Modifying Emissions Limits for the 24.25-24.45 GHz and 24.75-25.25 GHz Bands

<RULE> FEDERAL COMMUNICATIONS COMMISSION <CFR>47 CFR Parts 2 and 30</CFR> <DEPDOC>[ET Docket No. 21-186; FCC 24-124; FR ID 267422]</DEPDOC> <SUBJECT>Modifying Emissions Limits for the 24.25-24.45 GHz and 24.75-25.25 GHz Bands </SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Communications Commission. <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> In this document, the Federal Communications Commission (Commission) revises the Commission's rules for the 24.25-24.45 GHz and 24.75-25.25 GHz bands (collectively, the 24 GHz band) to implement certain decisions made in the World Radiocommunication Conference held by the International Telecommunication Union (ITU) in 2019 (WRC-19). Specifically, the Commission aligns part 30 of the Commission's rules for mobile operations in these frequencies with the Resolution 750 limits adopted at WRC-19 to protect the passive 23.6-24.0 GHz band from unwanted emissions on the timeframes adopted at WRC-19. </SUM> <DATES> <HD SOURCE="HED">DATES:</HD> <E T="03">Effective date:</E> This rule is effective January 13, 2025. </DATES> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Simon Banyai of the Wireless Telecommunications Bureau, Broadband Division, at 202-418-1443 or by email to <E T="03">Simon.Banyai@fcc.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> This is a summary of the Commission's <E T="03">Report and Order</E> in ET Docket No. 21-186; FCC 24-124; adopted on November 27, 2024 and released on December 2, 2024, 2024. The full text of this document is available at <E T="03">https://docs.fcc.gov/public/attachments/FCC-24-124A1.pdf</E> . <E T="03">Regulatory Flexibility Act.</E> The Regulatory Flexibility Act of 1980, as amended (RFA), requires that an agency prepare a regulatory flexibility analysis for notice-and-comment rulemakings, unless the agency certifies that “the rule will not, if promulgated, have a significant economic impact on a substantial number of small entities.” Accordingly, the Commission has prepared a Final Regulatory Flexibility Analysis (FRFA) concerning the possible impact of the rule changes contained in this <E T="03">Report and Order</E> on small businesses. The FRFA is set forth in the back of this document. <E T="03">Paperwork Reduction Act.</E> This document does not contain new or modified information collection requirements subject to the Paperwork Reduction Act of 1995 (PRA), Public Law 104-13. In addition, therefore, it does not contain any new or modified information collection burden “for small business concerns with fewer than 25 employees,” pursuant to the Small Business Paperwork Relief Act of 2002, Public Law 107-198, see 44 U.S.C. 3506(c)(4). <E T="03">Congressional Review Act.</E> The Commission has determined, and the Administrator of the Office of Information and Regulatory Affairs, Office of Management and Budget, concurs, that this rule is non-major under the Congressional Review Act, 5 U.S.C. 804(2). The Commission will send a copy of this Report & Order to Congress and the Government Accountability Office pursuant to 5 U.S.C. 801(a)(1)(A). <E T="03">People With Disabilities.</E> To request materials in accessible formats for people with disabilities (braille, large print, electronic files, audio format), send an email to <E T="03">fcc504@fcc.gov</E> or call the Consumer and Governmental Affairs Bureau at (202) 418-0530 (voice). <HD SOURCE="HD1">Synopsis</HD> <HD SOURCE="HD1">I. Background</HD> 1. The 23.6-24.0 GHz band is allocated to several passive scientific and research services, including the Earth Exploration Satellite Service (EESS) (passive), on a primary basis. EESS utilizes passive sensors located on satellites to measure the power level of naturally occurring radio emissions from water vapor and cloud liquid water molecules in the atmosphere, which are critical measurements for climatology and weather forecasting. Because naturally occurring radio emissions in the 23.6-24.0 GHz band are very weak, the passive sensors that measure them are sensitive and vulnerable to interference. 