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US Technical Advisory Group 901 15th Street NW, Suite 520 ISO/TC 204 Intelligent Transport Systems Washington, DC 20005 Administrator: SAE International USA

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March 9, 2020

Ms. Marlene Dortch

Secretary, Federal Communications Commission

445 12th Street, SW

Washington, DC 20554

RE: ET Docket No. 19-138, Use of the 5.850-5.925 GHz Band

Dear Ms. Dortch:

The US Technical Advisory Group (US TAG) to the International Organization for Standardization

Technical Committee 204, Intelligent Transport Systems (ISO/TC 204), takes this opportunity to

comment in the above-referenced docket, regarding reallocation of the 5.850-5.925 GHz Band.

ISO/TC 204 is responsible for defining standards for the overall system and infrastructure aspects of

Intelligent Transport Systems (ITS) within ISO, as well as the coordination of the overall ISO work

program in this field, including the schedule for standards development, taking into account the work

of other existing international standardization bodies. The US Technical Advisory Group (US TAG)

to ISO/TC 204 is a group of experts in the transportation industry and is an American National

Standards Institute (ANSI) accredited body that is tasked with representing the views of US

stakeholders in ISO standardization activities.

US TAG experts have developed comments for this docket taking into account over two decades of

ITS development and deployment experience. The experts have concluded that there are serious

omissions and errors in the Commission’s proposal, errors and omissions that when corrected lead to

the inescapable conclusion that the proposed reallocation of ITS spectrum is ill-advised at best, and

is potentially harmful to the American public. Those comments, in opposition to the proposed rule,

are dated March 9, 2020 and are attached for the consideration of the Federal Communications

Commission.

Thank you for the opportunity to review and comment. If additional information is required, please

contact the US TAG Manager, Mr. Adrian Guan by phone (202) 336-9744 or via email

[email protected].

Respectfully submitted,

Koorosh Olyai, P.E.

US Expert and Chair, US TAG to ISO/TC 204

Andrew M. Schoka

US Expert, US TAG to ISO/TC 204

Barry Einsig


Bert Jakubs


mailto:[email protected]


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David Benevelli, P.E.


David Matta


Evgeny Klochikhin, Ph.D.


Faroog Ibrahim, Ph.D.


Greg Potter


Joseph Register


Kenneth Vaughn


Kevin Salzer


Michael A. Brown


Michael P. Onder


Mitch Tseng, Ph.D.


Paula Okunieff


Richard Roy, Ph.D.


Robert Rausch P.E.


Steve Sprouffske


Steven E. Shladover, Sc.D.


William J. Chundrlik, Jr


Wuping Xin, P.E. Ph.D.



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Before the

Federal Communications Commission

Washington, D.C. 20554

In the Matter of )

)

Use of the 5.850-5.925 GHz Band ) ET Docket No. 19-138

)

Comments of the US Technical Advisory Group to

ISO Technical Committee on Intelligent Transport Systems

March 9, 2020

1 Introduction

ISO Technical Committee 204 (ISO/TC 204) is responsible for defining international standards for the overall

system aspects and infrastructure aspects of Intelligent Transport Systems (ITS), as well as the coordination of

the overall ISO work program in this field including the schedule for standards development, taking into

account the work of existing international standardization bodies. The US Technical Advisory Group (US

TAG) to ISO/TC 204 is a group of experts in the transportation industry and is an American National

Standards Institute (ANSI) accredited body that is tasked with representing the views of US stakeholders in

the ISO processes.

ISO/TC 204 primarily deals with standardization of information, communication and control systems in the

field of urban and rural surface transportation, including intermodal and multimodal aspects thereof, traveler

information, traffic management, public transport, commercial transport, emergency services advanced driver

assistance and driving automation systems, and commercial services in the ITS field. One of its key goals is to

develop and standardize ITS services that promote safety and efficiency in the transportation sector through

sharing of information, and this includes standards and services that utilize the 75 MHz of 5.9 GHz spectrum

set aside in many countries for deploying safety-of-life-and-property services involving V2X

communications.

The content of this response is the position of the signatories to the document as members of the US TAG and

US Experts to ISO/TC 204.

2 Executive Summary

In its NPRM, the FCC has proposed to reallocate the 5.850-5.895 GHz spectrum currently allocated to ITS for

use by unlicensed devices. The FCC further proposes to allow ITS services to retain their co-primary

allocation in the upper 30 MHz band segment (5.895-5.925 GHz) of the 5.9 GHz Band. In accordance with

the FCC charter which obligates the Commission to allocate spectrum to maximize benefit to the American

public, the US TAG’s consensus is that the public benefit of preserving and protecting from interference the


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entire 75 MHz for transportation safety, efficiency and mobility, exclusive of unlicensed operation,

substantially exceeds that of re-purposing the lower 45 MHz of the 5.9 GHz ITS band for unlicensed use. A

summary of the benefits to the public is shown in the table below.

