WCA Proposes Rules on 2496-2500 MHz Band Sharing by BRS, ISM
To ensure “reasonable sharing” of the 2496-2500 MHz band by BRS and unlicensed (Part 18) industrial, scientific and medical (ISM) operators, the Wireless Communications Assn. (WCA) Fri. submitted a revised proposal to the FCC. The new document aims to “eliminate any legitimate concern from the microwave oven vendors,” which opposed the original WCA request to protect BRS licensees from interference due to ISM operations. ISMs now need “at least a week to formalize the position and response to the proposal,” said a spokeswoman for the Assn. of Home Appliance Manufacturers (AHAM), which represents microwave oven manufacturers.
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The FCC should resolve this matter before auctioning the 1710-1755/2110-2155 MHz bands for the advanced wireless service (AWS), WCA said. “BRS 1 is located at 2150-2156, which the FCC has reallocated for AWS,” WCA attorney Paul Sinderbrand said. The FCC ordered BRS channel 1 licensees’ relocation to 2496-2500 MHz to clear the way for AWS. “Unless the issues surrounding replacement spectrum for BRS 1 can be resolved before the auction, it will be difficult for an AWS auction to proceed because it will be unsettled as to whether there is appropriate replacement spectrum for BRS 1,” Sinderbrand said.
The FCC last year relocated BRS channel 1 operators to the 2496-2500 MHz band, suggesting, without technical support, BRS and ISM could co-exist. The agency imposed no power limit on ISM operators, prompting WCA to ask the FCC to assess and mitigate the potential for interference to BRS licensees from ISM operations. WCA asked the FCC to require all ISM devices marketed in the U.S. after Dec. 31, 2006, to restrict their emissions in the band to 500 microvolts/meter, measured at 3 meters -- the limit on unlicensed intentional radiators under Sec. 15.209(a) of the Commission rules. ISM interests opposed that request.
WCA now wants the FCC to restrict “ISM operations in the 2496-2500 MHz band to the maximum field strength levels currently set forth in Section 18.305 of the Commission’s rules for emissions above 2500 MHz.” Echoing its original proposal, WCA said it doesn’t want to impose the power limit on existing microwave emitters. “While the Part 18 limits currently apply below 2400 MHz and above 2500 MHz, under WCA’s proposal they would apply below 2400 MHz and above 2496 MHz after a transition period during which ISM interests could sell existing inventory and modify existing designs to meet the new rules,” WCA said.
“Our former proposal… would have subjected relocated BRS licensees to the same interference they face today at 2150-2156 MHz, but apparently would have required the ISM interests to lower their signals by too much,” Sinderbrand said: “Our new proposal will subject BRS licensees to greater interference [than] they face today, but based on the information we have, should not impose undue burdens on ISM. It will, however, require ISM to meet an in-band power limit for the first time.”
The WCA filing doesn’t include ISM industry contributions because ISMs didn’t submit “meaningful technical information regarding its emissions” in the band and refused to cooperate, WCA said. “WCA believes its new proposal is a reasonable compromise that is likely to accommodate the overwhelming majority of ISM devices with little, if any, changes required,” WCA said, adding it “hopes… the ISM community will now drop its shrill rhetoric and engage in a meaningful dialog to resolve the problem.” The AHAM spokeswoman said her group is “willing to have an open and transparent discussions. We are fully engaged and we have our policy and technical teams reviewing the proposal and formulating their responses.” - - Susan Polyakova