A myriad of stakeholders have offered the FCC advice on a notice of proposed rulemaking adopted in October that proposed to free up as much of 1,200 megahertz of spectrum for unlicensed use in the 6 gigahertz band (5.925-7.125 GHz band), with commercial, public safety, critical infrastructure, and scientific incumbents and prospective new entrants disagreeing on whether unlicensed operations can be permitted in the band without causing harmful interference to incumbents.
Incumbents say that if the FCC decides to permit unlicensed use of the band, it should adopt more stringent rules than those supported by unlicensed advocates. There is also disagreement about whether the Commission should permit any licensed use of the 6 GHz band.
“The proposed rules are designed to allow unlicensed devices to operate in the 6 GHz band without interfering with the operation of the licensed services that will continue to use this spectrum. In those portions of the 6 GHz band that are heavily used by point-to-point microwave links [5.925-6.425 GHz and 6.525-6.875 GHz], the Commission proposes to allow unlicensed devices to operate where permitted by an automated frequency coordination system and invites comment as to whether this is necessary for devices operated only indoors,” the agency said in a news release on the item, which was adopted in ET docket 18-295 and GN docket 17-183 (TR Daily, Oct. 23, 2018). “In the other portions of the band [6.425-6.525 GHz and 6.875-7.125 GHz] where licensed mobile services, such as the Broadcast Auxiliary Service and Cable Television Relay Service, operate, the unlicensed devices would be restricted to indoor operations at lower power. These proposed rules will allow a valuable spectrum resource to be more intensively used to benefit consumers while allowing the existing licensed uses of the 6 GHz band to continue uninterrupted.”
In 2017, the Commission adopted a notice of inquiry in its mid-band proceeding that included spectrum in the 3.7-4.2 GHz and 6 GHz bands (TR Daily, Aug. 3, 2017). A number of incumbents expressed concern in response to the NOI that use of the 6 GHz band by unlicensed devices would cause interference to their operations. Some reiterated those concerns in comments on the NPRM, while potential new entrants said the interference concerns were overblown.
In joint comments, Apple, Inc., Broadcom, Inc., Cisco Systems, Inc., Facebook, Inc., Google LLC, Hewlett Packard Enterprise, Intel Corp., Marvell Semiconductor, Inc., Microsoft Corp., Qualcomm, Inc., and Ruckus Networks said, “The Commission’s proposal to open the entire 6 GHz band for unlicensed technologies will expand access to broadband, promote innovation, and spur economic growth — while protecting existing users. The NPRM is a crucial step in making more unlicensed spectrum available to address exploding consumer demand for wireless technologies. The Commission has wisely proposed to make spectrum available under a regulatory structure based on the successful and time-tested Unlicensed National Information Infrastructure (U-NII) rules, while adding an additional set of conservative restrictions that will protect incumbent operations. These proposed rules accomplish this goal by creating different categories of unlicensed devices in four unlicensed 6 GHz sub-bands: 5.925-6.425GHz (U-NII-5); 6.425-6.525 GHz (U-NII-6); 6.525-6.875 GHz (U-NII-7); and 6.875-7.125 GHz (U-NII-8). In these comments, we explain how the Commission can adopt final rules for the band that promote efficient spectrum use, facilitate rapid deployment, and protect incumbent services from interference. Because access to this spectrum is so critical, both to meet growing consumer demand for Wi-Fi and to support other 5G investments, we ask that the Commission move quickly to resolve this proceeding and adopt rules that allow for rapid product deployment to maximize the value of the 6 GHz band for the country.”
The tech companies said that the FCC should “[i]mprove efficiency and intensity of use by permitting unlicensed operations to share the entire 5975-7125 MHz frequency range with incumbents — and reject introducing a new licensed mobile service in any portion of the band, which would displace incumbents.”
The Commission also should “[p]ermit standard-power AFC-controlled devices and LPI [low-power indoor] devices without AFC — while (1) allowing LPI devices to operate in all four sub-bands, (2) adding a 14-dBm very-low-power device class that can operate indoors or outdoors in U-NII-5, U-NII-7, and the bottom 100 megahertz of U-NII-8, (3) authorizing standard-power operations in U-NII-8 on a limited basis, and (4) revising proposed client-device power levels to permit symmetric operation,” according to the filing.
They also called on the FCC to “[a]dopt rigorous but flexible AFC rules that require careful protection of incumbents, while rejecting calls to over-regulate or dictate specific elements of AFC implementation, by permitting (1) portable and in-vehicle operation, (2) flexible geolocation strategies, (3) interference protection calculations that take FS and RLAN device height into account, and (4) operation without professional installation, device registration, ID transmission, or tracking of consumer devices or APs.”
