Before the

Federal Communications Commission

Washington, DC 20554

In the Matter of )

)

Unlicensed Use of the 6 GHz Band ) ET Docket No. 18-295

)

Expanding Flexible Use in Mid-Band Spectrum ) GN Docket No. 17-183

Between 3.7 and 24 GHz )

To: The Commission

REPLY COMMENTS OF

THE PUBLIC INTEREST SPECTRUM COALITION

NEW AMERICA’S OPEN TECHNOLOGY INSTITUTE

PUBLIC KNOWLEDGE

AMERICAN LIBRARY ASSOCIATION

SCHOOLS, HEALTH & LIBRARIES BROADBAND (SHLB) COALITION

BENTON INSTITUTE FOR BROADBAND AND SOCIETY

CoSN – CONSORTIUM FOR SCHOOL NETWORKING

NATIONAL HISPANIC MEDIA COALITION

TRIBAL DIGITAL VILLAGE NETWORK

INSTITUTE FOR LOCAL SELF-RELIANCE

NEXT CENTURY CITIES

COMMON CAUSE

ACCESS HUMBOLDT

X-LAB

July 27, 2020

1

Table of Contents

I. Introduction and Summary 3

II. The Record Clearly Supports an Increased Power Level for Indoor-Only Devices 5

III. The Record Reflects Strong Support for Authorizing Client-to-Client Connections 10

IV. The Record Shows Strong Support for the Authorization of Very Low Power

Devices Across the Entire 6 GHz Band at Power Levels Up to at Least 14 dBm 12

V. The Record Supports the Authorization of Mobile Standard-Power Operations in

the 6 GHz Band 16

VI. The Commission Should Authorize the Use of Directional Antennas 18

VII. The Commission Should Not Impose a Preclusive Out-Of-Band Emissions

Restriction for the 5.9 GHz Band 18

VIII. Conclusion 21

2

Before the

Federal Communications Commission

Washington, DC 20554

In the Matter of )

)

Unlicensed Use of the 6 GHz Band ) ET Docket No. 18-295

)

Expanding Flexible Use in Mid-Band Spectrum ) GN Docket No. 17-183

Between 3.7 and 24 GHz )

To: The Commission

REPLY COMMENTS OF

THE PUBLIC INTEREST SPECTRUM COALITION

The Public Interest Spectrum Coalition (“PISC”) – comprising New America’s Open

Technology Institute, Public Knowledge, the American Library Association, the Schools, Health

& Libraries Broadband (SHLB) Coalition, National Hispanic Media Coalition, CoSN–

Consortium for School Networking, Benton Institute for Broadband and Society, Next Century

Cities, the Institute for Local Self-Reliance, Tribal Digital Village Network, Common Cause,

Access Humboldt and X-Lab – hereby submits Reply Comments in response to parties filing in

response to the Further Notice of Proposed Rulemaking (“FNPRM”) in the above-captioned

proceedings.1

1 Unlicensed Use of the 6 GHz Band; Expanding Flexible Use in Mid-Band Spectrum Between

3.7 and 24 GHz, Report and Order and Further Notice of Proposed Rulemaking, ET Docket No.

18-295 and GN Docket No. 17-183, FCC 20-51 (rel. Apr. 24, 2020) (“Report and Order” or

“FNPRM”). All citations to comments below were filed in this docket on June 29, 2020, unless

otherwise noted.

3

I. Introduction and Summary

In April, the Commission took a historic first step toward enabling the next generation of

Wi-Fi technology that will accelerate the availability and affordability of 5G-quality applications

and services to all Americans in every part of the country. With the right set of rules the

Commission can ensure the 6 GHz band is used to its fullest potential, creating both the world’s

most robust 5G wireless ecosystem and helping to bridge the digital divide. Accordingly, in these

reply comments, PISC describes how the record supports a number of additional provisions:

First, and most critically, the record reflects clear support for authorizing low-power,

indoor-only (LPI) devices at a power spectral density of 8 dBm/MHz across all 1200 megahertz

in the 6 GHz band. A wide variety of stakeholders joined PISC in observing that the technical

studies in the record clearly establish that a PSD limit of up to 8 dBm/MHz will not create a

substantial risk of harmful interference to incumbent operations. Authorizing LPI devices to

operate at this modestly higher power level across the entire 6 GHz band is necessary to ensure

that the public interest benefits of next generation Wi-Fi—including multi-gigabit capacity and

low-latency—is fully available and affordable in every home, business, school and library in the

country. Maintaining a PSD limit of 5 dBm/MHz will almost certainly deny the benefits of next

generation Wi-Fi to the typical home and small business.

Second, the record reflects support for the authorization of client-to-client connectivity.

