Getting connected to Wi-Fi can be a frustrating experience. Even if you can find a signal, your connection may be slow or unreliable. Sometimes the culprit may be many other devices trying to use the same radio frequencies at the same time. The FCC should now help alleviate this problem by creating a large, contiguous swath of high-capacity, unlicensed spectrum — the kind used for Wi-Fi.
The spectrum in question is the 5.9 GHz band. Two decades ago, the FCC allocated this band exclusively for vehicle safety technologies and connected cars. But the failure of those technologies to materialize, combined with the radical growth of unlicensed technologies like Wi-Fi and Bluetooth, suggests that reallocating the band for unlicensed use would be a more productive approach.
The Need for Unlicensed Spectrum
Unlicensed spectrum is best understood in contrast to the majority of the radio spectrum, which is subject to FCC licenses. Licenses to operate in certain spectrum bands are akin to titles to other resources: They afford the licensee a legal right to operate without interference in a certain geographic area. Licensing spectrum is a way to prevent a tragedy of the commons, in which spectrum is overused to the point that no one can communicate without interference.
But licensing is not the only governance framework capable of combating this tragedy in radio frequencies. Currently, Wi-Fi devices send and receive data using frequencies in either the 2.4 GHz or 5 GHz band. These bands are designated for “unlicensed” use, meaning that no one has the right to use them exclusively or be protected from interference.
Unlicensed spectrum replaces property-like legal rights with technical rules to prevent interference. Your Wi-Fi router, for example, has to operate within certain power levels and protocols to keep its transmissions from drowning out others. Radio frequencies used for Wi-Fi also have propagation characteristics that keep signals relatively confined within small areas or buildings. The downside of this is that you may have trouble connecting to your home’s network from the other side of the house. The upside is that no one has to pay to use the spectrum.
But as with any unpriced resource, unlicensed spectrum tends to get used quite heavily. The technical rules work to a point, but unlicensed bands are now getting congested, especially in densely populated areas. This fact alone should make policymakers cautious about designating spectrum as unlicensed too readily. But the success of technologies like Wi-Fi and Bluetooth warrants some additional unlicensed allocations.
The Trouble with 5.9 GHz
The FCC is well on its way to augmenting unlicensed allocations by permitting unlicensed use of the 6 GHz band. But in between the unlicensed 5 GHz band and the soon-to-be unlicensed 6 GHz band sits the 5.9 GHz band, which has a more checkered history. The FCC set aside the 5.9 GHz band for vehicle-to-vehicle communications technology in 1999. This move in itself was a mistaken act of central planning. The government is ill-equipped to decide how particular radio frequencies ought to be used, and the attempt to do so has resulted in inefficient and politically precarious policy decisions in the past.
While these practices have largely been replaced by more market-driven allocation, the fallout of the old model is starkly visible in the case of the 5.9 GHz band. Twenty years after it was first gifted to the auto industry, the government’s chosen technology, known as digital short-range radio communication (DSRC), still has not seen wide deployment. But as productive unlicensed uses have grown dramatically in adjacent bands, the bespoke set-aside for DSRC is now a fly in the ointment of wide channels for unlicensed wireless technologies like Wi-Fi and Bluetooth.
By designating the 5.9 GHz band for unlicensed use the FCC would create a swath of unlicensed spectrum that connects the 5 GHz and 6 GHz bands. This change would enable expansion of the number of large Wi-Fi channels, 160 MHz wide. Wider channels mean more throughput, which in turn means consumers could expect multigigabit speeds from their Wi-Fi connections — many times faster than today’s average speeds. Connecting otherwise fragmented segments of unlicensed spectrum would enable economies of scale, as wide channels can stretch across the whole set of frequencies without having to reduce the productivity of both bands as they approach frequencies protected for DSRC.
Vehicle safety is a serious concern, and cars that can talk to each other could be a lifesaving part of the future of transportation. But we need not choose between safe cars and Wi-Fi. We should just look to technologies and spectrum bands beyond DSRC and 5.9 GHz.
Other Options for Connected Cars
Indeed, automakers have been pursuing alternative vehicle communications standards such as cellular vehicle-to-everything (CV2X) technology. This technology has the support of car makers like Ford and BMW. But the virtue of connected cars is that they can talk to each other and surrounding infrastructure. If the auto industry is split between competing, non-interoperable standards, then the overall value proposition for connected vehicle technology is diminished. In short, a world of widespread connected cars is not ready yet. But the newest Wi-Fi standard, Wi-Fi 6, is already being deployed and is ready to use the 5.9 GHz and 6 GHz bands. Since this spectrum is needed for unlicensed use now, it makes sense to allow connected vehicle technologies to continue to mature using other frequencies.
Car companies should participate in market processes to acquire exactly what they need for whichever technology they choose. While it is true that this would cost them more than relying on a government handout, automakers realize that safety is worth it. As vehicle-to-everything (V2X) technology continues to mature, there are plenty of other bands to choose from. Others in the neighborhood of 5.9 GHz will be for sale soon. Portions of the 2.5 GHz, 3.5 GHz and 3.7–4.2 GHz bands will likely be repurposed for flexible use in the near future. Other spectrum bands exist that may be even more conducive to vehicle communications. Later this year, auctions of the 37, 39 and 47 GHz bands will provide opportunities to acquire spectrum with short-range propagation but high capacity — ideal for talking to nearby cars on a crowded road. And this does not even account for the possibility of private, secondary-market deals that could be struck with any existing licensee to get access to spectrum at pretty much any frequency. Existing communications companies have already partnered with automakers to connect vehicles in other ways; adding V2X as a service would be a reasonable step.
Moreover, autonomous vehicle manufacturers are making great strides in improving automobile safety without relying on two-way radio technologies at all. Companies like Waymo, General Motors and Tesla are deploying automated systems that use lidar, radar, cameras, and detailed mapping to navigate safely. Perhaps these vehicles will eventually incorporate connected-car technologies as well, but until there is wider agreement among the automotive industry on wide deployment of some interoperable standard, it is not credible to insist that access to any particular band is a necessary prerequisite to improving road safety.
While all technological developments take time, the rest of the wireless world hasn’t stood still waiting for DSRC. Even if DSRC was the best use of the 5.9 GHz band in the 1990s, the wireless ecosystem has changed. Unlicensed technologies and devices have advanced and proliferated, and the spectrum bands dedicated to them are filling up. As the FCC takes the logical next steps to extend unlicensed allocations up through the 6 GHz band, it should not let vestiges of spectrum central planning stand in the way.
Image credit: jamesteohart