Comparison of Estimated Public Benefits for alternative uses of Spectrum [1], [14]

Public Benefit Categories Unlicensed operations Dedicated ITS Spectrum Economic Welfare $82.2 – 189.9 billion >$940 billion

Annual Reduction in Fatalities - 1,321

Annual Reduction in Crashes - 594,000 Annual Reduction in Traffic

Delays - 280 million hours

Annual Climate Benefits - 400,000 tons of CO2

As such, the US TAG believes that allocating only 30 MHz for V2X safety and efficiency is neither sufficient,

nor in the public interest and demonstrates an error in judgment on the part of the Commission. We therefore

strongly urge the Commission to reverse its decision and instead preserve the availability of the currently

allocated ITS spectrum, the entire 75 MHz in the 5.9 GHz band, and ensure its availability for current and

future transportation safety applications.

3 Financial Benefits of Preserving the Full 75 MHz of the 5.9 GHz ITS Band for V2X Safety

and Efficiency and Connected Automation

In the NPRM, the Commission seeks comments on the following:

o “the benefits and costs of designating a significant portion of this band for unlicensed operations”

[para 65]

o “whether estimating the contribution to GDP of increases in Wi-Fi throughput is an appropriate way

to measure the benefits of introducing unlicensed operations in the 5.9 GHz band” [para 65]

There are a number of similar requests for comments in the NPRM concerning the costs versus the economic

and social benefits of reallocating 45 MHz of ITS spectrum to unlicensed operation without seeking comment

on the benefits of keeping the entire spectrum for ITS. Indeed, the Commission states “our goal in the

proceeding is to revise the current 5.9 GHz band plan to optimize the efficient and effective use of the band by

making the band available both for unlicensed use and ITS services.”[para 63] and also seeks comment on

“the transportation and vehicular-safety related applications that are particularly suited for the 5.9 GHz band

[ref. 5.895-5.925GHz only] as compared to other spectrum bands, and how various bands can be used

efficiently and effectively to provide these applications.”[para 19] The US TAG contends that not seeking

information on whether the reallocation of 45 MHz is in the best interest of the public in the first place is a

significant oversight by the Commission. In order to address this oversight, we answer the following

question: do the economic and societal benefits of retaining the current allocation for ITS outweigh the

benefits of reallocating 45 MHz to unlicensed service? And our answer is they do by a substantial amount.

The fact that in the NPRM the Commission has not done a thorough economic and social benefits analysis of

retaining the entire 75 MHz for ITS safety and efficiency services represents a significant error in judgment.

Estimates of the economic benefits associated with revoking the lower 45 MHz of the 5.9 GHz ITS band in

favor of unlicensed use are documented in a 2018 RAND study [1]. According to that study, “…the total gains

to economic welfare in the form of consumer and producer surplus range from $82.2 billion to $189.9

billion.” Those numbers are based on the full 75 MHz being re-allocated while only 45 MHz is proposed for

re-allocation in the NPRM, but more importantly, those economic gains are grossly inflated because the


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RAND study does not account for the economic benefit from the proposed 1.2 GHz of spectrum for

unlicensed devices above 6 GHz (FCC Docket 18-295). In contrast, the US Department of Transportation has

estimated the combined annual economic benefit of using the full 75 MHz of the 5.9 GHz ITS band for V2X

technologies at over $940 billion annually when considering the impacts of reductions in the loss of life,

injuries, other quality of life factors and traffic congestion [2].

The RAND study also shows that less than 10% of wireless internet traffic occurs “on the go”; therefore, the

bandwidth demands of individual users are substantially constrained by the necessary range of service because

the vast majority of wireless internet traffic is indoor use. Furthermore, the RAND study asserts that “…the

economic contribution from public Wi-Fi (e.g., “free” Wi-Fi) is relatively small” and that “from a practical

measurement perspective, residential access is also reflective of the true value that consumers get from Wi-Fi,

since it is the access they most directly pay for (via their monthly internet plan).” However, the proposed

unlicensed emissions rules for the U-NII-4 band (up to 36 dBm EIRP) and prior filings from cable operators

in FCC Docket 13-49 clearly show that one of the goals of the NPRM is to enable what essentially amounts to

an outdoor replacement for cellular services that traditionally operate in licensed bands for which taxpayers

have been reimbursed through auctions. Considering the disparity between the comparative economic

benefits, the true demands of wireless internet as evidenced by the RAND study, and the rules proposed in the

NPRM, the re-allocation of the lower 45 MHz of the 5.9 GHz ITS band would clearly constitute an arbitrary

and capricious decision that compromises the safety and efficiency of the US transportation system.

Even more startling in comparison to the RAND study is the $4 trillion automation benefit estimated by

former Corporate Vice President of Research and Development for General Motors, Lawrence Burns, based

on research performed at Columbia University [3,4]. Connected cars will substantially improve the wealth and

health of individual Americans by further enabling vehicle automation and reducing transportation-related

emissions. The FCC’s basis for the proposed rulemaking versus the economic and quality of life

improvements made possible by mitigating millions of vehicular crashes and reducing the corresponding

injuries and fatalities, reducing congestion and enabling cooperative driving automation, constitutes a

significant error in judgment. Twenty-two state and local-level government agencies expressed their support

for and the importance of preserving the 5.9 GHz ITS band in a January 23, 2018 letter to the US Department

of Transportation and the FCC [5], and all fifty States, Puerto Rico and the District of Columbia are

represented in the August 19, 2019 AASHTO letter to the FCC advocating for continued reservation of the

ITS spectrum [6]. The US TAG strongly urges the FCC to reverse its decision and not adopt the proposed

rulemaking.