Client devices should be allowed to intercommunicate when they are both within range of an

authorized 6 GHz access point. Doing so will unlock a wide range of important use cases for 6

GHz Wi-Fi, including for education, health care, industrial and mobile workforce use cases.

When clients are both sufficiently close to the access point, client-to-client connectivity is

4

extremely unlikely to cause harmful interference to incumbents, especially indoors, due to the

close proximity between the clients interconnecting for these sorts of applications.

Third, the record demonstrates overwhelming support for the Commission to authorize

the use of Very Low Power (VLP) devices across the entire 6 GHz band. However, merely

authorizing this new class of VLP devices is meaningless if the technical rules are not robust

enough to facilitate the potential innovation and consumer welfare possible in a 5G wireless

ecosystem. PISC urges the Commission to authorize a power level of 21 dBm EIRP – but in any

case a power limit no lower than 14 dBm EIRP (1 dBm/MHz power spectral density).

Fourth, the record shows strong support for the Commission to support mobile standard-

power operations. Authorizing mobile access points under the control of an AFC is no more

technically difficult than for fixed APs. Conceptually, the rules can parallel those the

Commission has proposed for TV white space devices (“WSDs”). The record supports an

authorization for mobile standard-power operations with an EIRP limit of 36 dBm.

Fifth, the record demonstrates strong support for the use of directional antennas. The

Commission should both permit and encourage AFCs to take account of antenna directionality in

order to make the most efficient use of this spectrum. The directional characteristics of antennas

can readily be incorporated into AFC calculations. Controlling the interference footprint of usage

can significantly increase the capacity of the band for both directional and non-directional users.

Finally, the Commission should reject proposals to increase the out-of-band emissions

(OOBE) limit at the bottom of the 6 GHz band. PISC strongly objects to any reconsideration of

this issue. The Commission considered and decided this matter in the Report and Order and did

not seek comment on a change. The auto industry’s proposal reinforces the need to relocate

future auto safety applications, particularly C-V2X, to another band such as the lightly-used 4.9

5

GHz public safety band. C-V2X should not be wedged between the current and future most

valuable and intensely used bands for high-capacity Wi-Fi. Relocating future auto safety

communications would achieve a win-win-win for broadband users, the automotive industry, and

5G mobile carriers.

II. The Record Clearly Supports an Increased Power Level for Indoor-Only Devices

The record shows strong support for increasing the power spectral density (PSD) limit for

LPI devices from 5 dBm/MHz to 8 dBm/MHz across all 1200 megahertz in the 6 GHz band. As

PISC stated in its Comments,2 a wide variety of stakeholders observed that the technical studies

in the record clearly establish that a PSD limit of up to 8 dBm/MHz will not create a substantial

risk of harmful interference to incumbent operations in the band.3 Authorizing LPI devices to

operate at this modestly higher power level is necessary to ensure that the public interest benefits

of next generation Wi-Fi—including multi-gigabit capacity and low-latency—is fully available

and affordable in every home, small business, school, and library in the country.4

Wi-Fi is the circulatory system for broadband connectivity in the United States and an

input into the productivity of virtually every other industry. The availability and affordability of

gigabit-fast Wi-Fi 6 connectivity is also essential to supporting high-speed internet connections

2 Comments of the Public Interest Spectrum Coalition at 14-15 (“Comments of PISC”). 3 See Comments of Dynamic Spectrum Alliance (“Comments of DSA”); Comments of NCTA—

The Internet & Television Association (“Comments of NCTA”); Comments of Microsoft

Corporation; Comments of Qualcomm Incorporated (“Comments of Qualcomm”); Comments of

Apple Inc., Broadcom Inc., Cisco Systems, Inc., Facebook, Inc., Google LLC, Hewlett Packard

Enterprise, Intel Corporation, Microsoft Corporation, NXP Semiconductors, Qualcomm

Incorporated, and Ruckus Networks, a Business Segment of CommScope (“Comments of RLAN

Group”); Comments of Wireless Broadband Alliance (“Comments of WBA”); Comments of Wi-

Fi Alliance. 4 Comments of Microsoft at 4-7; Comments of the Wi-Fi Alliance at 14-15; Comments of DSA

at 6-10; Comments of NCTA at 8-14; Comments of Qualcomm at 5-8; Comments of WBA at 7-

8; Comments of RLAN Group at 56-61.

6

in homes, schools, workplaces, and public spaces. This is particularly true indoors where more

than 80 percent of mobile device data is consumed. Wi-Fi offloads the vast majority mobile

network data traffic, a share that is expected to increase again substantially as consumers

transition to the higher-bandwidth applications and services that characterize 5G.

