Forum pushes spec to unify home nets efforts

A group of companies that hopes to define a standard for chips that drive gigabit-class networking on coax, phone and power lines by 2009 has been launched as the HomeGrid Forum. While the ambitious effort could help unify and expand the rapidly emerging but fragmented market for home networks, huge technical and political hurdles lie ahead.

Eleven companies launched the HomeGrid Forum. They aim to accelerate and drive to market the work of the International Telecommunication Union's G.hn committee to define a standard for PHY and MAC chips.

HomeGrid members believe the spec could replace the fragmented efforts by groups such as the Multimedia over Coax Alliance (MoCA), the HomePNA Alliance and the HomePlug Powerline Alliance. HomeGrid founders Infineon, Intel, Panasonic and Texas Instruments have little or no stake in the existing approaches and stand to benefit from a unified standard that accelerates home networking and potentially makes it a commodity.

"We are all aware there is a fragmented wired [home networking] market today, and a number of companies would like to get to a common technology," said Matthew Theall, president of HomeGrid and a technology strategist at Intel. "This technology could be embedded in hundreds of millions of products someday."

Meetings, marketing
HomeGrid will host weekly technical work sessions to speed progress on the ITU effort, which was launched in 2006 and typically conducts work sessions monthly and face-to-face meetings quarterly. In addition, the forum will take on marketing and certification roles to make sure the resulting standard is adopted, much as the Wi-Fi Alliance has done for the IEEE 802.11 specs.

The forum initially invited a handful of core members that agreed to join, including Aware Inc., DS2, Gigle Semiconductor, Ikanos, Pulse-Link, Sigma Designs and Westell. About 35 companies now participate in G.hn, said Theall. They include powerline chip maker Intellon, as well as CopperGate, which designs chips for the HPNA standard.

"We expect many of the G.hn members will also join this effort," he said.

Imran Hajiumusa, VP of broadband access at Infineon Technologies North America, added, "After the HomeGrid launch, we will reach out to more people to create the momentum and critical mass we need."

ITU G.hn group chairman Les Brown, a senior standards manager for Infineon, said, "This is an ambitious effort, but I think it's necessary; otherwise, consumers might face the prospect of home networking products that not only don't interoperate, but actually interfere with each other."

Supporters note that the ITU helped settle combative debates on standards such as DSL. "It is challenging, but if any one can do it, it's the ITU," said Barry O'Mahony, a senior staff systems engineer at Intel who works with the G.hn group.

The ITU drafts standards by agreeing on technology building blocks one at a time. In comparison, the IEEE calls for complete proposals, often generating competing proposals that battle for dominance.

"The ITU is a better forum for this work, because the IEEE is too much of a beauty contest," said Chano Gomez, VP of technology and strategic partnerships at powerline chip maker DS2, which is locked in a contentious debate over powerline standards in the IEEE 1901 group. "It's more likely that a final ITU standard is one that no one is completely happy with, but that no one gets an [unfair] advantage from."

If successful, the HomeGrid/G.hn effort could encourage consumer electronics and STB makers to sprinkle home network links generously across their product lines.

"We haven't seen a lot of CE companies dip their toes into the home networking space, because from their point of view, there's still a lot of uncertainty about all these competing specs," said Kurt Scherf, senior analyst with market watcher Parks Associates. "I think the connected STB could benefit the most from this move."

Home network ubiquity
Parks Associates estimates about 140 million homes worldwide now have some form of basic home network that includes at least a router and access point. It expects that to grow to as many as 240 million homes by 2012.

Today most home networks in the United States use Wi-Fi (53 percent), followed by wired Ethernet (28 percent), according to Parks. MoCA has 10 percent of the market, and the remaining percentage points are split between Powerline (8 percent) and HPNA (1 percent).

The G.hn committee has made several technical decisions, especially for its PHY spec, but many issues are still outstanding, particularly regarding the media-access controller (MAC).

One of the more important decisions to date has been to target a maximum data rate of 1 Gbit/s. The committee also accepted a target of supporting at the application layer 400Mbit/s on at least 99 percent of coax lines and 250Mbit/s on 95 percent of powerline connections.

Today, MoCA supports 175Mbit/s across 97 percent of installed coax lines and is working on a next-generation spec for 2009 of 400Mbit/s or more. The HomePlug AV spec supports data rates of about 200Mbit/s and is also working on a next-generation spec believed to target 400Mbit/s or more.

Positioning G.hn
"We did not want [G.hn] to be a duplication of existing technologies; rather, we wanted to position it as a next generation with performance beyond today's versions of MoCA, HomePlug and the others," said O'Mahony of Intel.

The G.hn group has chosen a discrete Fourier transform version of OFDM as its modulation scheme. In addition, it will embrace both parameterized and prioritized QoS approaches.

The group has yet to define the number of bands it will support and which frequencies it will use on different media. Powerline and HPNA typically operate below 50MHz, but many cable and satellite TV networks on coax carry some traffic in ranges from 860MHz to 2,159MHz.

"We've done a fair amount of work on the PHY layer, but we have much more to do on the MAC," said Brown of Infineon. "We are talking about a two-phased approach where we focus on the PHY this year and the MAC next year."

Among controller issues, he said, "there's been no work on security yet, and that's a huge hole left to fill."

HomeGrid member Pulse-Link has been defining versions of its UWB technology for use over multiple media, including coax. Pulse-Link president Bruce Watkins said the G.hn group needs to define dynamic methods for setting transmission power and equalization levels to handle the very different characteristics of the media it targets. It will also have to decide how much intelligence to pack into its MAC.

"Recognizing different devices on different media requires a level of complexity and foresight in the MAC that isn't in the existing technologies," Watkins said.

Time considerations
Political issues are likely to be as significant as technical ones, as the many competing players try to drive consensus. Gomez of DS2 said carriers AT&T, Verizon and Qwest want the work to be wrapped up by the end of this year, which some observers say is unrealistic.

The extent of support for the G.hn effort ranges widely, especially among home network chip makers that would be most affected by a technology shift.

"[G.hn] will become the single universal wired home networking standard worldwide," said Richard Nesin, president of the HomePNA group and VP of marketing for CopperGate Communications, the sole maker of HPNA chips. He vowed that a future version of today's HPNA 3.1 spec will support the G.hn standard.

Gomez of DS2 said G.hn is technically feasible, but he took a wait-and-see stance on its likelihood of success.

Both Gomez and Oleg Logvinov, chief strategy officer of the competing HomePlug group, were among many who suggested the G.hn effort will likely take longer than the year that top HomeGrid officials target.

"G.hn is a very good and natural direction for the industry as a whole to evolve the technology," said Logvinov, who filed patents on home network technologies for multiple media earlier in his career. "But this is not something which can be done quickly."

Anton Monk, chief technologist for MoCA, said he is monitoring the G.hn work but suggested the effort is impractical. "You could ask why we don't have one PHY for all wireless networks, too," Monk said. "The answer is there are different cost and performance and other user requirements for different wireless networks."

Watkins of Pulse-Link believes all sides will have to be flexible for G.hn to succeed. G.hn members may have to revisit some decisions, such as their choice of OFDM modulation, which conflicts with his company's approach.

"OFDM has been seen as so good, some people have turned it into a religion," said Watkins. "If you really want to solve a problem, the best idea is to start with a clean sheet of paper. We hope people are willing to do that."

- Rick Merritt
EE Times