P1901.
"The result [will be] customer frustration, disappointment and either the TV, the router, or both being returned, which will be a problem for both retailers and service providers. The IEEE's current dual-PHY standard also creates problems for device manufacturers and semiconductor companies," says Gomez.
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