After a decade of hoopla, broadband over power lines was the dark-horse access technology, nurturing high hopes but holding few standardization promises. Then, in midsummer, it appeared to reach critical mass. The IEEE defined a new standardization program in its P1901 effort, "Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications." At the PHY/MAC working group's mid-July inaugural meeting, IEEE participants pledged to work with other standards bodies in the power industry. And on simultaneous fronts, developments elsewhere quickly unfolded:
- IBM Corp. announced a pact with a Houston utility company, Centerpoint Energy, to test last-mile access technologies.
- Google Inc. joined with a consortium of investors to plow $100 million into startup service provider Current Communications Group.
- San Diego Gas & Electric said in late July that it would begin a small pilot project this month, using broadband access internally in its Kearny Mesa, Calif., office to test internally a data service that it might later offer to customers.
- Earlier in the summer, the Michigan Broadband Development Authority closed on a $520,000 loan with Shpigler Group Inc. (Nyack, N.Y.). Shpigler will work with Consumers Energy to provide broadband-over-power line (BPL) services to the mid-Michigan towns of Grand Ledge and St. Johns.
The summer's frantic activity might convince a skeptic that BPL's well-documented problems with external interference from ham radio operators' shortwave transmitters and other sources had been solved. Yet, these problems not only persist but also join other deployment woes that could slow effective adoption of power lines for broadband access.
On the standards front, the HomePlug Powerline Alliance already has defined physical-layer (PHY) and media-access control-layer (MAC) chips for the 200-Mbit/second extension to the in-building networking standard, HomePlug 1.0 + AV (see story, page 6). The alliance has recommended using the same PHY and MAC for the BPL solution. The IEEE's participation could throw a wrench into the effort to find a common base for AV and BPL.
The specific solution developed by Intellon Corp. uses notch filters implemented in silicon to minimize interference with ham radio bands. Intellon is willing to provide designs as a chip-level standard, and system-level OEMs are working on more software-defined notch filters specific to regional installations.
But U.S. vendors contend that the biggest European supplier of BPL chips, DS2 of Spain, has not implemented such filters, and the European body it works with, the Universal Powerline Alliance, has yet to address the issue of high-frequency interference.
Chano Gomez, vice president for technology and strategic partnerships at DS2, contends that his company was one of the earliest proponents of programmable filtering. He said that notch filters implemented in the newest version of DS2 silicon not only meet the FCC's exclusion bands for BPL in the U.S., but can be adapted to meet regulatory requirements for HF radio in many nations, not just U.S. ham bands,
Several potential BPL developers wonder whether electric-utility companies will prove to be effective managed-service providers, even with networking partners. Charlie Raasch, division director for technology planning at Conexant Systems Inc., said his company has offered in-home HomePlug products for the existing 1.0 standard and is upgrading for higher-speed AV extensions for LAN audio and video. But, he said, "we still see a big difference between self-installed, self-deployed home networks and service-provider BPL access. We are following BPL standards, but we are not moving full speed ahead with access products yet."