4 ITS Needs 75 MHz for Safety and Efficiency Services

In the NPRM, the Commission seeks comments on the following:

o “propos[al] to dedicate 30 megahertz of spectrum in the upper portion of the 5.9 GHz band at 5.895-

5.925 GHz to support ITS operations in this band” [para 20]

There are a number of similar requests for comments in the NPRM concerning the best use of the remaining

30 MHz of ITS spectrum to support ITS safety services without considering the fact that that 30 MHz is

insufficient to do so. Indeed, the Commission states “In re-examining the best use of the 5.9 GHz band, we

seek to ensure the most efficient and effective use of this valuable spectrum resource and believe that ITS

users can be accommodated in a significantly smaller spectrum space considering the recent and anticipated

future technological developments relating to transportation and vehicular safety-related applications.”[para

20] This statement is a clear indication that the Commission did not study whether 30 MHz was sufficient

spectrum for achieving the maximum benefit to the public, rather stated it was their “belief” that it was. This

represents a serious error in judgment by the Commission. In order to address this oversight, we answer the

following question: What is the amount of 5.9GHz spectrum that is necessary to deploy the suite of ITS

safety and efficiency services that maximize the benefit to the public? And the answer is 75 MHz; 30 MHz is


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not sufficient.

The US TAG strongly advocates that the full 75 MHz of ITS spectrum be retained for interference-free V2X

communication. In order to maximize the benefits to the public, the system must have sufficient capacity and

it must be protected from harmful interference.

V2X services address four main categories of societal benefit [7]:

1) Safety

2) Transportation Efficiency

3) Cooperative Automation

4) Environmental Protection

The industry-consensus standard SAE J2945 [8] provides a clear channel usage plan that illustrates how the

various channels in the band are used to support services in these categories. It is important to note that safety

and efficiency related communications occur throughout the 75 MHz of ITS spectrum.

Safety-related services appropriately receive the most attention. There are more than 100 fatalities, 9,000

injuries, and18,000 crashes per day on our roadways [15]. The U.S. Department of Transportation has

estimated that V2X can prevent or mitigate approximately 80% of crashes involving unimpaired drivers. [27].

Dissemination of Basic Safety Messages (BSMs) [9] enables a large set of V2V collision avoidance

applications. In many typical road environments, BSMs require on the order of 15%-20% of the 75 MHz ITS

spectrum [13]. Indeed, it is only through the employment of active channel congestion controls that BSMs can

be prevented from saturating that resource. The BSM is not the only V2V safety message. For example,

Emergency Vehicle Alert and Collective Perception Service messages also improve safety through V2V

communication, and are sent using spectrum resources that do not conflict with BSMs to avoid exacerbating

the BSM congestion issue. Likewise, cooperative driving automation applications, with further potential for

improving traffic safety and efficiency, will require other parts of the ITS spectrum.

In total, the USDOT’s Architecture Reference for Cooperative and Intelligent Transportation (ARC-

IT, http://www.arc-it.org) identifies 30 safety-related service packages that entail either V2V or I2V

communications, including:

- Intersection Safety Warning and Collision Avoidance

- Curve Speed Warning

- Stop Sign Gap Assist

- Road Weather Motorist Alert and Warning

- Reduced Speed Zone Warning / Lane Closure

- Work Zone Safety Monitoring

- Pedestrian and Cyclist Safety

- Situational Awareness (e.g., warnings about objects in the roadway)

- Emergency Vehicle (Signal) Pre-emption

- Queue Warning

While each of these applications has an individually modest spectrum requirement, they all represent

extremely important high-impact messages that require immediate availability of spectrum resources to

prevent loss of life and property. Critically, all these safety services require local information processing and

low-latency information distribution with extremely high availability; requirements that cannot be met using

cellular communications. The system must to be configured such that the spectrum resources required for

these services are available when they are needed. Interference from lower priority services or other sources

can not be tolerated. Once these services are in place, the benefits to the public include estimated annual

reductions in fatalities by 1,321 and crashes by 594,000 [1,14]!

http://www.arc-it.org/


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A third dimension of safety communication will originate in personal devices to protect vulnerable road users

(VRUs) like pedestrians, bicyclists, and road workers. Growth in injuries and fatalities for VRUs is a

particularly troubling phenomenon. [26] Pedestrian fatalities have increased by 50% since 2009; and the

technology to prevent many of these fatalities exists today and only requires sufficient spectrum. [Source:

https://www.ghsa.org/resources/Pedestrians19]

The Personal Safety Message [10] is the primary means for VRUs to directly alert vehicles of their presence

and movement, and is expected to play an important role in improving safe road use. In many urban areas,

there will be high densities of both vehicles and VRUs. Consequently, the current plan [8] envisions sending

BSMs and PSMs in non-overlapping spectrum. Any reallocation of the 75 MHz of ITS spectrum will result in

BSMs and PSMs having to use overlapping spectrum, degrading the performance of personal safety services

at a time when pedestrian fatalities are increasing [26].

