Motorola, Public Safety Clash on 4.9 GHz Standard
Motorola and the National Public Safety Telecom Council (NPSTC) clashed at the FCC last week over deployment of 4.9 GHz spectrum and the “mask” needed to minimize interference, as some public safety groups move toward deployment of this newly created band. Sources said once that critical issue is resolved they expect an FCC decision within 2 months.
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The key question before the FCC is at which power levels one of 2 masks will apply. Motorola and NPSTC agree that at lower levels a relatively lenient mask, 802.11a, will suffice. The fight is over when to apply the more restrictive DRSC mask, based on a mask designed for an intelligent transportation system band. NPSTC said the tougher mask should apply at power levels of 20 dBm and above. Motorola said the cutoff should be at 8 dBm, and that’s the central disagreement at the FCC.
NPSTC sent the FCC results of a simulation it ran, which it said showed little need for the more restrictive mask for more transmissions. NPSTC said as FCC reviews the results “it will be apparent that the selection of a standard emission mask… over a more stringent mask (e.g. DSRC Mask C) has little if any effect upon real life user operations,” the group said. NPSTC added, “It will not provide any significant performance gains, and will in fact stifle the technological innovation and economic gains that would be otherwise available by properly aligning public safety’s requirements with technologies developed for larger markets.”
Steven Devine, a communications official in Mo. and chmn. of the NPSTC Spectrum Management Committee, told us that if the stricter mask is required many public safety agencies that have applied for 4.9 GHz licenses won’t take advantage of the spectrum. With the tighter mask “manufacturers would have to redo their dies and refit their product lines and we don’t feel that the public safety market is big enough for that,” Devine said.
Devine also charged that the conversion costs could run $5 million per vendor and limit the number that would offer 4.9 GHz equipment. “We'd like to benefit from 10 or 20 manufacturers making products,” he said. “To those of us in public safety we feel that’s important.”
Motorola disputed the public safety arguments in its own ex parte filing at the FCC last week. Motorola said the FCC should exercise care to assure it doesn’t create the 800 MHz interference scenario -- recently addressed by the FCC its 800 MHz rebanding order, which was the product of years of negotiations. “Many users will be finding a way to use this spectrum in a variety of scenarios,” a Motorola official said Mon.: “We ought to build a little more margin into the technical specifications to help reduce the risk of interference.”
Motorola also disputed claims that the use of the tighter mask would keep come vendors from competing in the space. Motorola maintains that to meet the standard would require a minimum of equipment adjustments -- which it estimated would cost dollars per unit: “Meeting mask is a $3 cost business decision, not a barrier to entry,” Motorola said in a filing.
The FCC adopted licensing and service rules for the band in an April 2003 order that allocated 50 MHz for wireless broadband public safety use. A year ago, NPSTC asked the Commission to reconsider the order, saying most of the rules were in line with the needs of public safety but some parts needed to be retuned, including an “unnecessarily restrictive emission mask” and the lack of interoperability standards.