Weather Forecasting or 5G? Why Not Both?
In 2019, a lot of us check the weather on our smartphones. But some in the federal government think this simple act constitutes having our cake and eating it too. The National Oceanic and Atmospheric Administration (NOAA) is trying to halt the rollout of next-generation wireless services, or 5G, in the 24 GHz band by claiming that it would interfere with weather satellites. But these claims are unsubstantiated. The 5G rollout should be allowed continue so it can eventually enable faster, more reliable connectivity for everything from weather reports to WhatsApp.
Whenever the FCC seeks to allow private use of frequencies in or around bands used by government agencies, it takes precautions to ensure that critical government missions are not harmed. For the 24 GHz band, this process was completed in November of 2017 when the FCC adopted an order based on an open process in which any interested party had an opportunity to comment. Last August, the procedures for auctioning the band were finalized.
However, in March of this year, on the eve of the auction, complaints began to surface in Congress suggesting a change of tune from the NOAA and the National Telecommunications and Information Administration (NTIA), the Commerce Department agency responsible for managing spectrum used by government agencies. The NOAA and NTIA insisted that allowing 5G in the 24 GHz band would interfere with data collection carried out by weather satellites in the neighboring 23.6 GHz band. These objections reached fever pitch when NOAA testimony suggested hurricane forecasts would become wildly inaccurate if terrestrial wireless services were deployed in the 24 GHz band according to the FCC’s parameters.
The concerns are based on the potential for 5G services that use 24 GHz on the ground to create harmful interference for weather satellites that sense moisture in the atmosphere using the 23.6 GHz band. Harmful interference would mean that 5G signals in the 24 GHz band are so powerful that they spill over into the neighboring band and make weather data less accurate. But this kind of interference is mitigated by setting out-of-band emission limits.
There is good cause to think that weather satellites would not experience harmful interference from 5G operations in the 24 GHz band under the current FCC limits. Terrestrial services are already operating just below the 23.6 GHz band used by weather satellites. Those services operate under the same noise limit, -20 dBW/200 MHz, that the FCC has provided for 5G operations in the 24 GHz band.
In other words, this noise limit has a track record of successfully protecting weather satellites. FCC Chairman Ajit Pai testified last week, “Before we made our decision there were some 40,000 microwave links in the band immediately adjacent to the 23.6 GHz band that’s in question. There’s never been a reported case of interference.” Moreover, 5G services in the 24 GHz band would be separated from weather satellite operations by a 250 MHz “guard band.” Since this feature is not present in the band immediately below the one used by weather satellites, there is even more reason to think the weather satellites will be safe from interference from the 24 GHz band.
Of course, this reasoning is rebuttable by scientists and engineers at the NOAA, NASA and the NTIA. But the objections raised so far have not been accompanied by such a rebuttal. It is no wonder, therefore, that Chairman Pai spoke of his own frustration with demands that the noise limit be at least twice as strict: “Over the last two and a half years we’ve patiently waited for a validated study to suggest that our proposed limit is inappropriate. We’ve never gotten such a validated study.”
One study analyzed the effect of the FCC noise limit on a sensor that is not in use. There have been rumors of another study addressing an in-use sensor, but it is reportedly only in draft form and was recently removed from NASA’s website. And NOAA’s simulations may not account for technical characteristics of 5G that make it less likely to interfere with its neighbors.
The process through which the executive agencies raised their objections also warrants skepticism. Not only have their claims been unamenable to evaluation by private stakeholders or the FCC, they also threaten the diplomatic position of the United States in international negotiations on spectrum policy. It is important that United States can speak with one voice during international meetings on the wireless ecosystem such as the International Telecommunication Union’s fast-approaching World Radiocommunication Conference. The uncertainty created by the agencies’ unsubstantiated doomsday predictions about the 24 GHz band threatens to undermine U.S. interests in international spectrum coordination.
Overall, observers are left in confusion that stems from the apparently tumultuous current state of the NTIA, as reports suggest that the sudden departure of Administrator David Redl may reflect deeper rifts within the Commerce Department about the future of U.S. spectrum policy. In his testimony, Chairman Pai characterized the situation saying, “Some folks in the federal government believe, wrongly, that the development of 5G in this and other bands shouldn’t happen….The Department of Commerce has been blocking our efforts at every single turn.” Clearly, the 24 GHz band could become part of a larger fight.
It is a major problem if government interests are allowed to halt private wireless deployment with tenuous prophecies of disaster. The FCC is right to stand against calls to prioritize government agencies over consumer access to next generation wireless services that will enhance the wireless applications of today and enable the yet-unknown innovations of tomorrow. Congress too should join the side of consumers with appropriate oversight and legislation to prevent bureaucracy from eroding the benefits of 5G for all Americans.