The ITS community, including national, state, and local departments of transportation, are committed to

improving traffic efficiency and reducing the environmental impact of transportation. To that end, a large

number of applications have already been researched and are in preparation for deployment. It is important to

note that these deployment decisions depend on assurance that the ITS spectrum will remain available to

support the applications which include [11,12]:

- Intelligent Traffic Signal System (I-SIG)

- Transit Signal Priority (TSP)

- Freight Signal Priority (FSP)

- Mobile Accessible Pedestrian Signal System (PED-SIG)

- Dynamic Speed Harmonization (SPD-HARM)

- Queue Warning (Q-WARN)

- Cooperative Adaptive Cruise Control (CACC)

- Automated platooning, especially for heavy trucks

- Response, Emergency, Staging, and Communications. Uniform Management, and Evacuation

(RESCUME)

- Intelligent Network Flow Optimization (INFLO)

- Connection Protection (T-CONNECT)

- Dynamic Transit Operations (T-DISP)

https://www.ghsa.org/resources/Pedestrians19


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- Dynamic Ridesharing (D-RIDE)

- Freight Advanced Traveler Information System (FRATIS)

- Freight-specific Dynamic Travel Planning and Performance

- Drayage Optimization (DR-OPT)

- Commercial Vehicle Moving Inspection

- Eco-Approach and Departure at Signalized Intersections

- Eco-Traffic Signal Timing

- Eco-Traffic Signal Priority

- Connected Eco-Driving

- Eco-Cooperative Adaptive Cruise Control

- Eco-Lanes Management

- Eco-Speed Harmonization

While subsets of these services can be delivered using wide-area-wireless technologies (e.g. cellular), most

have communication requirements that best fulfilled through low latency, free access to dedicated ITS

spectrum for short range communication. As with I2V safety, the bandwidth requirements of individual

applications are not always high, however in aggregate they are significant. The benefits of such services

include estimated annual reductions in traffic delays by 280 million hours and CO2 emissions by 400,000

tons! [1,14]

Connected and Automated Vehicles (CAVs) (aka Cooperative Automated Driving Systems (cf. SAE J3216

[43])) are the fastest growing V2X application area. Automated driving is a key strategic initiative in the

United States transportation community. Automated driving requires a vehicle to have a rich and accurate

understanding of the map where it is driving, of its location on the map, and of the dynamic location and

movement of other road users. On-board sensors like radar, cameras, and lidar provide data to build those

dynamic map and location models. Research has already demonstrated the efficacy of sharing data among

vehicles and roadside devices to augment the data provided by on-board sensors. Standardization efforts are

nearing completion on a Collective Perception Service which will allow such sharing between vehicles, and

the spectrum requirements for such a valuable service are similar to those for the BSM. Furthermore, there

will be similar spectrum requirements for communication among automated vehicles (at various levels of

automation) to ensure the safety of the public on the roads. A recent C2C-CC study [13] analyzing the

spectrum requirements of these three main safety and efficiency services concludes that 30 MHz is

insufficient and that around twice that amount is necessary to achieve the safety and efficiency benefits

desired. Finally, it is worth mentioning that the USDOT is actively working with ISO TC 204 and the US

TAG to extend ARC-IT to support emerging service packages, such as those for automated vehicles (ISO

24318), integrated mobility (ISO 4447), and curbside management (ISO 4448). It is expected that these efforts

will result in dozens of additional services requiring V2V and I2V communications.

Absent a full spectrum-enabled V2X rollout, the U.S. continues to lose almost 40,000 lives per year on U.S.

roads. A USDOT report [14] made the following observations on the benefits of V2X:

• Crash population targeted by V2X safety applications at intersections includes up to 575,000 crashes

(involving more than 5,100 fatalities) annually

• Crash population targeted by V2I safety applications at curves includes up to 169,000 crashes

(including 5,000 fatal crashes) annually

• Reduction of crashes by up to 25% during winter weather due to weather traffic management

applications on freeways

• Reduction in speed variations between freeway segments by 18%-58% and within freeway segments

by 10%-47%, resulting in fewer rear-end crashes

• Fewer instances of hard braking and up to 89% reduction in maximum deceleration in incident zones

Repeatedly-validated studies show V2X technology can prevent up to 80% of all traffic accidents, 594

thousand crashes and save up to 1,321 lives every year [1,14] Drivers can well relate to the need for V2X


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messaging helping them in the following time-critical application scenarios:

• Intersection assist. Alerts the driver of a potential collision with another vehicle traveling on a cross-

street that is likely to run a red light or stop sign. T-bone accidents are often fatal. Radar systems are

unable to provide sufficient warning, and network latency using other communications technology

could render this application ineffective.

• Left-turn assist. Alerts the driver if there's not enough time to make a left-hand turn because of

oncoming vehicles. This application can keep the driver from turning even when the oncoming car is

out-of-sight. Radar systems are unable to provide this benefit.

