HomePlug Wraps Trial, but Challenges Remain


The HomePlug Powerline Alliance, the consortium behind a home-networking protocol that taps inherently noisy power lines to share bandwidth and applications, said it has wrapped up its first "large-scale" field trial, testing technology in 500 U.S. and Canadian homes.

Although HomePlug's backers hope that power lines will someday be used to transfer latency-sensitive voice applications and bandwidth-intensive video streams, one cable executive who has seen power-line technology first hand believes it might be better suited for low-bandwidth applications such as home monitoring or security.

HomePlug president Alberto Mantovani said the trial, which began in January using a "friends-and-family" approach, tested nearly 10,000 wiring paths, calculated average throughputs and ran a range of streaming media, file-transfer, voice-over-Internet protocol and Internet-access applications.

Initial tests focused on a two-node arrangement, followed by a more expansive five-node method, Mantovani said. The five-node test simulated a network with a PC/gateway linked to four other PCs located throughout the home, handling multiple transactions and applications, Mantovani said.

Among the experiments: HomePlug ran four VoIP calls and a streaming media application simultaneously, using the protocol's intrinsic quality-of-service features, which ensure that voice and video packets reach their final destination on time.

In terms of pure performance and throughput, the HomePlug trial executed a peak data rate of 8.4 megabits per second, Mantovani said. In about half the cases, the power-line networking trial attained throughputs of between 7.2 mbps to 7.3 mbps, with 1 mbps realized in 98 percent of all cases.

Throughputs of at least 5 mbps occurred 80 percent of the time, he added.

Though HomePlug members must still sift through the trial's documentation, the next focus will be to get the technology out into the market, Mantovani said.

"We'll move from technology development to market development mode over the next six months," he said. During that time, HomePlug and its members plan to educate consumers about the technology, as they prepare to introduce products later this year.

Despite HomePlug's apparent early successes in a controlled environment, some are leery about how power-line networking will act outside laboratory and field trials.

"Although it's an intriguing technology, power-line networking still has some work to do," said Steve Craddock, vice president of new product development at Comcast Corp.'s cable unit. "The thing that bothers me is when they start to stream MPEG over power lines."

Power-line networking will have its place, "but probably not for what [its backers] think it will be used for," Craddock said.

He believes that HomePlug might be better suited for home-automation applications than home-entertainment purposes.

Power-line access "is how I talk to the water heater, it's how I talk to the security cameras, it's how I talk to the refrigerator," Craddock added. "There are a whole set of economics and money that can be made in that business, which has nothing to do with cable, but it's something that can be connected to an always-on network."

Such a service is on Comcast's mind. Earlier this year, the MSO participated in a $45 million, second-round investment in @Security Broadband Corp., a start-up with designs on a cable-based home security service.

Adelphia Communications Corp., Charter Communications Inc., Cox Communications Inc., Rogers Communications and Shaw Communications also took part in that financing round.

Though HomePlug must still convince the cable industry that it offers a viable technology, it's arguably the most widely recognized power line-based home networking protocol. However, some power-line technology vendors aren't giving up the fight for a slice of the pie.

Intellon Corp.'s Orthogonal Frequency Division Multiplexing-based PowerPacket platform won HomePlug's baseline technology bake-off back in June. However, other companies such as Inari and Adaptive Networks are still pushing their proprietary technologies.

They're banking that HomePlug will be bogged down by delays and that its technology will essentially "fall flat on its face," said Navin Sabharwal, vice president of residential and networking technologies at Allied Business Intelligence Inc. "But I tend to think that it won't," he said.

At the same time, HomePlug is going after high throughputs. But some observers, including Craddock, see power-line networking strictly as a home automation play.

Utah-based Inari — which wasn't invited to the original HomePlug bake-off, but has a credible set of backers such as Thomson Consumer Electronics, Hewlett-Packard and Texas Instruments Inc. (which is also a HomePlug member) — offers throughputs of about 2 mbps, though a new version is expected to boost that up to 12 mbps.

To counter Inari's lower bit-rate protocol, HomePlug could eventually complement its original spec with a lighter version, Sabharwal predicted.

Adaptive Networks, a CableHome vendor author, owns a patented technique that fosters a delivered throughput of 5 mbps with built-in QoS, company president Michael Propp said. Adaptive also is taking a "wideband" approach to deliver streaming media and video over home power lines.

He said Adaptive would implement the final phase of its technology by year-end. Adaptive is also working with the Consumer Electronics Association's R7.3 group on a standard that might evolve into a strong HomePlug foil.

While HomePlug has the most momentum in the power-line networking sector, it could hit a rather large speed bump in Europe, Sabharwal said. That's because some utility companies there are already interested in offering broadband services over power lines.

The problem? HomePlug taps into the same spectrum the utilities want to use.

HomePlug knew about the potential conflict, but decided not to work around it, taking a calculated bet that home networking over power lines is more compelling than power line broadband, Sabharwal said.

"The European utilities are upset about this," he added, noting that some have pledged to "block [HomePlug] every step of the way."

Although HomePlug will likely get off to a good start in the U.S., the technology could face a "regulatory ambush" across the pond, Sabharwal said.

That set of circumstances could open a door in Europe for Inari, because its technology could coexist with power line broadband.

Whether HomePlug or a proprietary system makes the most hay, there are still questions as to the technology's consistency and robustness.

But power line-based home-networking systems are still expected to be cheaper than wireless or wireline technologies.

"It's low cost, people want it to work," Sabharwal concluded.