Tuesday, June 11, 2019

U.S. Policymakers Should Stick to Their 24 GHz Spectrum Band Plan

On June 3, the FCC announced winners in the successful auction of 5G-critical spectrum licenses in the 24 GHz band, raising $2 billion for the U.S. Treasury. Yet news outlets have reported on last-minute objections by agencies within the U.S. Department of Commerce to use of this spectrum that had been planned through a careful interagency process. U.S. policymakers shouldn't be deterred. It's important to the integrity of U.S. spectrum policy and to 5G deployment that the 24 GHz spectrum be used as planned. 

Rules regarding 24 GHz spectrum use were established through a five-year interagency process, and they are consistent with longstanding FCC standards limiting out-of-band emissions. Agencies in the Commerce Department have made claims, apparently without reliable and verifiable evidence, that 5G operations in the 24 GHz band could interfere with a weather sensor in an adjacent band. But their calls to change rules for the 24 GHz band, now echoed by some members of Congress, threaten the integrity of the interagency process and U.S. spectrum policy in international circles. Changes to rules would upend the investment-backed expectations of auction winners and hamper 5G deployment.

Indeed, there are many reasons to be skeptical of claims being made by NASA and Department of Commerce agencies NTIA and the National Oceanic and Atmospheric Administration (NOAA) about future interference with a single weather sensor. 

First, the claims by the Commerce Department agencies didn't timely persuade other agencies that were part of the 5-year interagency spectrum planning process. According to a March 8 letter to the Commerce Secretary and NASA Administrator by Chairman Ajit Pai: "For over two years, the studies produced by NOAA were never endorsed by either the FCC or NTIA due to outstanding technical concerns" and "[t]he interagency consensus was that these studies failed to demonstrate a need to tighten the international limits." Agencies may validly seek to influence policy based on alleged signal interference during the process but shouldn't do so after, when the FCC has already auctioned the spectrum. 

Second, Chairman Pai's March 8 letter pointed out: 
In order to settle the U.S. position, the FCC thus invoked the reconciliation process in light of our upcoming auction of the 24 GHz band—a critical band for the development of 5G services in the United States. Under that process, as you know, the Department of State becomes the arbiter—'breaks the tie' if you will—and determines the U.S. Government position. That is what happened here. The Department of State agreed with the FCC's approach, and that reconciled position is in fact documented. 
The State Department agreed with the FCC's approach, and that reconciled position is in fact documented." As the U.S. strives for a leadership role in 5G, a confused spectrum policy could undermine U.S. leadership in international venues, such as the International Telecommunications Union (ITU). The U.S. government's position ought to be communicated with one voice overseas.

Third, NASA and NOAA want ad hoc changes to out-of-band emission standards for the 24 GHz band. In other words, the dispute doesn't involve alleged interference according to existing standards. In fact, the rules established for the 24 GHz band are consistent with longstanding FCC standards limiting out-of-band emissions to protect passive services from high powered fixed services. Goalpost shifting is almost always suspect. And changes to the out-of-band emission standards would significantly reduce commercial service providers' ability to offer 5G, undermining the basis for their purchase of spectrum licenses. 

Fourth, when NASA and NOAA initially raised their last-minute objections to the planned use of the 24 GHz band, those objections involved a weather sensor, known as "the Conical Microwave Imager Sounder" that was neverdeployed. Rather, those agencies expressed concerns that out-of-band emissions from 5G operations would harm a weather sensor that was cancelled in 2006. 

Fifth, although Commerce Department agencies later raised still more last-minute objections, they appear unsubstantiated. For instance, the newer objections involve one of the weather sensors on a single satellite that reportedly is acknowledged to be much less susceptible to interference than the cancelled weather sensor. And in an April 29 letter to the Chairwoman of the House Committee on Science, Space, and Technology, Chairman Pai reiterated the Commission has never been presented with "a validated study" indicating operations consistent with existing out-of-band admissions standards would adversely affect existing use in the 24 GHz band, including weather forecasting. 

Technical engineering expertise isn't necessary to spot the credibility problems with these last-minute claims by Commerce Department agencies. They have offered too little, too late to justify pulling the rug out from under the interagency spectrum process.

Commercial providers made good faith pledges of $2 billion in spectrum license bids, and the federal government owes a pledge of good faith in sticking to its rules. U.S. policymakers should stay the course on the 24 GHz band and help ensure American competitiveness in the global race to 5G.