FCC Approves C-V2X Technology for Connected Vehicles Ahead of Final ITS Rules

On April 24, 2023, three Federal Communications Commission (FCC or Commission) bureaus — the Public Safety and Homeland Security Bureau, the Office of Engineering and Technology, and the Wireless Telecommunications Bureau — granted a joint request submitted by automotive manufacturers, equipment manufacturers, and state departments of transportation seeking a nationwide waiver of several FCC rules to permit deployment of cellular-vehicle-to-everything (C-V2X) technology in the upper 30 MHz of spectrum in the 5.895-5.925 GHz band.

Authorized by the 1998 Transportation Equity Act for the 21st Century,[1] the FCC has been working for nearly two decades[2] to develop a comprehensive national framework for intelligent transportation systems (ITS), manage finite spectrum resources, expand connected vehicle (CV) technology adoption and deployment, and position the United States to better compete in global markets.[3] After nearly 20 years of research, analysis, briefings, stakeholder engagements, and committee deliberations, the FCC issued its Order (the Order) granting the joint waiver[4] of 14 applicants to use C-V2X technology for safety-related applications in the 5.9 GHz band. C-V2X is an ITS technology that enables data sharing (or "communication") between vehicles, between vehicles and road infrastructure, and between vehicles and other road users. The Order comes ahead of final ITS rules and represents a significant step forward to hopeful stakeholders – the most optimistic of which see the Order as a signal that long-awaited regulatory certainty could finally be within reach.

Waivers filed by other ITS stakeholders remain pending while the FCC progresses towards adoption of final rules. As the FCC explains in its Order:

"To deny the joint waiver and insist on application of the current [dedicated short-range communication] DSRC-based rules would be contrary to the public interest as it would further entrench the [dedicated short range communication] technology the Commission determined needs to be replaced and preclude rapid deployment of the technology the Commission has identified as best suited to promote the most efficient and effective use of the spectrum."

Regulatory History of Spectrum Allocation for C-V2X

The FCC has taken prior actions to address efficiency and spectrum availability. On December 12, 2019, the FCC adopted an NPRM to consider comprehensive rules for the 5.9 GHz band, which proposed to make the band's lower 45 MHz available for unlicensed operations and permit C-V2X exclusive access to the upper 20 MHz. On November 20, 2020, the FCC announced its intention to offer waivers under 47 C.F.R. § 2.106, NG160[5] to ITS stakeholders to begin deployment of C-V2X technology in the 5.895-5.925 GHz spectrum band segment (referred to as the upper 5.9 GHz band) ahead of final ITS rules.

Following the announcement, the Commission's Public Safety and Homeland Security Bureau received numerous waiver requests for C-V2X deployment. Many applicants have already invested significant resources in innovative infrastructure to support C-V2X technology development. Others have emphasized the promise of expedited regulatory action to position the U.S. more competitively in global markets as other countries continue to prioritize C-V2X technological advancements.

In 2021, the FCC decreased the size of the ITS communication spectrum and made 1,200 MHz of spectrum in the 6 GHz band (5.925–7.125 GHz) available for unlicensed devices, including those that use Wi-Fi. The FCC is working with the U.S. Department of Transportation (USDOT) and the National Telecommunications and Information Administration (NTIA) to resolve outstanding issues before adopting final rules to allocate spectrum for ITS deployment, transitioning from dedicated short-range communication-based rules to allow for use of C-V2X technology.

Connected Vehicle Technology and Spectrum

Development of connected vehicle technology was made possible by both the FCC, which manages and sets rules for spectrum, and the USDOT, which manages and sets rules for vehicle and road safety, as well as stakeholders in the telecommunications and transportation industries. Using radio spectrum made available by the FCC, the USDOT and automotive manufacturers developed connected vehicle technology that allowed vehicles to communicate to avoid potential collisions.[6] Current reports continue to recognize interference-free access to spectrum as necessary for ensuring consistent operation and functioning for certain safety-related applications such as emergency braking, intersection management, lane change assist, and assisted collision warning.[7]

Connected Vehicle Technology. Collectively referred to as connected vehicle-to-everything (C-V2X), the technology includes vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-pedestrian (V2P) communications enabling vehicles, infrastructure, and other active road users to be in constant communication by leveraging existing cellular network infrastructure, including the latest fifth-generation technology standard for mobile wireless network operations (5G).[8]

However, in 1995, when the FCC allocated radio spectrum for transportation safety applications, C-V2X and 5G did not exist.[9] At the time, dedicated short-range communication (DSRC) was the only short-range communication method available.[10]

DSRC versus C-V2X. Similarities and differences between DSRC and C-V2X include:

• Dedicated Short-Range Communication (DSRC) is an earlier iteration of connected vehicle technology designed to enable V2V communication. DSRC uses communication devices located in vehicles (on-board unit, OBU), or connected to roadside infrastructure (roadside unit, RSU), that broadcast messages in the 5.9 GHz spectrum to other nearby units.