• Forward-collision warning. If the vehicle detects that the driver is traveling at such a speed that it

will hit a slower-moving or stopped vehicle (even one the driver cannot yet see), it provides a

warning. Other communications technologies can complement this application, but they cannot

provide the real-time, localized and non-line-of-sight (NLOS) performance of V2X.

• Do-not-pass warning. On 2&3-lane roads, the vehicle warns the driver if there is a vehicle coming in

the opposite direction making it unsafe to pass a slower-moving vehicle. Other technologies do not

provide the performance guarantees this application requires.

• Blind-spot/lane-change warning. Provides a warning when another car is positioned in the driver’s

blind spot in an adjacent lane. The application can also warn the driver if they activate the turn signal

when it's unsafe to change lanes. V2X provides capabilities not achieved by existing blind-spot

monitoring systems (e.g., radars, cameras) in that it provides kinematic information that the driver

needs to be aware of to make a proper response.

• Advance warning of a vehicle braking ahead. The vehicle gives the driver an alert when another

vehicle up ahead, likely out of sight, hits the brakes. This can help prevent a rear-end collision in

NLOS scenarios typified by urban driving and driving in poor visibility weather conditions. Other

technologies, including radar, do not provide the performance guarantees this application requires.

The above services are non-exhaustive and are based solely on use of the Basic Safety Message. In concert

with other real-time messages such as signal phase and timing (SPaT), local topology, and a variety of other

real-time Vehicle-to-Infrastructure (V2I) messages, many other safety services – including pedestrian safety –

can be implemented. Example V2I/I2V messages enabling infrastructure-supported safety include:

• Signal Phase and Timing (SPaT) and associated MAP topology messages – SPaT enables real-time

indication of intersection state, red light warning and other services that non-real-time

communications can not deliver.

• Traveler Information Messages (TIM) alert roadway users in real-time of road state, work zones,

upcoming curves, etc.

• Signal Request Messages (SRM) and associated Signal Status Messages (SSM) that allow emergency

services and railroads to securely preempt traffic signal controllers without a wired network

connection

New services will be built on these existing messages, and ultimately new messages and services will be

developed to further increase the safety and efficiency of surface transportation. As discussed in the previous

section, successful implementation all these valuable services will require the entire 75 MHz of ITS spectrum

currently allocated. If the proposed rulemaking is adopted, these facts make it clear that, to the extent they

can be deployed at all, ITS safety and efficiency services will not be capable of delivering anything close to

the maximum benefit that the public expects and the FCC is supposed to provide.

Finally, as the US Department of Transportation noted, in October 2018 [28] there were already more than 70

active DSRC deployments, using all seven channels and with thousands of vehicles on the road, including the

large number of ITS safety and efficiency services deployed today in the Connected Vehicle Pilot programs in

New York City, Tampa, FL, Wyoming, and Columbus, Ohio [29]. Had the original NHTSA NPRM [27]

mandating V2V deployments in vehicles starting in 2019 been adopted, these deployments would have been

much farther along. In a recent study, the University of Michigan Transportation Research Institute estimated


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that delays of three to seven years for V2V (Vehicle-to-Vehicle) deployments result in 7.4 million to 19.1

million additional crashes, and up to 105,746 lives lost throughout the United States.[30], which gives some

idea of the cost to the public as a consequence of the delays promoted by the proponents of this NPRM.

5 Out-Of-Band-Emissions

Making no concession regarding our immutable position in favor of continuing to allocate the entire 75 MHz

spectrum (5.850-5.925 GHz) for ITS, we are also compelled to comment on the serious interference problems

that will exist for the safety-critical ITS applications should the Commission open a U-NII-4 band. In the

NPRM, the Commission states “We propose that U-NII-4 devices, or devices that operate across a single

channel that spans the U-NII-3 and U-NII-4 bands, meet an OOBE limit of -27 dBm/MHz at or above 5.925

GHz” [para 54], and seeks comment on:

• “the OOBE limits we should apply at the upper end of the U-NII-4 band and whether any spectrum

must be reserved to protect ITS services,96 and if so, whether such spectrum should be in the U-NII

or ITS segment of the 5.9 GHz band.”[para 54]

Asking what OOBE limits should be applied without making any proposal that there be any such limits is a

clear admission by the Commission that they have not properly considered the effects of unlicensed emissions

on the 30 MHz they propose to leave for ITS services. This demonstrates a serious lack of expertise on the

part of the Commission. We address this oversight noting our position that the entire 75 MHz of spectrum be

retained for ITS safety and efficiency services.

