FCC Chairman proposing taking spectrum allocated for DSRC and reallocating for unlicensed WiFi use and C-V2X
FCC Chairman Ajit Pai is proposing taking the 75 megahertz of spectrum in the 5.9 Ghz band currently allocated for Dedicated Short-Range Communications (DSRC) for the transportation and automotive industries and to reallocate it for different services.
Under his Notice of Proposed Rulemaking, which will be considered at the 12 December FCC Open Meeting, the lower 45 MHz of the band would be made available for unlicensed uses such as WiFi and the upper 20 MHz would be allocated to Cellular Vehicle to Everything, (C-V2X). Pai suggests seeking public input as to whether to allocated the remaining 10 MHz in the band to C-V2X or DSRC.
Back in 1999, the FCC allocated 75 megahertz of spectrum in the 5.9 GHz band for a service called Dedicated Short-Range Communications. Commonly known as DSRC, this technology was intended to enable ubiquitous transportation and vehicle-related communications. But results haven’t matched that intent. Here we are, two decades later, and the situation can at best be described as “promise unfulfilled.” DSRC has evolved slowly. It’s not widely deployed. And in the meantime, a wave of new transportation communication technologies has emerged. As a result, a lot of people are wondering whether this valuable spectrum—a public resource—is really being put to its best use.
In my view, it clearly is not. After 20 years of seeing these prime airwaves go largely unused, the time has come for the FCC to take a fresh look at the 5.9 GHz band.—Chairman Pai
WiFI’s popularity has created a problem for regulators, Pai said. Estimates suggest that the US will need to allow use of up to 1.6 GHz of new mid-band spectrum by 2025 to keep up with demand.
Last October, the FCC began to explore opening up a massive 1,200 megahertz of spectrum in the 6 GHz band for different types of unlicensed uses.
The lower 45-megahertz portion of the 5.9 GHz band proposed as being shifted to unlicensed operations is adjacent to the 5.725-to-5.850 GHz band which is currently available for unlicensed operations. That makes the 45 MHz sub-band ideally suited for unlicensed use, Pai said. Having more contiguous spectrum here is essential for the larger channels needed to support innovative use cases, he added.
It’s important to note that my proposal marks a departure from our recent exploration of allowing unlicensed devices to share the same spectrum with DSRC. Preliminary testing of a sharing regime showed some promise, but further testing would be needed to carry out a complex sharing regime, and more testing would mean this valuable spectrum would likely lie fallow for several years. As it is, this valuable mid-band spectrum has been lying largely fallow for two decades. We are well past the point where American consumers should accept significant additional delays in putting this spectrum to use for them. And it’s not just that sharing spectrum between unlicensed uses and DSRC would take time. It also adds complexity and raises the question of whether, given its past, DSRC is a technology with a future. That’s why I believe the best course is to dedicate 45 MHz exclusively for unlicensed operations, and also to establish a home exclusively for transportation-related communications.Chairman Pai
Pai argues that many of the features originally envisioned for DSRC are being provided today by other means, even by apps such as Waze Further, he notes that C-V2X is a promising technology that is gaining momentum in the automotive industry.
Based on the evidence in the public record, I believe that we should encourage the expansion and evolution of this new vehicle-safety technology. That’s why I’m proposing that we authorize C-V2X operations in the upper 20 megahertz of the 5.9 GHz band. Our hope is that this move will unlock new vehicle safety services, using less spectrum and on a much faster timeline than we have seen or realistically could see with a DSRC-focused policy.
Now, just because we’re changing course and prioritizing C-V2X technology doesn’t mean we’re closing the door entirely on DSRC. Even after 20 years, we are once again being told that DSRC technology is about to take off. Japan, for example, has a single 10-megahertz channel for DSRC that is actively used for collision avoidance around intersections. So I’m proposing that we seek public input on whether to allocate the remaining 10 MHz of spectrum in the 5.9 GHz band for DSRC or C-V2X. Advocates of each will be able to make their case.—Chairman Pai