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NAB Warns FCC About 6 GHz Interference with ENG

Broadcasters are asking the FCC to make sure it protects incumbent newsgathering operations in the 6 GHz midband spectrum it is eyeing for unlicensed use. 

The FCC voted unanimously in October 2018 to propose opening up the 1,200 MHz of that midband spectrum for unlicensed use, including WiFi. It is under pressure from Congress to open up more midband, considered the sweet spot for broadband. The FCC has yet to vote on an order so stakeholders continue to weigh in.

Broadcasters use the 6 GHz band for auxiliary (BAS) operations--"sporting events, breaking news and special events" and says the FCC's proposed interference protections--limiting it to lower-power, indoor operations--miss the mark, particularly since some camera transmitters used to relay footage back to stations also operate indoors and at low power, so they would be in the interference line of fire even with those limitations on unlicensed devices.

One reason the 6 GHz spectrum is so attractive is that it lies between the current unlicensed bands and the potential unlicensed spectrum being freed up in the C-band. 

NAB argues the computer companies, both Microsoft and others in the WiFi Alliance, "assume away" the challenges of protecting those BAS operations. 

In a filing with the FCC Dec. 5, the National Association of Broadcasters said that despite the suggestions by some (see below), that WiFi devices can be used across the band with little of no impact on incumbents, "experience and common sense" suggest otherwise. 

Related: NAB, Wi-Fi Alliance Battle Over 6 GHz 

NAB said that the two sub-bands allocated for mobile primary use should not face " uncoordinated unlicensed operations, whether indoors or outdoors."   

Broadcasters point out that electronic newsgathering (ENG) is often operating indoors and in close proximity of potentially to thousands or even tens of thousands of WiFi hotspot, "which makes such coordination impractical and unworkable." 

NAB said it is willing to work on coordinate sharing of ENG, but said such systems are "a critical component to public warning, newsgathering and content generation." 

NAB pointed out ENG has already lost access to three ENG channels at 2.5 GHz "due in large part to interference from 2.4 GHz WiFi Systems." It says that based on that broadcasters are sure that they face interference to 6 GHz ENG systems from uncoordinated use, even limited to indoor locations.  

NAB is facing some stiff competition for the spectrum. 

In a meeting with FCC chair Ajit Pai last month, Microsoft chairman Brad Smith urged the FCC to free up the entire 6 GHz band for low-power unlicensed indoor operations--like WiFi.  

Broadband operators represented by NCTA-the Internet & Television Association, are obviously on the same page given the importance of WiFi hot spots to mobile "fixed" service. They also want the FCC to free up all 1,200 MHz of the spectrum for unlicensed, while protecting incumbent users like newsgathering. 

Meanwhile, CTIA, which represents wireless carriers using licensed spectrum, has asked the FCC to make the upper portion of the 6 GHz band available for licensed, flexible use, or at least seek comment on that proposal, saying the FCC's current trajectory is skewed toward unlicensed. That trajectory is at least one point on which broadcasters would agree.