The high-tech industry coalition—Apple, Broadcom, Cisco, Facebook, Google, Hewlett

Packard Enterprise, Intel, Microsoft, NXP Semiconductors, Qualcomm, and Ruckus Networks—

are among the diverse range of parties that describe why this modest difference in PSD is so

important to end users: “The key differences between a 5 dBm/MHz and 8 dBm/MHz PSD limit

are (1) coverage area, (2) throughput in the covered area, and (3) a tendency to force traffic onto

the widest channels when narrower channels are sufficient.”5 According to technical findings

these companies put in the record, a PSD limit of 5 dBm/MHz would have serious adverse

consequences for households and small businesses in particular. They found that the lower PSD

limit reduces coverage range by 31-to-43% and throughput by 53-to-63%, on average.6 As a

result, “[u]nnecessarily limiting Wi-Fi coverage range means that users either cannot access Wi-

Fi in certain parts of their home, small office, or school, or that they must purchase, install, and

manage additional coverage extenders or access points.”7

For end users, the enormous social and economic benefits of Wi-Fi accrue

overwhelmingly to indoor use, especially at home. LPI connectivity will become the core value

proposition for next generation Wi-Fi only if the Commission chooses to authorize a functional

power level. PISC concurs with Microsoft’s prediction that LPI connectivity is much more likely

to be “deployed in residences and smaller businesses. Larger businesses and campuses which

5 Comments of RLAN Group at 57-58. 6 Ibid. 7 Ibid.

7

currently rely on some form of managed IT services, either internally or externally provided,

may want to utilize standard power access points and clients. At first, though, until one or more

AFCs are developed and certified by the Commission, all entities may have a need to operate

LPI devices.”8

Accordingly, PISC fully agrees with the Wi-Fi Alliance that “[s]ufficient PSD for LPI

devices is necessary to ensure that American consumers realize the full benefits of the 6 GHz

band.”9 The Wi-Fi Alliance correctly explains why a PSD below 8 dBm/MHz would deprive

consumers—and especially lower-income families—of the full benefits of next generation Wi-

Fi: “Power levels enable the enhanced throughput and capabilities of Wi-Fi 6 to reach beyond

one or two rooms without the need for signal extenders or additional equipment. In contrast,

reduced PSD below 8 dBm/MHz, will lead to two main problems for consumers and businesses

who rely on Wi-Fi. First, those consumers and businesses will experience a loss of coverage

area. In particular, 5 dBm/MHz reduces coverage range by 31-to-43%. Second, they will

experience reduction in throughput in the area that remains covered. A 5 dBm/MHz limit reduces

throughput by 53-to-63%.”10

PISC also strongly agrees with the Dynamic Spectrum Alliance (DSA), which explains

that a PSD limit of 5 dBm/MHz for LPI devices would undermine future Wi-Fi use cases if there

are “locations within a residence or business where an indoor client device may not be able to

successfully communicate with the indoor access point to close the link, let alone with the

minimum throughput necessary for a high-performance application. Either consumers must

accept that certain parts of their residence or business can’t be used for 6 GHz Wi-Fi or they will

8 Comments of Microsoft at 5. 9 Comments of the Wi-Fi Alliance at 14-15. 10 Ibid.

8

have to incur additional costs for purchasing and installing additional access points or extenders

to achieve the same WiFi performance that have come to expect today.”11

Some commenters argue that the threat of harmful interference is a reason for the

Commission to maintain a very restrictive low power for indoor use. However, as PISC and

other parties explained, the technical studies in the record establish that these fears are

misplaced. Most notably, the study submitted into the record by CableLabs clearly demonstrates

that a PSD limit of 8 dBm/MHz for LPI devices would not cause harmful interference to

incumbent operations in the 6 GHz band.12 In addition, in response to the FNPRM, CableLabs

filed the results of an additional technical study “that accounts for physical layer attributes of FS

links and looks at the impact to FS link SINR and link availability of introducing Wi-Fi

operating at a PSD of 8 dBm/MHz.”13 CableLabs specifically analyzed AT&T “Link 5,” which

the Commission found to be a more challenging case for LPI coexistence with incumbent fixed

links. This additional simulation demonstrated an “extremely low probability of FS SINR

dropping below the desired link level,” even when conservatively omitting variables regarding

FS operations that would further reduce the potential for harmful interference to FS from LPI

Wi-Fi at an 8 dBm/MHz PSD.14

As the Commission authorizes shared use to unlock unused spectrum capacity in

underutilized bands, incumbents predictably insist on absolute protection from even the most

remote chance of harmful interference. Even if 6 GHz incumbents had purchased exclusive

licenses at auction, rather than coordinating into this shared band at no cost, their claim that they

11 Comments of DSA at 7-8. 12 See CableLabs Dec. 20, 2019 Ex Parte; CableLabs Feb. 14, 2020 Ex Parte at 5-7; Comments

of DSA at 7-9; Comments of Microsoft at 6-7; Comments of RLAN Group at 59-61. 13 Comments of NCTA at 23-25. 14 Ibid.

