FEDERAL COMMUNICATIONS COMMISSION 
                                   WASHINGTON 

        
OFFICE OF THE 
  CHAIRWOMAN                            September 14, 2022 
   
   
  The Honorable Bill Johnson 
  U.S. House of Representatives  
  2336 Rayburn House Office Building  
  Washington, DC 20515  
   
  Dear Representative Johnson:  

        Thank you for your letter regarding the ongoing proceeding at the Federal 
  Communications Commission concerning Expanding Flexible Use of the 12.2-12.7 GHz band 
  (the 12GHz band).  The Commission started this proceeding in January 2021 to allow interested 
  parties to address whether additional operations could be accommodated in this band without 
  causing harmful interference to incumbent users.  I understand and share your interest in 
  ensuring that existing services in this band—including high-speed internet services to rural and 
  underserved areas of the country—are not disrupted as the agency considers any action in this 
  proceeding.   

        There are now three services authorized and operating in the 12 GHz band.  Historically, 
  this band was used for Direct Broadcast Satellite Service and Multi-Channel Video and Data 
  Distribution Service.  More recently, proponents of a new generation of satellite operations have 
  received authorization from the Commission to launch and operate constellations of hundreds or 
  thousands of satellites using several frequency bands, including the 12 GHz band.  Thousands of 
  satellites have been launched already, with new commercial satellite broadband services rolling 
  out across the country.  Last month, the Commission granted the applications of two satellite 
  operators to use Earth Stations in Motion to deliver high quality, low latency broadband services 
  to vehicles, boats, and aircraft while complying with Commission rules for coordination and 
  spectrum sharing. 

       In the ongoing proceeding, the Commission is evaluating two potential approaches to 
 future use of the 12 GHz band:  increasing terrestrial use of the shared band or continuing with 
 the current framework.  This will require carefully examining the characteristics of this spectrum 
 band—including its propagation and capacity characteristics, the nature of in-band and adjacent 
 band incumbent use, and the potential for international harmonization—before deciding whether, 
 and if so, how, to make it available for more intensive terrestrial or satellite use.  This is a 
 complex engineering process that involves analyzing competing technical analyses.  For 
 example, the agency is considering the criteria that should be used for assessing interference 
 between mobile and satellite services.  This is important because one study in our record points 
 to an interference-to-noise ratio based on an ITU-R specification that applies to terrestrial and 
 satellite interference, while others advocate for a more stringent threshold that some satellite 

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 systems are required to use to coordinate among themselves under FCC rules.  In addition, we 
 are studying how to model the increase in probability of interference to satellite user terminals 
 and how to determine what level of probability increase, if any, should be determined as 
 acceptable.  Work is also underway regarding the specific assumptions that should be made 
 regarding the operational parameters and technical specifications of satellite user terminals in the 
 band—such as how many there will be, what will be the separation distances between satellite 
 user terminals and 5G stations, what will be the elevation angle, antenna height, and antenna gain 
 of the satellite user terminals—and how best to structure a Monte Carlo simulation.  
 Furthermore, we are determining what propagation model should be used to assess how the 
 radiofrequency energy from 5G transmitters will travel and dissipate in rural, suburban, urban, 
 and dense urban environments.  In our record, some parties point to a 3GPP model, while others 
 assert that an ITU-R specification is more appropriate.  A wide range of legal, technical, and 
 policy experts from the FCC’s Wireless Telecommunications Bureau, International Bureau, and 
 Office of Engineering and Technology are engaged in this review and coordinating, as necessary, 
 with other federal authorities in the process.     

      I appreciate your interest in this matter.  As we move forward, the Commission will fully 
take into account the needs of consumers and existing users.  Please let me know if I can be of 
any further assistance. 

                                    Sincerely, 

                                                                     
                                     Jessica Rosenworcel