900 MHz Interference Fight Seen as Key for Other Unlicensed Spectrum
The Telecommunications Industry Association and the Consumer Electronics Association warned that “spectrum etiquette” rules proposed for the 902 to 928 MHz band could stifle innovation and would be bad for the other major unlicensed bands, as well as the future of wireless broadband. But the American Petroleum Institute, the Utilities Telecom Council and the Association of American Railroads warned that taking no steps would pose risks to the band and the hundreds of millions of devices that use it every day.
Sign up for a free preview to unlock the rest of this article
Communications Daily is required reading for senior executives at top telecom corporations, law firms, lobbying organizations, associations and government agencies (including the FCC). Join them today!
“The proposed requirements would turn Part 15 on its head by requiring protection of the new class of ‘incumbent unlicensed devices’ at the expense of new and innovative uses, including low-cost rural broadband access solutions,” TIA said. “In addition, the requirements would significantly constrain design flexibility and increase the cost of unlicensed equipment. The costs of such tradeoffs exceed the promised benefit of interference reduction.”
The frequencies at stake were the first major block of unlicensed spectrum made available by the FCC. Cordless phones, baby monitors and automatic meter reading equipment used by utilities share the band. Oil producers use the spectrum to control operations in the field and gas companies to control valves that shut off the flow of gas to a damaged pipeline. “When you start to talk about the success of the unlicensed band, it started here,” said an attorney for a company that supports new rules. “There are hundreds of millions of devices that operating on frequencies in this band.”
Commenters that favor spectrum etiquette rules put part of the blame on the FCC. Historically, most devices used low power and until 2002 operated under rules requiring Part 15 devices in the band to occupy a specific channel or frequency just long enough to communicate and then release the channel. But then the commission changed its rules to allow new digital transmission technologies and spread spectrum systems to use the 902 to 928 MHz band - opening the door for wireless ISPs, including customers of the Canopy technology sold by Motorola, to use the spectrum.
Cellnet, which manufactures meter-reading equipment, in 2004 asked the commission to require, consistent with “its long-standing policy,” spectrum etiquette rules specifically for the band - among them that part 15 devices be “constructed in accordance with sound engineering and manufacturing practices” and suppress emanations “as much as practicable.” The commission sought comment.
Itron, which also manufacturers meter-reading equipment, agreed with Cellnet that the FCC must impose some rules. “As high power, ‘always on’ devices continue to proliferate, incompatibility problems are getting worse and the overall noise floor of the band is increasing,” the company said. “Part 15 manufacturers now must contemplate operating at higher power solely to overcome interference from digital modulation systems -- an escalation that itself can create a ’tragedy of the commons.'”
Itron disagreed sharply with arguments that new rules would hurt development of a new generation of devices. On the contrary, “spectrum etiquette would free device manufacturers from devoting time and resources to defensive engineering or re-engineering in order to address ongoing interference and spectrum access issues,” Itron said. Imposing stricter rules “would allow manufacturers to devote additional resources to new design and other innovations.”
The API and the UTC said the interference from digitally modulated systems “has not yet reached critical mass,” but is already emerging as a major problem for other users of the band in some parts of the country. “It is absolutely essential to the energy industry that the Commission adopt a sustainable spectrum management policy for the 902-928 MHz band,” the groups said. “It is also critical to the Commission itself to ensure the continued viability of license-exempt operations.”
Motorola, which manufactures the Canopy system, which is used to offer wireless broadband in the band, said the etiquette rules would have unintended consequences. “Imposition of a spectrum etiquette in these bands will have a devastating effect on delivery of important services, including the cost effective delivery of rural broadband services, that have flourished under the existing rules,’ Motorola said. “Second, the Commission has properly established a precedent of minimal regulation in unlicensed bands, noting that by allowing manufacturers flexibility in designing their products, such manufacturers have developed their own, highly effective sharing and modulation schemes.”
The Wireless Communications Association said the FCC has specifically refused to impose spectrum etiquette, a decision Cellnet asked it to reconsider. “Unlicensed spectrum has been a success story due to Commission policies that promote flexibility,” the WCA said.