9

must be spared even the most remote risk of interference from more productive use of the band is

misplaced. The Commission itself acknowledged this in the 6 GHz Report and Order, noting that

the agency “is not required to refrain from authorizing services or unlicensed operations

whenever there is any possibility of harmful interference. Indeed, such a prohibition would rule

out virtually all new services and unlicensed operations, given that there is virtually no type of

RF-emitting device that does not have the potential for causing such interference if used

incorrectly.”15

Broadband users and our economy would be deprived of the enormous benefits of new

wireless technologies, such as Wi-Fi 6, if incumbents are allowed to insist on virtually no risk

rather than on an appropriate policy balance that also recognizes—in the 6 GHz band in

particular—that incumbent fixed wireless operators and broadcasters do not have exclusive

licenses and never paid for use of the spectrum.

Further, the Commission has the authority and capacity to address any instances of actual

harmful interference that might arise.16 PISC concurs with NCTA on this point:

In the unlikely event that harmful interference did occur, the Commission’s

existing Part 15 rules provide a process through which a licensee can raise and

resolve the issue, . . . Such concerns are routinely resolved today under the

existing process. To the extent that incumbents experience harmful interference

from LPI unlicensed devices in the 6 GHz band, the rules are clear that the

operator must “cease operating the device upon notification by a Commission

representative that the device is causing harmful interference,” and may not

resume operations “until the condition causing the harmful interference has been

corrected.”17

15 Report and Order at ¶ 146; Comments of NCTA at 25-26. 16 Comments of Nokia at 4-5; Comments of the Utilities Technology Council, American Public

Power Association, National Rural Electric Cooperative Association, America Gas Association,

and American Water Works Association at 9-11; Comments of AT&T at 11; Comments of CTIA

at 6-7; Comments of the National Association of Broadcasters at 2-5. 17 Comments of NCTA at 26-27, citing 47 C.F.R. § 15.5(c).

10

III. The Record Reflects Strong Support for Authorizing Client-to-Client

Connections

The record reflects strong support for the authorization of client-to-client connectivity at

a sufficient power level to fuel the next-generation of connected devices such as immersive

technologies.18 Client devices should be allowed to intercommunicate when they are both within

range of an authorized 6 GHz access point. The record shows that doing so would unlock a wide

range of important use cases for 6 GHz Wi-Fi. When clients are both sufficiently close to the

access point, client-to-client connectivity is extremely unlikely to cause harmful interference to

incumbents, especially indoors, due to the close proximity between the clients interconnecting

for these sorts of devices and operations.

PISC agrees with Apple, Broadcom, Google, and Microsoft that client-to-client device

connections will be a practical necessity to realize the benefits of many important use cases for

LPI in particular. Prohibiting client-to-client communications would preclude a number of very

important and innovative use cases. This is notably the case for emerging digital education and

instructional applications that represent the next frontier of connected learning. The companies

note that the operations would “enable an instructor to stream high definition content directly to

students’ devices in a classroom setting and interact in real time. Such applications can

significantly benefit from a client-to-client topology so that they can be seamlessly deployed

without creating dependencies on a school’s installed AP infrastructure and without dramatically

increasing the traffic loads on that infrastructure.”19 End users should also be able to control, for

example, AR headsets from their smartphone while tethered to their home Wi-Fi router.

18 Comments of Qualcomm, Comments of Facebook, Comments of Apple, Broadcom, Google,

and Microsoft. 19 Comments of Apple, Broadcom, Google, and Microsoft at 11-12.

11

Further, client-to-client inter-communication will need to play a major role in enabling a

robust AR/VR landscape that could be enormously productive in industrial, healthcare and other

settings outside the home. Apple, Broadcom, Google and Microsoft note that if the Commission

were to adopt rules that requires “all traffic to be routed through fixed AP infrastructure

unnecessarily,” it would force “companies deploying AR/VR/MR applications to purchase not

only an AR/VR/MR solution, but also fixed APs compatible with that solution.”20 This would

inevitably slow innovation, raise prices, and reduce the utility of peripherals for both mobile

workers and other end uers. As the Wi-Fi Alliance notes: “There are multiple use cases that

require client-to-client indoor connectivity (e.g., screencasting, wearables, monitoring, etc.) and

the current rule already provides for a regulatory mechanism that can ensure that all client

devices remain in close proximity to indoor access points (i.e., indoors). Specifically, client

devices are enabled to detect access point transmission in order to initiate probe requests.”21