An obligation of Part 15 U-NII operation is to create no harmful interference to licensed operations (Rule CFR

47 §15.5 (b)). A key aspect of that protection comes from limiting out-of-band emissions from U-NII devices

into adjacent licensed bands. The Commission has consistently adopted an OOBE limit of -27 dBm/MHz at

the edge of all 5 GHz U-NII bands (U-NII-1, U-NII-2A, and U-NII-2C, with U-NII-3 as the sole

exception)[15], and has also proposed that all U-NII 5/6/7/8 OOBE be limited to -27 dBm/MHz below 5.925

GHz [16]. The Commission’s decision to significantly deviate from the -27 dBm/MHz standard in the U-NII-

3 case prompted strong objections from the ITS community in 2016 [17]. The current NPRM presents

questions about an OOBE limit for the proposed U-NII-4 band

The promise of a U-NII-4 band has always been to provide “full protection” for ITS operating above U-NII-4

[18]. However, that commitment has never been backed up with an OOBE limit proposal that would ensure

compliance with Rule CFR 47 §15.5 (b). Failure to provide adequate protection for licensed ITS and an

insistence that proposed rules are adequate despite evidence to the contrary represent significant errors in

judgment. More recently, Wi-Fi advocates and Commission members have advocated for higher and higher

interference allowances, while blithely asserting that lifesaving ITS services would be protected. The NPRM

takes this to an extreme by asking whether OOBE limits are even needed, i.e. asking “should the Commission

also establish a separate limit at the upper U-NII-4 band edge (i.e., at 5.895 GHz)?” [19, paragraph 24]. Of

course OOBE limits are needed at the U-NII-4 band edge and throughout the 5.895-5.925 GHz portion of the

ITS band, and they must be sufficient to ensure conformance to Rule CFR 47 §15.5 (b). The Commission’s

only OOBE proposal is for a limit at 5.925 GHz, i.e. above the ITS band. The Commission does not propose

any OOBE limit in the range 5.895-5.925 GHz. This indicates that the Commission is more concerned about

protecting non-ITS incumbents operating above 5.925 GHz, than about protecting licensed ITS incumbents

operating below 5.925 GHz. We find this to be arbitrary and it is of great technical concern to the technical

experts of the US TAG. While promoting the development of unlicensed services is admirable, and a clear

priority for the Commission, it is contrary to the public interest to prioritize unlicensed services so heavily that

the life-saving ITS services for which the ITS band is allocated cannot reliably function. Unlicensed services


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are secondary to licensed services and are generally allowed only to the extent they do not interfere with any

licensed services, especially those in adjacent bands.

Evidence of harmful interference from U-NII-4 operations into ITS operations in the 5.895-5.925 GHz band is

already available; this is not a mere theoretical concern. Tests have amply demonstrated the reality of this

harmful interference, and neither the Commission nor commenters should make claims about protecting ITS

services without proof. The Commission’s own “Phase 1” test report [20] investigated the problem of

unmitigated U-NII-4 operations interfering with ITS communication in 5.895-5.925 GHz. For example,

Figure 11 of that report clearly demonstrates the reality that such interference exists when prototype U-NII-4

devices transmit. As a commenter noted at the time [21, pp. 3-4]

“Figure 11 shows the impact on packet completion rate for DSRC occurring on Channel 180, Channel

182, and Channel 184 with a U-NII device operating simultaneously at Channel 177. The figure

indicates that DSRC operations at Channel 180 are impacted once the U-NII device’s signal power

reaches -60 dBm and then falls precipitously until there is a 0% packet completion rate by -48 dBm.

The implication is that the signal of a U-NII-4 device operating with the proposed maximum transmit

power of +36 dBm Equivalent Isotropically Radiated Power (EIRP) could experience 96 dB of

attenuation and still drown out critical DSRC transmissions. Assuming a free-space propagation

mode, 96 dB of attenuation is roughly equivalent to an interference range of 250 meters or more. In

other words, if high power outdoor U-NII-4 Wi-Fi devices are permitted to operate under the ‘re-

channelization’ approach, there could be a permanent interference zone of at least 250 meters around

such devices. Considering that a preferred location for such high power outdoor Wi-Fi devices would

often be near an intersection or along a street, the test results reveal that the critical DSRC collision

avoidance benefits expected in those same areas would likely be permanently lost.”

The above referenced commenter also provides a similar analysis for the evident interference ranges

impacting channels 182 and 184. While the test cited above was for the rechannelization proposal [22], U-NII-

4 operation under this NPRM would equally lack any mitigation for ITS in 5.895-5.925 GHz, so the same

exact conclusion holds.

Evidence of harmful U-NII-4 interference is also found in reports published by the U.S. Department of

Transportation (USDOT). One such report [23] measures the impact of interference from an IEEE Std.

802.11ac device operating in the proposed U-NII-4 band on DSRC vehicle-to-vehicle communication. The

V2V communication was only 75 meters and line-of-sight, for which the packet error ratio (PER) is shown to

be negligible in the absence of interference. However, when the IEEE 802.11ac device is operating in 20, 40,

80 or 160 MHz channels, the PER spikes as high as 91%, to levels that would “endanger the function” of ITS

safety services, i.e. would by definition [24] constitute harmful interference. Elevated PERs are seen across

the entire 5.895-5.925 GHz band, and are expected to be even higher for critical V2V distances above 75 m

and/or for non-line-of-sight V2V scenarios. The report concludes, “Cross-channel test results showed the

potential for cross-channel interference, having an impact on DSRC performance, up to [an interference]

range of 500 meters or more, but typically between 200 and 300 meters.” [23]

Finally, we note that under existing regulations, ITS devices are themselves strictly constrained in their out-of-

channel emissions. For example, the Class C transmit spectral mask requires a 10 MHz transmission to be

attenuated by 50 dB at 10 MHz above the channel edge [25]. For a typical 10 dBm/MHz transmission, this

equates to an out-of-channel power spectral density level of -40 dBm/MHz. It would be illogical to apply a

looser constraint to unlicensed devices than is applied to a licensed device.