The agency should also “[a]dopt technical rules based on the successful U-NII band, while also (1) adjusting power spectral density and client-device power levels to permit manufacturers to bring the latest wireless innovations to American consumers and (2) supporting WISPs’ efforts in rural communities by permitting greater directional gain for AFC-controlled devices and facilitating P2P and P2MP operations,” the companies added.
The Wi-Fi Alliance agreed “with the Commission’s proposal to divide the 6 GHz band into the U-NII-5 (5.925-6.425 GHz), U-NII-6 (6.425-6.525 GHz), U-NII-7 (6.525-6.875 GHz) and U-NII-8 (6.875-7.125 GHz) sub-bands, based on the characteristics of incumbent services.” It expressed support for regulating “unlicensed use in the 6 GHz band based on a ‘two-class approach,’ which differentiates between low-power, indoor-only (LPI) AP and standard-power AP devices.”
The alliance asked the agency to consider these “adjustments and clarifications” to the proposed rules: (1) “[a]llow LPI AP operations across the entire 6 GHz band, including the U-NII-5 and U-NII-7 bands, without an unnecessary automatic frequency coordination (‘AFC’) requirement for those bands”; (2) “[a]llow standard-power AP operations in U-NII-8 band using AFC technology to avoid transmissions in areas where TV pickup operations are licensed”; (3) “[a]llow client devices that operate under the control of an AP to operate at the same power level as the AP (whether standard-power or LPI)”; (4) “allow operation of fixed point-to-point operations with higher-gain antennas”; and (5) “allow mobile and transportable U-NII operations based on regulatory conditions comparable to LPI U-NII devices (i.e., applying very low power transmit power levels) or by using AFC technology.”
The Dynamic Spectrum Alliance said it “appreciates the Commission’s forward-thinking 6 GHz-band proposal and is eager to work with the Commission to ensure that dynamic spectrum access is a success in the band. The AFC approach the Commission proposes is only the most recent example of use of effective spectrum-sharing technologies to increase access to spectrum, and it is the result of hard work by Commission staff and a wide array of companies dedicated to making the most of the United States’ spectrum resources. DSA encourages the Commission to adopt its proposed framework, and to enact simple, flexible rules to support investment and innovation in the 6 GHz band.”
“The Commission should carefully craft technical rules to facilitate both incumbent and new unlicensed uses of the 6 GHz sub-bands. Protecting incumbents should remain the primary focus, but any new rules should, where possible, be harmonized with technical rules applicable to Unlicensed National Information Infrastructure (U-NII) devices that already operate in the 5 GHz band,” NCTA said.
NCTA said that the FCC should (1) “[p]ermit standard-power access points (APs) in the 5.925-6.425 GHz (U-NII-5) and 6.525-6.875 GHz (U-NII-7) sub-bands to use power levels permitted for unlicensed use in the U-NII-1 and U-NII-3 bands to operate on frequencies determined by an Automated Frequency Coordination (AFC) system;” and (2) “[p]ermit indoor, low-power AP operation in the 6.425-6.525 GHz (U-NII-6) and 6.875-7.125 GHz (U-NII-8) sub-bands using lower, more restricted power levels applicable to operations in the U-NII-2 band, so long as those operations do not cause harmful interference to incumbent users.”
NCTA also called on the Commission to (1) “[a]dopt higher permissible power limits for all client devices across the 6 GHz band;” and (2) “[p]ermit AP operations in the U-NII-5 and U-NII-7 bands under the same conditions as proposed for the U-NII-6 and U-NII-8 bands; i.e., low-power, indoor-only use without the need for authorization from an AFC system.” NCTA added that “[t]echnical analysis on the record suggests that these proposals can likely be adopted while still protecting incumbent operations. However, if additional technical analysis in the record suggests that incumbents would not in fact be protected from harmful interference, in either the near or long term, NCTA would no longer support the adoption of such rules.”
Starry, Inc., said that it “strongly supports the Commission’s quick action to make the 6 GHz band available for unlicensed operation, and largely supports the proposals in the 6 GHz NPRM. We believe that by allowing higher gain antennas and higher power client devices, along with deployment flexibility at any elevation, the Commission can ensure that this band will become part of the critical unlicensed backbone powering the U.S. wireless ecosystem, including for fixed wireless broadband.”
“The Commission should be commended for initiating this proceeding seeking comment on ways that 1200 megahertz of the 6 GHz band can be shared for unlicensed use. In particular, the Commission should make the U-NII-5 and U-NII-7 bands available at higher power to facilitate outdoor use under the control of the AFC and with the technical requirements described above,” said the Wireless Internet Service Providers Association. “With such rules in place, WISPs can take great strides to helping extend broadband access to more rural and unserved areas with less threat of harmful interference, and without causing interference to licensed links. The Commission also should adopt rules enabling lower-power indoor operations across the entire 6 GHz band.”