The record supports a presumption that the very nature of client-to-client communication

makes it extremely unlikely to increase the risk of actual harmful interference for incumbent

operations. As Qualcomm explains: “Authorizing client-to-client communications indoors also

would allow clients a few meters away from each other to directly communicate at lower

transmit power levels, lowering any interference risk and conserving precious device battery

resources, and, at the same, allow the serving AP to conserve power, lower system interference,

and improve spectral efficiency by not requiring the AP to carry the communications between

the two clients.”22

20 Id. at 12. 21 Comments of the Wi-Fi Alliance at 19-20. 22 Comments of Qualcomm at 7.

12

Even if the Commission remains concerned that a client device could move outdoors,

mitigation measures are feasible. Apple, Broadcom, Google, and Microsoft suggest that the

Commission could implement rules that authorize client devices using the 6 GHz band to

transmit data to a separate client device only if both devices receive a signal from a 6 GHz AP

enabling the transfer.23 In this scenario, if the client device receives an enabling signal, that

device would be allowed to transmit data using the same channel as the AP from which it

received that signal, and at the same power limit as a client device associated with that AP.24 As

the companies conclude: “Thus, two-way communications between client devices would only be

permissible if both clients receive such enabling signals or are associated with 6 GHz APs.”25

PISC concurs that this mitigation, if necessary at all, should be sufficient to ensure there is no

increased risk of harmful interference to incumbents.

IV. The Record Shows Strong Support for the Authorization of Very Low Power

Devices Across the Entire 6 GHz Band at Power Levels Up to at Least 14 dBm

The record reflects strong support among a diverse range of stakeholders for the

Commission’s proposal to authorize very low power (VLP) unlicensed devices to operate both

indoors and outdoors across the band’s entire 1200 megahertz unburdened by any requirement to

be under the control of an Automated Frequency Control (AFC) system.26 As PISC stated in our

Comments, it is crucial for VLP devices “to operate across all four 6 GHz sub-bands, both

23 Comments of Apple, Broadcom, Google, and Microsoft at 13-14. 24 Ibid. 25 Id. at 14. 26 See, e.g., Comments of the Consumer Technology Association at 5 (“Comments of CTA”);

Comments of the Wi-Fi Alliance at 3-9; Comments of DSA at 4-6; Comments of Wi-Fi Alliance;

Comments of Facebook; Comments of RLAN Group.

13

outdoors and indoors . . . [in order] to ensure that the next-generation of 5G- and Wi-Fi-powered

use cases are able to thrive and benefit consumers.”27

PISC agrees with the Consumer Technology Association (CTA) that authorizing the use

of VLP devices across the entire 6 GHz band “would enable many exciting new innovations that

are on the cusp of market entry,” including “immersive AR/VR technologies with wide-ranging

use cases” and “important peer-to-peer use cases.”28 Commenters describe a wide range of

potential use cases that include not just enhanced information, communication and

entertainment, but also enhanced health care and disability applications. Facebook describes how

AR technology “has the potential to revolutionize how medical patients are diagnosed (and

ultimately treated)” and can also “provide transformative benefits to those with hearing or vision

impairments.”29 The Wi-Fi Alliance similarly observes that VLP devices can help “healthcare

information technology managers [to] meet the growing connectivity demands presented by both

healthcare staff and patients and their families.”30

However, merely authorizing this new class of VLP devices is meaningless if the

technical rules are not robust enough to facilitate the potential innovation and consumer welfare

possible in a 5G wireless ecosystem. Recognizing this, a similarly broad and diverse range of

stakeholders propose that the Commission should authorize VLP devices to operate at power

levels up to no less than 14 dBm EIRP (1 dBm/MHz power spectral density).31 Absent

affirmative evidence of any probability of harmful interference to incumbent operations, the

27 Comments of PISC at 5. 28 Comments of CTA at 5-6. 29 Comments of Facebook at 3. 30 Comments of the Wi-Fi Alliance at 3-9. 31 See, e.g., CTA Comments at 6-7; Comments of the Wi-Fi Alliance at 9-13; Comments of DSA

at 4-6; Comments of Facebook at 3-6; Comments of RLAN Group at 10-32; Comments of

Qualcomm at 3-5; Comments of Microsoft at 2-3 and 7-8.

14

Commission should not consider adopting rules that limit the maximum allowed power to less

than 14 dBm for VLP devices in the 6 GHz band or jeopardize the future efficiency of this

spectrum band. PISC fully agrees with DSA that “[t]his very low power level combined with

factors such as body loss, itinerancy of VLP devices, and environmental clutter will allow the

small percentage of VLPs that are expected to actually operate outdoors at any given time to

share spectrum with incumbent services without causing harmful interference.”32

The record shows that a minimum power limit of 14 dBm is essential because body loss

is a significant source of attenuation for VLP devices.33 The high-tech industry coalition, for

example, demonstrates in a study by the Wireless Research Center that the total dynamic

position path loss between AR glasses and a user’s mobile handset in a 160 megahertz channel in

the 6 GHz band ranges from 26 to 96 dB.34 At the same time, a VLP device operating at 14 dBm

provides little risk of harmful interference to high-powered fixed links or other incumbents in the

band. As Facebook observes, a series of Monte Carlo simulations conducted by RKF

Engineering (the “RKF Report”), in conjunction with other technical analyses, “demonstrate that

