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ARRL Asks FCC to Dismiss “Fatally Flawed” Petition for Rule Making Affecting 10 GHz


The ARRL has told the FCC that a Petition for Rule Making (RM-11715) from Mimosa Networks to permit unlicensed Part 15 wireless broadband services in the 10.0-10.5 GHz band is “fatally flawed” and should be dismissed. Mimosa filed the Petition in May 2013, and the FCC invited public comments last month. The Petition includes a band plan for 10.0 to 10.5 GHz that would cede Amateur Radio and Amateur-Satellite users access to just two small segments of the present allocation. The League told the FCC that, among other things, the Mimosa Petition is inconsistent with a US footnote in the domestic Table of Allocations, and that fact alone is sufficient reason for the Commission to quash Mimosa’s request.


“Footnote US128 very clearly and without equivocation prohibits all non-Federal services in the band 10-10.5 GHz except for the Amateur Service, the Amateur-Satellite Service, and the non-Federal radiolocation service,” the ARRL said in its comments. The FCC “is not at liberty to ignore” the US footnote, the League said, and is obliged on that basis alone to dismiss the Petition, “because it hasn’t the authority to grant it.”

Approval of the Mimosa Petition hinges on FCC adoption of rule changes that would put the 10 GHz band under Subpart Z of the Commission’s Part 90 rules. Subpart Z currently sets out regulations governing wireless licensing, technical standards, and operational standards in the 3650 to 3700 MHz band. Mimosa told the FCC that the “application of the coordination procedures and requirements provided in Subpart Z will ensure that Amateur Radio operations in the band will not be disrupted.”

Its suggested band plan, the company said, would protect frequencies in the band “that are most often used by Amateur Radio operators,” but the plan itself would carry no weight, since Mimosa fails to mention it among the rules changes it proposes. The plan would specify 10.350 to 10.370 GHz as an “Amateur Calling Band,” and 10.450 to 10.500 GHz for Amateur-Satellite operations in the midst of 21 wireless broadband channels and a small guard band.

[T]here is no ‘sharing’ between allocated radio services and Part 15 devices,” the ARRL said. “Part 15 unlicensed devices have no allocation status...and are prohibited from causing interference to any authorized radio service. That is not the regulatory paradigm proposed by Mimosa for the 10.0-10.5 GHz band.”

The League pointed out that Amateur Radio operations exist throughout the 10.0 to 10.5 GHz band now, and that Mimosa’s protocols for avoiding interference would not protect repeater input frequencies or interference to receivers used in “weak-signal” amateur operation. “Increases in the noise floor in this band that would result from wireless broadband operations as proposed would simply foreclose most or all amateur use of the band on an ongoing basis,” the ARRL asserted.

Even if the FCC could proceed with the proposed allocation, the League said, it would be “premature” to do so, because the US is now developing positions in advance of World Radiocommunication Conference 2015 (WRC-15). The League said WRC-15 agenda item 1.12 could have “a profound effect” on the 10.0-10.5 GHz band in ITU Region 2. “Action domestically on the Mimosa Petition now would foreclose certain options that the United States may wish to advocate at WRC-15, and the WRC-15 final acts may have an effect on this band as well,” the League explained.

The ARRL also pointed out that none of the channels in the Petition’s non-mandatory channelized band plan would be subject to out-of-channel emission limits. The League said that would effectively render the two Amateur Radio channels Mimosa proposes “subject to high noise levels, precluding operation in those segments for the uses now conducted in them.” The ARRL called the maximum EIRP “exceptionally high,” and noted that the Petition proposes no limitations on antenna configurations.

“Given this, and the impracticalities of the proposed non-interference requirement and the use of contention-based protocols as interference-limiting tools, it is quite obvious that Mimosa has propounded a seriously flawed proposal which fails to justify the allocation,” the League concluded. “The Petition should be dismissed without action by the Commission without delay.”




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