“As long as valuable incumbent uses are protected, unlicensed use in 6 GHz spectrum holds substantial promise to develop new services and enhance existing ones,” Verizon Communications, Inc., said. “Unlicensed versions of LTE (e.g., LAA, LTE-U, or newer versions) and WiFi will help expand capacity, relieve congestion on licensed wireless networks, and offer new broadband access points. To preserve a dynamic unlicensed ecosystem, any rules governing unlicensed operation in the band must maintain a technology-neutral approach that ensures permission-less innovation subject to compliance with all technical rules. The key to promoting unlicensed use in the 6 GHz band is a sharing model that protects incumbents through a cloud-based, IP-connected Automated Frequency Coordination (‘AFC’) manager. Unlike traditional unlicensed approaches that involve free-standing unmanaged devices, the AFC should use a ‘closed loop’ network framework that positively controls unlicensed radio access to the band and thereby protects incumbent operations. Active AFC management of unlicensed access points will enable greater security and protection and, in turn, allow for higher powered unlicensed use.”
“In principle we support the Commission’s approach to merge licensed and unlicensed services. If this can be successfully implemented, it will usher in a new, highly efficient, approach to frequency management. As expected, however, the devil is lurking in the details,” said the National Spectrum Management Association. “Given this new approach is unproven, we should proceed cautiously. A key component of the process will be the AFC function. The authorized agencies must meet the needs of all parties but be limited in number to avoid difficulty in determining the responsible agency for problem resolution. Another key component is a technical organization with extensive technical oversight and authority. An independent industry organization which is responsive to the needs of all interested parties should be used to develop the myriad of details needed to successfully implement these proposals. Among these would be the development of an appropriate path attenuation model adequate to protect licensed users. The organization’s responsibility should extend several years into the implementation phase. This organization should be allowed to develop technical details acceptable to operators and service providers and periodically report progress to the Commission.”
NSMA said that it “is one of a few organizations qualified to participate in this function. Field trials, monitored by all interested parties, should precede large scale implementation. The field trials should be based upon substantial agreement among all users. Large scale deployment should not begin until the field trials have been successfully completed to the substantial satisfaction of all parties.”
The 5G Automotive Association said it “supports the Commission’s efforts in these proceedings to identify new opportunities for unlicensed use in the 6 GHz band, and believes that the 6 GHz band – and not the 5.9 GHz band – represents the best opportunity for providing for more spectrum for unlicensed uses. However, without proper safeguards in place, out-of-band emissions (‘OOBE’) from secondary 6 GHz unlicensed operations will degrade primary licensed vehicle safety communications operations in the 5.9 GHz band. To prevent such an outcome, the Commission should adopt the protection criteria proposed by 5GAA herein.”
Motorola Solutions, Inc., said it “believes that the 6 GHz band has the potential to support a wide range of new and innovative applications. Therefore, MSI generally supports the Commission’s pursuit of a carefully crafted spectrum sharing approach that will accomplish the goal of expanded use of the 6 GHz band by secondary devices while providing sufficient protection for existing and future incumbent operations. As a critical component of this approach, MSI supports employing cloud-based AFC mechanisms that will allow rapid and uniform updates to incumbent protection information. MSI strongly believes that a carefully selected interference-to-noise (I/N) protection ratio is essential and recommends that the ratio for protecting critical incumbent links be set no higher than -12 dB I/N levels. Finally, the Commission should take several steps to enable the efficient and safe use of this band including by requiring AFC functions to record the operational frequencies and identifiers of authorized unlicensed devices operating in the band, and providing a mechanism for timely remediation of interference events.”
The Boeing Co. said it “supports the identification of additional spectrum resources in the 6 GHz band for [use] by unlicensed systems and devices. To ensure that this unlicensed spectrum is used for the greatest benefit, the Commission should refrain from imposing operating restrictions that are unnecessary to prevent harmful interference. Specifically, the Commission should permit all 6 GHz unlicensed devices to be used indoors without AFC control. The Commission should treat the inside of aircraft as indoor spaces for purposes of these rules and the Commission should permit the use of 6 GHz unlicensed spectrum for transmissions involving aircraft parked at airport facilities. Each of these measures will expand the use of unlicensed spectrum in the 6 GHz band without resulting in harmful interference to incumbent services. At the same time, the Commission should strive to ensure that the proposed additional unlicensed uses of the 6 GHz band do not prevent the continued operation of UWB devices that are also authorized in this spectrum.” Continue reading