HomePlug Eyes Power-Line-Based LAN, WAN Interoperability

San Ramon, Calif. — The HomePlug Powerline Alliance plans to develop a Broadband-over-Power Line (BPL) standard that electric utilities could adopt to deliver broadband Internet access and other services over their existing power-line grids to homes and businesses.

The association's goal is to create a HomePlug BPL standard that delivers interoperability between BPL modems and home-network gear based on HomePlug's 14Mbps 1.0 standard and almost-completed 200Mbps A/V standard. If interoperability is achieved, a home's central BPL gateway could communicate with HomePlug-equipped PCs and consumer electronics devices via a home's existing electrical wiring.

The alliance is “hopeful” that its planned BPL standard will be adopted by utilities, said Oleg Logvinov, president of the Alliance and semiconductor developer Arkados. No other industry-wide standard is currently under development, he noted.

The alliance stands a chance of developing a BPL standard in part because BPL-technology developers and two utilities are already alliance members. About a half-dozen companies have developed BPL technologies, and most of them are alliance members, said Jim Reber, chairman of the alliance's marketing working group. Although only two utility companies are members, “we're inviting more,” Reber added.

HomePlug is currently writing a market-requirements document (MRD) to solicit recommendations for a BPL standard, said Charlie Harris, HomePlug's board member and Intellon's CEO. The MRD will be finalized by late November. Typically, it takes a year from MRD completion to develop a standard, he said.

Although Logvinov believes prospects are high for utilities' adoption of a HomePlug BPL standard, electric companies have already been holding large-scale trials of multiple proprietary BPL technologies. In fact, select utilities have tested four or five technologies. Despite such tests, however, “I don't believe any service deployment can be based on proprietary technologies,” Logvinov said. He cited the example of a cable-modem standard that accelerated broadband-cable deployment. “I don't believe any service deployment can rely on a single-source technology. It's too dangerous.”

Current BPL technologies deliver data at DSL-like speeds of 250kbps to 1Mbps to a house, said Harris.

If utilities don't adopt a HomePlug-based BPL technology, the alliance has formulated Plan B. That plan would implement measures to prevent interference between HomePlug networks and various proprietary BPL technologies that individual utilities might adopt. Such interference would slow down the speeds of HomePlug- and BPL-based networks within a home, given that each network would operate within the same 2MHz to 30MHz frequency band. The magnitude of the network slowdown, however, “is impossible to predict,” said Logvinov, because it depends in part on the technology used.

Without such interference-prevention measures, even consumers who don't subscribe to BPL service would see their HomePlug home networks slow down because BPL signals would leak into their home wiring from outside utility wires, Reber said. To block the BPL signals, consumers would have to install a filter by their circuit breaker box.

For these reasons, the proposed HomePlug A/V home-network spec includes “hooks” that could also be integrated into non-HomePlug–based BPL technologies. The hooks would enable HomePlug and BPL devices to share a home's power lines in the time or frequency domains, said Reber. The addition of one HomePlug A/V device into an existing HomePlug 1.0 network, he noted, would prevent interference between HomePlug 1.0 devices and BPL signals.

If utilities adopt non-HomePlug technologies, then Logvinov believes the utilities would require their BPL technology providers to include the hooks. “Would a utility deploy a technology that would potentially cause their users to cancel [BPL] service? Probably not,” he said.

HomePlug members include equipment makers, ISPs, electric utilities and companies that have developed BPL technologies, most of them currently incompatible with HomePlug 1.0 and the planned HomePlug A/V. One BPL-technology developer, however, has implemented a HomePlug 1.0-based BPL technology. That company, Current Communications, has commercially deployed its technology with Ohio utility Synergy. Current's “signal rolls directly to the home and is compatible with any HomePlug 1.0 product,” said Intellon's Harris. Current's system is based on Intellon's HomePlug 1.0 chips.