U.S. FCC adopts new ITS rules to govern C-V2X deployment in the 5.9 GHz band

Below we highlight key elements of the Final Rule.

C-V2X standards

Contrary to the approach taken with DSRC, the FCC did not mandate a particular technical standard for C-V2X. The FCC considered incorporating into its rules either 3GPP Release 14 or Release 16, but instead chose to defer to industry’s determination. The Commission encouraged industry to develop a consensus concerning the appropriate technology standard for C-V2X moving forward, aligning with the technical requirements prescribed in the Order. The FCC also emphasized its commitment to safety and the importance of interoperability as technical standards evolve in the future, with backwards and forward compatibility, regardless of manufacturer or vehicle integrator. Finally, invoking ongoing regulatory actions specific to connected vehicles at the U.S. Department of Transportation and the U.S. Department of Commerce Bureau of Industry and Security, the FCC cautioned equipment manufacturers implementing C-V2X to comply with existing privacy and cybersecurity best practices.

Band Usage

The existing ITS rules include a hierarchical system for messages that prioritizes safety communications. The FCC sought comment on whether to maintain the hierarchy used for DSRC and whether to limit the 5.895-5.925 GHz band to non-commercial services or safety-of-life applications. After reviewing stakeholder comments, it opted to maintain the existing hierarchy, with safety-of life messages receiving the highest priority, followed by public safety messages, and then non-priority communications. In addition to continuing to allow non-priority communications that promote road safety, the FCC declined to prohibit commercial communications.

Channel Bandwidth

The FCC opted for a light touch approach regarding channel bandwidth with modest changes to increase flexibility for companies in the early stages of implementing C-V2X. The Final Rule retains the existing three ITS channels with 10-megahertz bandwidths—5.895-5.905 GHz, 5.905-5.915 GHz, and 5.915-5.925 GHz—but abandons the channel number designations that reflected the DSRC band plan. Users can now combine any two of the 10-megahertz channels into a contiguous 20-megahertz channel or all three 10-megahertz channels into a single contiguous 30-megahertz channel without restriction to accommodate a variety of ITS applications and services. 

Communications Zones

The new C-V2X rules no longer require operators to designate intended areas of operations, or “communications zones,” for roadside units to manage congestion. The FCC determined that these units were not regularly used with DSRC-based technology and are not necessary for use with C-V2X-based technology.

C-V2X Technical Requirements

The Final Rule includes updated C-V2X technical requirements for: (1) power and antenna height limits for C-V2X roadside units, (2) power limits for C-V2X on-board units, and (3) out-of-band emission limits for C-V2X roadside units and on-board units. The updates generally were intended to mitigate interference, while at the same time providing significant flexibility to the nascent C-V2X industry.

Technology Transition

The Order establishes a two year period for the transition to C-V2X, beginning on the publication date of the Second Report and Order in the Federal Register. Within two years, all ITS operations must convert to C-V2X or cease. 

Other Spectrum for ITS

The FCC affirmed its decision in the First Report and Order that the 30 megahertz of spectrum allocated for ITS in the 5.9 GHz band is sufficient to provide basic safety services. In addition, the FCC encouraged affected industry to fully test the bounds of the allocated spectrum, the C-V2X technology, and the new technical parameters, in order to inform future decisions about spectrum needs. 

Compensation and Reimbursement of Transition Costs

The FCC declined to establish a reimbursement mechanism to compensate DSRC licensees for costs associated with the transition to C-V2X or cessation of operations. The FCC noted that its action in the First Report and Order modifying all 5.9 GHz licenses to operate in the upper 30 megahertz of the band, along with the long timeline of the proceeding and the two-year transition period have allowed licensees sufficient time to address the costs of the transition within their normal budgetary cycles. 

Authored by Ari Fitzgerald and Ambia Harper.