The FCC will consider the 6 GHz band at its Oct. 23 open meeting—and a lot of people are excited about the prospects of more spectrum being unleashed for Wi-Fi and other unlicensed services. But the Ultra Wide Band Alliance holds “grave concerns” about the proposed power levels and the impact of using the entire 6 GHz band for new, unlicensed uses.
Representatives of the UWB Alliance met with FCC staff this past week to discuss the 6 GHz band and asked the FCC to consider mitigation solutions that will continue to allow for unlicensed UWB technologies to successfully coexist with incumbent users, according to an ex parte filing (PDF).
The alliance says numerous industrial and commercial applications that operate in the unlicensed 6 GHz band will be negatively affected should the band-sharing schemes some commenters are proposing be considered.
The UWB Alliance explained that while Wi-Fi is optimized for moving large amounts of data, UWB is optimized for bursts. Current regulations allow both UWB and wideband to coexist and that has resulted in UWB applications like smartphone ecosystems, consumer home automation, sports tracking and analytics and secure automated vehicle lock/unlock.
But the alliance argues there’s more to the story than what’s been reported by 6 GHz band proponents. The UWB Alliance and others, including AT&T, have performed their own initial evaluations of coexistence between current users of the 6 GHz band. “The results are not good,” the UWB Alliance said. “To date, there has been no thorough analysis performed to evaluate the threat to the UWB community, and the only study performed for licensed Fixed Service users by RFK Engineering Solutions is deeply flawed.”
In fact, the alliance asserts that the RFK study, which was commissioned by Radio Local Area Network (RLAN) proponents, is incomplete and lacking thorough evaluations of other users in the frequency band—and “the results are analogous to all the studies that showed smoking was not detrimental to respiratory health that were commissioned by the cigarette industry” in the 1960s.
Coexistence with other technologies is key, and the alliance proposes no mobile hot spots and significantly less power for all or some users. In the alternative, it wants to see IoT, including UWB devices, allowed to occupy both standard and low power designated portions of the band at the low power level and density specified in the FCC’s draft Notice of Proposed Rulemaking (NPRM).
As the FCC noted in the draft NPRM, the 6 GHz band is exclusive non-federal spectrum and is host to several incumbent services operating on a primary basis, including fixed point-to-point services, fixed-satellite service (FSS), broadcast auxiliary service and cable television relay service. A query of the FCC databases turned up 47,695 unique call signs between 5.925 and 7.125 GHz.
The UWB Alliance isn’t the only one registering concerns. The National Association of Broadcasters (NAB) met with FCC staff on Oct. 5 (PDF) and explained how broadcasters make extensive use of the U-NII-6 and U-NII-8 bands that are identified in the draft NPRM. The bands are used for electronic news gathering, including for portable transmitters on cameras that relay audio and video, as well as temporary fixed links to transmit program material back to studios.
NAB said that although it appreciates the efforts of the commission staff to address potential interference issues by proposing to confine unlicensed operations in the U-NII-6 and U-NII-8 bands to indoor operations, it has some concerns.
For one, confining unlicensed operations in these bands to indoor operations doesn’t address the potential for interference to broadcast operations that may take place indoors, such as at sports venues, political conventions or other events. For another, broadcast use for news gathering operations tend to have high “RF visibility” because the links travel over long distances, and these links can easily travel through residential neighborhoods where unlicensed operations near windows can cause interference.
NAB promises to submit its issues into the proceeding, but it’s suggesting that the commission might be more likely to gather a full record if the final NPRM were to directly ask whether unlicensed operations in the U-NII-6 and U-NII-8 bands should be confined to residential areas and how to effectively restrict those operations to residential areas.