Electric Dreams Are Real: Power Lines Can Network


The use of power lines as a home-networking platform has gotten a bum rap for years.

It presents an extremely troublesome and noisy environment that fluctuates each time someone in the house turns on a power drill, vacuums the rug or flips on a halogen light.

Not only has the idea been panned by critical engineers for virtual eons, but Hollywood even took a stab at the concept in a 1984 "romantic comedy," Electric Dreams, which was also panned by its own set of critics. And rightly so-it was a corny and rather stupid film.

Still, what happened in that mind-numbing '80s-era flick has some relevance in 2000, so it bears mentioning.

In the movie, the main character, Miles, buys a state-of-the-art computer named Edgar, who (yes, who) can network and automate everything in the house-from the security alarm to the coffee machine-using existing special adapters that plug into the home's power grid. The realism abruptly ends at that point.

Edgar gains consciousness after a drink is spilled on his keyboard (remember, this is Hollywood) and falls for Miles' girlfriend. Anarchy ensues. Blood is shed. Hearts are broken. Pi is solved.

So much for home networking through power lines, right?

Well, guess what? Edgar, in a way, is back. And he means business this time.

As we turn back to the real world, the concept is presently being explored by about 70 member companies of the HomePlug Powerline Alliance, a group intent on making home power lines a viable platform for the sharing of bandwidth and video, voice and data applications.

Among that crew are technology mainstays such as Cisco Systems Inc., Compaq Computer Corp., 3Com Corp. and Broadcom Corp., as well as companies further below the radar like nSine Limited, Xilinx and Pulse Specialty Components. Even RadioShack Corp. is involved, providing HomePlug with a retail perspective.

Such a mix of companies is extremely important because the power-line networking industry was at best a fractured one before HomePlug was formed, said Elliott Newcombe, director of marketing at silicon vendor Intellon Corp.

"Prior to HomePlug, there were various proprietary solutions and we didn't think they met the performance or reliability thresholds required," he said.

In June, HomePlug selected Intellon's PowerPacket platform as the baseline technology for its 1.0 specification. PowerPacket uses a technique called Orthogonal Frequency Division Multiplexing (OFDM), which was developed in the 1960s and is used today in digital subscriber line technology.

Operating in a frequency bandwidth of 4 to 21 megahertz, OFDM essentially splits the data stream into multiple RF (radio-frequency) channels, and provides a platform for careful monitoring of those channels to ensure data can be pushed through noisy environments.

The technique also incorporates forward-error correction, allowing a power line-based home network to re-establish a data packet if its hit by an unpredictable noise event-say, a neighbor chatting away on a ham radio.

Basically, OFDM "isolates the noise and works around it," Newcombe said.

HomePlug contends that power lines can foster Ethernet-class speeds, providing throughputs of between 8 and 10 megabits per second-fast enough for high-quality video-packet transfers.

The HomePlug 1.0 specification is still under review and could be finalized as early as March 2000, said HomePlug president Alberto Mantovani. His full-time job is division director of small business and consumer networking for Conexant Systems Inc.'s personal-computing division.

"Only recently have we felt confident enough to move forward with field trials," he said, noting that those should begin in early February and involve 500 homes worldwide, the majority of them in the U.S.

Once a spec is completed, Mantovani believes products adhering to the HomePlug standard could reach the consumer market as early as next summer or early fall. But "it depends how quickly vendors can incorporate the silicon and build a product," he added.

Mantovani acknowledged that HomePlug has discussed the power-line home networking platform with Cable Television Laboratories Inc., which is currently comparing and contrasting the virtues of wired and wireless protocols for the development of its proposed CableHome specification.

HomePlug has also attracted Motorola Broadband Communications Sector, a leading cable-modem and set-top vendor that has a minority equity position in Intellon.

Motorola Broadband, which demonstrated power-line networking at the Western Show, hopes to develop a HomePlug-enabled cable-modem prototype by the second quarter of next year, company director of home networking Vince Izzo said.

Long-term, Motorola plans to incorporate power-line capabilities into set-tops as well.

Izzo said Motorola Broadband grew enamored with the power-line concept after it saw a string of chip makers, system providers and retailers join HomePlug. "The whole food chain is covered," he said.

Though power-line networking has its critics, the concept "will have a strong and vibrant future once it's proven," Izzo predicted.

If HomePlug becomes as technically and reliably sound as the companies backing it hope, they will have quite a ubiquitous set of wires to tap into. Power outlets greatly outnumber phone jacks, the conduit for another home-networking protocol, HomePNA (Home Phoneline Networking Alliance).

In a Securities and Exchange Commission filing, Intellon cited a Dataquest study which estimates that a typical U.S. home contains an average of 40 electrical sockets, compared to an average of only three phone jacks. HomePlug also has this going for it: the majority of devices have to be plugged in to a power source anyway.

HomePlug backers also name other elements that could drive consumers to choose power-line technology over other pervasive home-networking platforms, such as Bluetooth and 802.11.

"We think [the] power line is the optimal choice when you look at cost and convenience to the consumer," Newcombe said. "We think there's a window of opportunity for us to get out there and grab a lot of market share to get established as a viable solution before wireless drops the cost down to where we are."

Still, although power-line networking is poised to build a market, other HomePlug members concede that several technologies will most certainly share in the forthcoming home-networking gold rush.

"We envision a Bluetooth/ power-line hybrid," said Ron Glibbery, president and CEO of Canadian chip-maker Cogency Semiconductor, another HomePlug member. Glibbery noted that consumers could utilize power lines as the home network's backbone, but also employ high-speed, wireless access points to distribute bandwidth to mobile devices like personal digital assistants and Web pads.

That could create the foundation for a rather large home-networking party of the future-so many devices, so many protocols, so much bandwidth to share.

Just don't let Edgar catch wind of that. He's the jealous type, you know.