• Cellular Vehicle-to-Everything (C-V2X) builds upon the legacy technology to support communication in a more robust ecosystem of vehicles and infrastructure that use advanced cellular protocols like 5G. C-V2X is a newer technology for V2X communication that is cellular-based. "Cellular-based" means that C-V2X allows equipped vehicles and roadside devices to communicate through traditional cellular towers or directly without a tower, and the technology is designed to work with both 4G and 5G cellular technology.

Advantages of C-V2X include the ability to use LTE and to leverage existing cellular infrastructure to create a more comprehensive network and make concurrent transmissions, unlike DSRC that uses low latency and very low data volume. Consider, for example, a data-intensive use case like autonomous vehicles. DSRC is not well-suited to support autonomous vehicle operations due to the data packet size, and C-V2X is better suited to the type of high-volume data exchanges needed.

Spectrum. Spectrum refers to the invisible radio frequencies over which wireless signals travel.[11] Portions of spectrum are grouped into "bands" based on their wavelengths, and radio spectrum refers to radio frequencies used for communicating. The full spectrum ranges from 3 Hz to 300 EHz, and the portion used for wireless communication ranges from about 20 KHz to 300 GHz. 

Image Credit: NASA

Different types of spectrum are needed in different quantities for different areas, depending on the use case. This is because different spectrum bands have different properties, and a range of spectrum frequencies can be used for cellular communications:

• Low-band spectrum (under 3 GHz) travels longer distances with minimal signal interruption (e.g., wireless networks are built primarily on low-band spectrum).
• High-band spectrum (above 24 GHz) travels much shorter distances (e.g., meters, not miles) compared to low-band spectrum but offers higher capacity and ultra-fast speeds.
• Mid-band spectrum (between 3 and 24 GHz) provides a mix of coverage and capacity, blending characteristics of both low- and high-band spectrum.

Low frequency bands travel long distances, but low-band spectrum is in short supply and many bands are already heavily used. Higher frequency bands can be more readily accessible, but coverage performance issues remain despite capacity benefits.

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Next Steps: Anticipating Final ITS Rules

Remaining Issues. As the FCC continues to work with the USDOT and NTIA to establish final rules for ITS, remaining issues include the concerns of ITS stakeholders, which the National Transportation Safety Board (NTSB) saw as "three critical hurdles" to broad V2X deployment:

• Sufficiency of spectrum for advanced V2X applications,
• Potential for harmful interference from unlicensed devices, and
• Regulatory uncertainty.

The Order represents an important step in deploying C-V2X technology, but issues remain largely because current FCC rules are DSRC-based, and the C-V2X and DSRC standards are not compatible, which presents practical challenges that can only be addressed in the long-term by final rules.[12] For example, even if certain technical parameters were consistent with C-V2X operations, the current rules require use of DSRC technology and equipment. This means use of C-V2X roadside and onboard units would be an unauthorized operation under current rules.

Proposed Interim Solution. In the near term, the FCC has proposed a waiver process as an interim solution to bridge the gap and support C-V2X operations prior to adoption of final ITS rules. Recent waiver requests have reflected a variety of emerging technologies.

Regulatory Certainty. In the long term, only final rules carry the promise of regulatory certainty that will foster future C-V2X technology developments.

The DWT Mobility & Transportation Group is available to advise clients on these emerging issues as federal agencies continue to implement changes that impact ITS to ensure our clients are prepared to advance new technologies while responding to regulatory frameworks.

* On the date of this publication, Edlira Kuka was a law student at Seattle University School of Law and worked as a communications law, regulation & policy manager at DWT. On November 7, 2023, Edlira was admitted to practice law in the District of Columbia and became an attorney with DWT's Communications Practice.