We strongly urge the Commission to revisit its rules and proposals related to harmful interference to safety-of-

life ITS operations emanating from all U-NII bands, including from U-NII-4 if it is opened. These include

rules for OOBE, for maximum transmit power, and for potential indoor-only operation. The Commission

should consider existing test data and develop new test data where appropriate. The Commission should also


12

note that the highest risk for harmful interference to ITS comes from U-NII devices operating in, on, or

adjacent to ITS vehicles, road users, and infrastructure, especially at power levels that are more than an order

of magnitude above standard ITS levels (36 dBm compared to approximately 20 dBm). If the Commission

wishes to avoid having its rules challenged before other federal branches, the final rules must be consistent

with Rule CFR 47 §15.5 (b), ensuring that ITS safety services are protected from harmful interference.

6 Conclusion

The FCC charter obligates the Commission to allocate spectrum to maximize benefit to the American public.

The US TAG has presented sufficient evidence and has achieved consensus that the public benefit of

preserving and protecting from interference the entire 75 MHz for ITS safety and efficiency substantially

exceeds that of re-purposing the lower 45 MHz of the 5.9 GHz ITS band for unlicensed use. Furthermore, the

US TAG believes that allocating only 30 MHz for ITS safety and efficiency is neither sufficient, nor in the

public interest. We therefore strongly urge the Commission to withdraw its proposed rulemaking and instead

preserve the availability of the currently allocated ITS spectrum, the entire 75 MHz in the 5.9 GHz band, and

ensure its availability for current and future transportation safety and efficiency applications.

References:

[1] The Potential Economic Value of Unlicensed Spectrum in the 5.9 GHz Frequency Band,

Insights for Future Spectrum Allocation Policy, RAND Corporation, 2018.

https://www.rand.org/pubs/research_reports/RR2720.html

[2] Letter from Secretary Elaine L. Chao to FCC Chairman Ajit Pai Re: Draft Notice of Proposed Rulemaking

In the Matter of Use of the 5.85 – 5.925 GHz Band, US Department of Transportation, November 20, 2019.

[3] Autonomy: The Quest to Build the Driverless Car – and How It Will Reshape Our World, Lawrence D.

Burns with Christopher Shulgan, HarperCollins Publishers, 2018.

[4] TRANSFORMING PERSONAL MOBILITY, Lawrence D. Burns, Director, Program on Sustainable

Mobility; William C. Jordan, President, Jordan Analytics LLC; Bonnie A. Scarborough, Program Manager,

Program on Sustainable Mobility; The Earth Institute, Columbia University, August 10, 2012.

[5] Letter from COALITION FOR SAFETY SOONER to Secretary of Transportation Elaine L. Chao, Office

of Management and Budget Director Mick Mulvaney, and FCC Chairman Ajit Pai, January 23, 2018.

[6] Letter from the American Association of State Highway and Transportation Officials (AASHTO) to FCC

Chairman Ajit Pai, August 19, 2019.

[7] https://www.its.dot.gov/pilots/cv_pilot_apps.htm

[8] SAE J2945: Dedicated Short Range Communication (DSRC) Systems Engineering Process Guidance for

J2945/x Documents and Common Design Concept

[9] SAE J2945/1: On Board System Requirements for V2V Safety Communications

[10] SAE J2945/9: Vulnerable Road User Safety Message Minimum Performance Requirements

[11] https://www.its.dot.gov/pilots/pilots_mobility.htm

https://www.rand.org/pubs/research_reports/RR2720.html

https://www.its.dot.gov/pilots/cv_pilot_apps.htm

https://www.its.dot.gov/pilots/pilots_mobility.htm


13

[12] https://www.its.dot.gov/pilots/pilots_environment.htm

[13] https://www.car-2-

car.org/fileadmin/documents/General_Documents/C2CCC_TR_2050_Spectrum_Needs.pdf

[14] https://rosap.ntl.bts.gov/view/dot/3569

[15] CFR 47 §15.407 General Technical Requirements

[16] In the matter of Unlicensed Use of the 6 GHz Band, FCC Notice of Proposed Rulemaking, ET Docket

18-295, October 24, 2018.

[17] Petition for Reconsideration, ET Docket No. 13-49, Association of Global Automakers, Inc., and Alliance

of Automobile Manufacturers, May 6, 2016.

[18] Comments of Qualcomm Incorporated, ET Docket No. 13-49, Qualcomm, Inc., May 28, 2013.

[19] Use of the 5.850-5.925 GHz Band, FCC Notice of Proposed Rulemaking, December 17, 2019.