VLP devices at power levels of at least 14 dBm EIRP will not cause harmful interference to 6

GHz licensed services.”35

32 Comments of DSA at 4. 33 See, e.g., Comments of Facebook at 4-6; Comments of Apple, Broadcom, Google and

Microsoft at 4-5; Comments of Wi-Fi Alliance at 11. See also Letter from Paul Margie, Counsel

to Apple Inc. et al. to Marlene Dortch, Secretary, FCC attachment at 5, ET Docket No. 18-295,

GN Docket No. 17-183 (Nov. 12, 2019); Letter from Paul Margie, Counsel to Apple Inc. et al. to

Marlene Dortch, Secretary, FCC at 1-2, attachment at 6, ET Docket No. 18-295, GN Docket No.

17-183 (Dec. 9, 2019). 34 See Comments of 6 USC, attachment B, Koichiro Takamizawa et al., On-Body Channel Model

and Interference Estimation at 5.9 GHz to 7.1 GHz Band, Wireless Research Center of N.C. at 1,

3 (June 2020) (the “Wireless Research Center Report”). 35 Comments of Facebook at 7, noting that the Commission has relied on Monte Carlo

simulations as a credible predictor in this proceeding. See 6 GHz Report and Order and FNPRM

at ¶ 127 (noting that “an approach based on Monte Carlo simulations would give a more reliable

prediction of the likelihood of interference”).

15

The United Kingdom’s regulator, Ofcom, reached this same conclusion. In its final order

released on July 24, Ofcom authorized VLP for use outdoors and indoors at a maximum power

of 25 mW (14 dBm) EIRP in the 5925-6425 MHz band. The agency also authorized LPI in the

band at a higher power level (250 mW).36 Ofcom conducted its own interference modeling,

based on Monte Carlo simulations, to support this outcome. Ofcom “undertook coexistence

analysis (see Annex 2) to understand the possible impact of future RLAN devices in the 6 GHz

(5925-6425 MHz) band on existing fixed links in the UK.”37 Ofcom stated that although it

"found from our modelling that there may be some scenarios where the fixed link interference

criteria could be exceeded, most likely from a single high-power device located either indoors or

outdoors close to the fixed link receiver,” it concluded that “these scenarios are very unlikely to

arise in practice for several reasons.”38 Among those reasons is the reality that both proximity

and line-of-sight transmission into an incumbent receiver would be rare: “Higher clutter losses

from buildings, trees and other obstacles in populated areas would further reduce the chances of

interference unless the RLAN was located very close to the fixed link receiver.”39

PISC groups are concerned that even 14 dBm may not be adequate to support the

innovations possible on portable devices with Wi-Fi 6 connectivity. Accordingly, PISC urges the

Commission to go further and consider authorizing VLP device use at power levels up to 21

dBm. As Apple, Broadcom, Google and Microsoft detail, this modestly higher power level

would allow “portable devices to communicate with an associated device at higher modulations,

and thus higher throughputs and lower latencies, keeping the distance between devices

36 Ofcom, Improving Spectrum Access for Wi-Fi: Spectrum Use in the 5 GHz and 6 GHz Bands,

Statement, at 1, 31 (rel. July 24, 2020), available at

https://www.ofcom.org.uk/__data/assets/pdf_file/0036/198927/6ghz-statement.pdf. 37 Id. at 15. 38 Ibid. 39 Id. at 16.

16

constant.”40 A higher limit would also permit “devices to maintain a minimum throughput or

latency level at farther distances or with additional clutter or attenuation.”41

V. The Record Supports the Authorization of Mobile Standard-Power Operations

in the 6 GHz Band

The record reflects strong support for the Commission to authorize mobile standard-

power operations with an EIRP limit of 36 dBm.42 PISC agrees with the high-tech industry

associations and other stakeholders that to optimize unlicensed use of the 6 GHz spectrum band,

the Commission should authorize standard-power access points for mobile applications under the

control of an AFC. Conceptually, there is no question that AFC’s are capable of calculating areas

that are safe for mobile access points under rules similar to those the Commission has proposed

for higher-power TV white space devices (WSDs) on mobile platforms.

