February 23, 2015 - 5:02 pm

Today’s Wi-Fi spectrum bands are wildly popular.  But with more and more people and devices taking advantage of this technology, these bands are getting congested.  It reminds us of the famous Yogi Berra quote, “Nobody goes there anymore; it’s too crowded.” 

In response to the growing use of Wi-Fi, the Federal Communications Commission has taken steps to meet the growing demand for additional unlicensed spectrum.  Last year, we added 100 megahertz of spectrum for Wi-Fi in the lower 5 GHz band.  The Commission is also seeking to secure some unlicensed spectrum opportunities in the 600 MHz band as part of our upcoming incentive auction.  But more needs to be done—and soon.

One spectrum band that we believe needs greater attention is in the upper 5 GHz band.  In light of the proximity to spectrum in other parts of the 5 GHz band that are already used for unlicensed services, this is a prime candidate to help meet the demand for Wi-Fi.  Unlicensed services generally share spectrum with other radio services on a non-interference basis.  So one of the bands identified for potential new sharing is the 75 megahertz of spectrum located at 5850 to 5925 MHz (also known as the U-NII-4 band) that was allocated by the Commission in 1999 for Dedicated Short Range Communications Service (DSRC) systems intended to improve roadway safety. 

DSRC was intended to enable short range, wireless links to transfer information between vehicles and roadside systems.  At the time of allocation, DRSC was expected to be used for a variety of purposes, including “traffic light control, traffic monitoring, travelers’ alerts, automatic toll collection, traffic congestion detection, emergency vehicle signal preemption of traffic lights, and electronic inspection of moving trucks through data transmissions with roadside inspection facilities.”

Since then, while DSRC has been slowly developing, the demand for Wi-Fi and devices using unlicensed spectrum has exploded.  Moreover, during this time we have witnessed the development of increasingly sophisticated techniques that have enabled unlicensed devices to operate in places once unimaginable, like the broadcast television white spaces.  As a result, we believe it is imperative to look at ways for unlicensed services to operate in the U-NII-4 band.

There are a variety of ways to accomplish this goal.  Given technological advancements in alleviating interference, we should explore if unlicensed services could operate in the U-NII-4 band, without causing harmful interference to DSRC.  Alternatively, a number of parties have suggested dedicating the upper portion of the U-NII-4 band for DSRC and allowing the lower portion to be dedicated to a mix of Wi-Fi and non-critical DSRC uses.  Under either scenario, there could be exciting new possibilities for more high-speed, high-capacity Wi-Fi in the 5 GHz band. 

Furthermore, there is growing interest in the Wi-Fi opportunities in the U-NII-4 band from outside the Commission.  On Capitol Hill, Senators Rubio (R-FL) and Booker (D-NJ) have reintroduced Senate legislation from the last Congress that establishes a process, including examining interference-mitigation technologies and establishing a test plan, in order to assess and potentially allow unlicensed services to operate in the U-NII-4 band if doing so does not result in harmful interference to DSRC.  In addition, Representatives Latta (R-OH), Issa (R-CA), Eshoo (D-CA), Matsui (D-CA), and DelBene (D-WA) have reintroduced similar 5 GHz band legislation in the House of Representatives.  Separately, the Institute of Electrical and Electronics Engineers (IEEE) has begun work on the possibilities having both unlicensed devices and DSRC systems operate, although we recognize that resolution in this forum may not occur in the near term.

We also recognize based on the record before us (ET 13-49) that proponents of DSRC are reluctant to support efforts that they believe jeopardize their exclusive use of valuable spectrum.  Nonetheless, more than a decade and a half after this spectrum was set aside for vehicle and roadside systems, we believe it is time to take a modern look at the service possibilities in these airwaves.  In other words, it is time for the Commission to develop a compromise that allows both unlicensed and DSRC use in the U-NII-4 band. 

We support the safety initiatives associated with DSRC, but are mindful that mobile opportunities are multiplying in ways never contemplated when this spectrum was set aside in 1999.  After all, when DSRC was new, driverless cars were the stuff of science fiction.  Additionally, new technologies are coming to market that support features like automatic braking and lane change warnings that use radar and other technologies not dependent on DSRC.  Above all, we should not strand our spectrum strategies in turn-of-the-millennium safety technologies when there are may be other more efficient ways to reach these same goals. 

In sum, there are possibilities for greater unlicensed use in the U-NII-4 band while still permitting and protecting DSRC, and the time to make that happen is now.  By doing so, we can support automobile safety, expand the spectrum used for Wi-Fi and grow our wireless economy.  That strikes both of us as goals worth pursuing.