[20] PHASE I TESTING OF PROTOTYPE U-NII-4 DEVICES, Report: TR 17-1006, FCC OET, October 22,

2018.

[21] Comments of Toyota Motor Corporation, In the matter of Phase I Testing of Trototype U-NII-4 Devices,

ET Docket 13-49, November 28, 2018.

[22] The Commission Seeks to Update and Refresh the Record in the “Unlicensed National Information

Infrastructure (U-NI) Devices in the 5 GHz Band” Proceeding, FCC 16-68 Public Notice, June 1, 2016.

[23] DSRC and Wi-Fi Baseline Cross-channel Interference Test and Measurement Report, Vehicle-to-Vehicle

Communications Research Project, U.S. Department of Transportation and CAMP Vehicle Safety

Communications 6 consortium, December 2019.

[24] CFR 47 §15.3 (m) Definition of harmful interference.

[25] Standard Specification for Telecommunications and Information Exchange Between Roadside and

Vehicle Systems – 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control

(MAC) and Physical Layer (PHY) Specifications, ASTM International E2213-03, September 2003

[26] 2018 Fatal Motor Vehicle Crashes: Overview, U.S. Department of Transportation National Highway

Traffic Safety Administration, October 2019,

https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812826

[27] https://one.nhtsa.gov/About-NHTSA/Press-Releases/ci.nhtsa_v2v_proposed_rule_12132016.print

[28] “Preparing for the Future of Transportation: Automated Vehicles 3.0 (AV 3.0)”, U.S. Department of

Transportation, October 2018, https://www.transportation.gov/av/3/preparing-future-transportation-

automated-vehicles-3

[29] CV Pilot Deployments:

https://www.its.dot.gov/research_archives/safety/cv_safetypilot.htm

https://www.tampacvpilot.com/learn/resources/

https://www.its.dot.gov/pilots/pilots_environment.htm

https://www.car-2-car.org/fileadmin/documents/General_Documents/C2CCC_TR_2050_Spectrum_Needs.pdf

https://www.car-2-car.org/fileadmin/documents/General_Documents/C2CCC_TR_2050_Spectrum_Needs.pdf

https://rosap.ntl.bts.gov/view/dot/3569

https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812826

https://one.nhtsa.gov/About-NHTSA/Press-Releases/ci.nhtsa_v2v_proposed_rule_12132016.print

https://www.transportation.gov/av/3/preparing-future-transportation-automated-vehicles-3

https://www.transportation.gov/av/3/preparing-future-transportation-automated-vehicles-3

https://www.its.dot.gov/research_archives/safety/cv_safetypilot.htm

https://urldefense.proofpoint.com/v2/url?u=https-3A__www.tampacvpilot.com_learn_resources_&d=DwQFAg&c=pqcuzKEN_84c78MOSc5_fw&r=z8R-nWJ8GIxwjOjNKhEFByb-tZ6XE3GZXWSggNdVo-w&m=98HemWglgu3Uas86g8E5dyN3PQxE1UeB-BayaARBcOo&s=n8CT9zigLtDJlf2ls0Tiz4dnNGZD-O221EJJtQ_0-Bo&e=


14

https://www.its.dot.gov/pilots/pilots_nycdot.htm

https://wydotcvp.wyoroad.info/

https://smart.columbus.gov/uploadedFiles/Projects/Smart%20Columbus%20Concept%20of%20Opera

tions-%20Connected%20Vehicle%20Environment.pdf

[30] Sayer, James R., Carol A.C. Flannagan, and Andrew J. Leslie, The Cost in Fatalities, Injuries and Crashes

Associated with Waiting to Deploy Vehicle-to-Vehicle Communication, University of Michigan

Transportation Research Institute, Ann Arbor, MI

https://urldefense.proofpoint.com/v2/url?u=https-3A__www.its.dot.gov_pilots_pilots-5Fnycdot.htm&d=DwQFAg&c=pqcuzKEN_84c78MOSc5_fw&r=z8R-nWJ8GIxwjOjNKhEFByb-tZ6XE3GZXWSggNdVo-w&m=98HemWglgu3Uas86g8E5dyN3PQxE1UeB-BayaARBcOo&s=q0LvkLl1saFkJVjWwtjwdALDPf1t-UkNZoL40-Sz1c4&e=

https://urldefense.proofpoint.com/v2/url?u=https-3A__wydotcvp.wyoroad.info_&d=DwQFAg&c=pqcuzKEN_84c78MOSc5_fw&r=z8R-nWJ8GIxwjOjNKhEFByb-tZ6XE3GZXWSggNdVo-w&m=98HemWglgu3Uas86g8E5dyN3PQxE1UeB-BayaARBcOo&s=CQBVC9OH6N-KYSpnSX9Wun_rjvkyGJrGeqsUYPzac5k&e=

https://smart.columbus.gov/uploadedFiles/Projects/Smart%20Columbus%20Concept%20of%20Operations-%20Connected%20Vehicle%20Environment.pdf

https://smart.columbus.gov/uploadedFiles/Projects/Smart%20Columbus%20Concept%20of%20Operations-%20Connected%20Vehicle%20Environment.pdf

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