PISC agree with Apple, Broadcom, Cisco, et al. that allowing mobile standard-power

APs to operate in the UNII-5 and U-NII-7 band segments “can unleash a wave of near term

innovation, from next-generation communications for commuters and students while in transit, to

vehicle-area networks that enable sophisticated data gathering and analysis, to providing

connectivity on demand in areas where deploying fixed APs may be impractical.”43 The

companies detail how authorizing mobile standard-power operations in the two bands would

promote next-generation connected services for internet access on public transit, unlicensed

mobile connectivity uses for the agriculture and construction industries, and mobile Wi-Fi mesh

40 Comments of Apple, Broadcom, Google, and Microsoft at 5. 41 Ibid. 42 Comments of the Wireless Broadband Alliance at 3; Comments of DSA at 10-19; Comments

of Microsoft at 12-16; Comments of the Wi-Fi Alliance at 15-17; Comments of RLAN Group at

32-56; Comments of ACT—The App Association at 7. 43 Comments of RLAN Group at 33.

17

systems for a wide range of uses such as mining, oil and gas, and other operations covering large

areas.44 Microsoft elaborates on how the higher EIRP level permitted for a standard power

access point can fuel mobile enterprise use cases such as “providing connectivity on campuses,

farms, construction sites, maritime ports, airfields, rail yards, and buses routes.”45

The record shows strong evidence that the Commission should not worry about harmful

interference from mobile standard-power operations due to the ability of an AFC to map

protection areas that ensure incumbents are as safe from interference as they would be vis-à-vis a

static AP. PISC agrees with the Dynamic Spectrum Alliance that “[a]n AFC system will ensure

that mobile standard power access points present a minimal risk of harmful interference to the

microwave fixed link receivers operating in the U-NII-5 and U-NII-7 bands.”46 PISC agrees with

Apple, Broadcom, Cisco, et al. that there is precedent for relying on a geolocation database:

The Commission has already authorized personal/portable white space device use

not only on frequencies allocated to broadcast television, but also on frequencies

allocated for public safety and other mobile licensed use based on the

Commission’s “high degree of confidence that the databases can reliably protect

[these] operations,” because “[p]ersonal/portable devices [that] rely on database

access to determine their list of available channels … can protect [incumbents] in

the same manner as fixed devices.”47

PISC also agrees with Microsoft that because “there are important technical and operational

differences between personal/portable WSDs and the services envisioned for mobile standard

power access points, only the relevant portions of the personal / portable WSD rules should be

considered.”48

44 Id. at 33-44. 45 Comments of Microsoft at 12. 46 Comments of DSA at 11-12. 47 Comments of 6 USC at 44-45. See Amendment of Part 15 of the Commission’s Rules for

Unlicensed Operations in the Television Bands, Repurposed 600 MHz Band, 600 MHz Guard

Bands and Duplex Gap, and Channel 37, Report & Order, 30 FCC Rcd. 9551 ¶ 88 (2015). 48 Comments of Microsoft at 13.

18

VI. The Commission Should Authorize the Use of Directional Antennas

The record reflects strong support for the use of directional antennas in the 6 GHz band.

PISC urges the Commission to both permit and encourage AFCs to take account of antenna

directionality in order to make the most efficient use of this spectrum. As the Dynamic Spectrum

Alliance opined: “Indeed, the Commission should not only permit directional antenna usage, the

regulations should encourage this use where possible. Controlling the interference footprint of

usage can significantly increase the capacity of the band for both directional and non-directional

users.”49

PISC broadly agrees with the Wireless Internet Service Providers Association (WISPA)

that the directional characteristics of antennas can readily be incorporated into AFC calculations:

The AFC should not treat all point-to-point or sector antennas as if they were

omnidirectional. That would be factually incorrect and spectrally inefficient and

could potentially preclude other point-to-point or even point-to-multipoint

operations from being approved by the AFC even thought there would be no

potential for harmful interference.50

VII. The Commission Should Not Impose a Preclusive Out-Of-Band Emissions

Restriction for the 5.9 GHz Band

The Commission should reject proposals to increase the out-of-band emissions (OOBE)

limit at the bottom of the 6 GHz band. 5GAA and Qualcomm contend that the Commission’s -27

dBm/MHz OOBE limit is insufficient.51 5GAA claims its “real-world testing” has shown that

“certain VLP unlicensed operations in and near a vehicle can cause harmful interference to C-

49 Comments of DSA at 21. 50 Comments of Wireless Internet Service Providers Association at 3. 51 Comments of 5GAA at 4-7; Comments of Qualcomm at 9-10.

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V2X Direct receivers,” and that the organization has shown the Commission these

demonstrations in the past.52

PISC strongly objects to any reconsideration of this issue in the context of the FNPRM.

The Commission did not seek comment on a change in the OOBE limit. It considered and

decided this matter in the Report and Order: “We believe that a limit of -27 dBm/MHz is

necessary to protect services outside the U-NII-5 and U-NII-8 bands, including the Intelligent

Transportation Service below the U-NII-5 band and federal government operations above the U-

NII-8 band.”53 5GAA presents no new evidence to suggest that the Commission’s conclusion

was incorrect, yet it goes even further to claim that “[c]ertain projections regarding the expected

proliferation of outdoor VLP unlicensed devices reinforce the danger of permitting these

unlicensed operations in the lower portions of the 6 GHz band” with no supporting citation or

proof to substantiate this claim.54

The FNPRM is not an appropriate venue for reconsideration. Moreover, the issue is

relevant for review, if at all, in the context of the Commission’s pending 5.9 GHz proceeding

that will decide what auto safety communications technologies, if any, to authorize for continued

operation in the top 30 megahertz of that band.

PISC urges the Commission not to undermine the historic progress it has made to enable

the future of Wi-Fi in both the 6 GHz band and the 5.9 GHz band central to the availability and

affordability of 5G-quality applications and services. The connected future of the country’s

homes, schools and small businesses should not be diminished due to unsubstantiated fears of

harmful interference that have already been investigated and addressed.

52 Comments of 5GAA at 4. 53 See Report and Order at ¶197. See 47 U.S.C § 15.407(b)(5) (effective July 27, 2020). 54 Comments of 5GAA at 6.

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Moreover, the arguments 5GAA and others make regarding potential interference to the

industry’s hypothetical auto safety service reinforces the rationale for moving at least Cellular

V2X operations out of the 5.9 GHz band entirely. As the Open Technology Institute, Public

Knowledge and other groups in PISC have argued previously, there is no reason future C-V2X

services need to be housed in the 5.9 GHz band other than an ill-fated decision 20 years ago to

require DSRC in the band.55 Today the ITS band is wedged between the current and future most

valuable and intensely used bands for high-capacity Wi-Fi: the UNII-3 band (5725-5850 MHz)

and the U-NII-5 band (5925-6425 MHz).

The 5GAA proposal suggests that C-V2X is being designed to be far more fragile and

susceptible to interference than DSRC is today. Rather than degrade the value of Wi-Fi in the

lower portion of the 6 GHz band, as 5GAA proposes, the Commission should look at other bands

that could offer C-V2X and other automotive communications operations more spectrum and

more insulation from intensively-used adjacent bands. The 4.9 GHz band, itself grossly

underutilized, could present an opportunity for the Commission to move these services as a win-

win-win for the automotive industry, the wireless industry, and for consumers. OTI and PK made

the case for this previously in comments,56 as has the Dynamic Spectrum Alliance.57 OTI

recently detailed this proposal in its recent paper: The 5.9 GHz Band: Removing the Roadblock to

Gigabit Wi-Fi.58

55 See Comments of New America’s Open Technology Institute and Public Knowledge, ET

Docket No. 19-138, RM-11771 (March 9, 2020). 56 Ibid. 57 Ex Parte Filing of the Dynamic Spectrum Alliance, Amendment of Part 90 of the

Commission’s Rules, WP Docket No. 07-100, ET Docket No. 19-138 (June 11, 2020) (the

Commission should “seek[] comment on relocating one or both of the [ITS] technologies

contemplated for the upper portion of the 5.9 GHz band to a portion (20 megahertz or more) of

the 4.9 GHz public safety band”). 58 Michael Calabrese and Amir Nasr, “The 5.9 GHz Band: Removing the Roadblock to Gigabit

Wi-Fi,” New America (July 9, 2020), https://www.newamerica.org/oti/reports/59-ghz-band/.

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VIII. Conclusion

The Commission should ensure that the rules governing the 6 GHz band promote the

most efficient and effective use of this spectrum. The record shows strong support for increasing

the power limit for LPI device operations in the 6 GHz band, for allowing client-to-client

communications, for authorizing a new category VLP devices across the entire band, as well as

mobile standard-power operations and directional antennas. All of these additional steps will be

necessary to achieve the robust, world-leading, and affordable 5G wireless ecosystem that the

Commission envisioned in its historic Report and Order.

Respectfully submitted,

NEW AMERICA’S OPEN TECHNOLOGY INSTITUTE

PUBLIC KNOWLEDGE

AMERICAN LIBRARY ASSOCIATION

SCHOOLS, HEALTH & LIBRARIES BROADBAND (SHLB) COALITION

BENTON INSTITUTE FOR BROADBAND AND SOCIETY

CoSN – CONSORTIUM FOR SCHOOL NETWORKING

NATIONAL HISPANIC MEDIA COALITION

TRIBAL DIGITAL VILLAGE NETWORK

INSTITUTE FOR LOCAL SELF-RELIANCE

NEXT CENTURY CITIES

COMMON CAUSE

ACCESS HUMBOLDT

X-LAB

/s/ Michael Calabrese

Amir Nasr

New America’s Open Technology Institute

740 15th Street NW, Suite 900

Washington, D.C. 20005

July 27, 2020