2. Observations made by EESS sensors operating in the 23.6-24.0 GHz band are essential for meteorological applications. The National Oceanic and Atmospheric Administration (NOAA) uses EESS to take measurements considered vital to the accuracy and timeliness of weather forecasting, including hurricane and tornado warnings, and the National Aeronautics and Space Administration (NASA) also operates passive EESS systems in the band to conduct climatological science. Additionally, EESS passive sensors aid EESS active instruments that use radar on satellites to measure ocean topography, sea ice, and precipitation by measuring total atmospheric water vapor and correcting the “refraction-induced path delay in the radar signal.” The 23.6-24.0 GHz band has been used for passive sensor observations for a considerable length of time and has generated valuable long-term climate data records. 3. The Commission first authorized service in the 24.25-24.45 GHz and 25.05-25.25 GHz bands in 1997, when it transitioned the Digital Electronic Messaging Service (DEMS) to these bands from the 18 GHz band. In 2000, the Commission adopted competitive bidding and service rules for 24.25-24.45 GHz and 25.05-25.25 GHz bands and created a 24 GHz Service. This 24 GHz Service had a total of 176 Economic Areas (EAs) or EA-like service areas. In 2004, the Commission held Auction 56, in which it made 880 24 GHz Service licenses available. Only seven of the 880 24 GHz Service licenses were sold. As of 2017, there were 33 active DEMS licenses in these bands. While the former DEMS licenses were converted to Upper Microwave Flexible Use Services (UMFUS) licenses, they were subsequently cancelled. 4. In 2016, the Commission adopted licensing and technical rules for UMFUS services in the 27.5-28.35 GHz band, the 37.6-38.6 GHz band, and the 38.6-40 GHz band. Expanding on the 2016 efforts to open high-frequency spectrum, in 2017, the Commission authorized the 24 GHz band for UMFUS, and generally applied the same licensing and technical rules to UMFUS in the 24 GHz band that it applied to UMFUS in other upper microwave bands. The UMFUS rules allow licensees flexibility to the services they will deploy and the architecture of their networks. Under these rules, licensees are able to deploy mobile services, but they also may deploy fixed point-to-point and point-to-multipoint systems. Among other things, the UMFUS rules specify that emissions outside of a licensee's assigned frequency block must be limited to −13 dBm/MHz. <SU>1</SU> <FTREF/> In its decision authorizing UMFUS in the 24 GHz band, the Commission noted ongoing ITU studies to establish emissions limits applicable to International Mobile Telecommunications (IMT) to protect passive sensors in the 23.6-24.0 GHz band, and it acknowledged that the UMFUS rules might be revisited once the ITU studies had been completed. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  See 47 CFR 30.203(a). In the bands immediately outside and adjacent to the licensee's frequency block, having a bandwidth equal to 10 percent of the channel bandwidth, the conductive power or the total radiated power of any emission shall be −5 dBm/MHz or lower. Id. As the 23.6-24 GHz passive band is 250 megahertz away from the UMFUS bands, the −5 dBm/MHz does not apply within that passive band for UMFUS licensees. </FTNT> <FTNT> <SU>2</SU>  IMT is the generic term used by the ITU to designate broadband mobile systems and encompasses IMT-2000, IMT-Advanced, and IMT-2020. See ITU, Radiocommunication Sector ITU-R FAQ on International Telecommunications (Feb. 23, 2022), <E T="03">https://www.itu.int/en/ITU-R/Documents/ITU-R-FAQ-IMT.pdf.</E> As described below, the Commission rules do not define IMT. </FTNT> 5. WRC-19 allocated 24.25-25.25 GHz to mobile (except aeronautical) on a primary basis in Regions 1 and 2, globally identified the 24.25-27.5 GHz band for IMT, and established unwanted emissions limits applicable to IMT in the 24.25-27.5 GHz band to protect passive systems in the 23.6-24.0 GHz band. To implement these limits, WRC-19 modified a footnote to the International Table of Allocations to add Resolution 750 (Rev. WRC-19). Resolution 750 specifies unwanted emissions limits in terms of Total Radiated Power (TRP) as the amount of power that may be radiated into any 200 megahertz block of the 23.6-24.0 GHz passive band by IMT base stations and IMT mobile stations operating in the 24.25-27.5 GHz band. Resolution 750 sets emissions limits for current IMT devices as well as more stringent emissions limits for IMT devices that will be brought into use in the 24.25-27.5 GHz band after September 1, 2027. These two sets of unwanted emissions limits are shown in Table 1. <GPOTABLE COLS="3" OPTS="L2,nj,i1" CDEF="s100,r100,r100"> <TTITLE>Table 1—WRC-19 Resolution 750 Unwanted Emissions Permitted Within Any 200 Megahertz in the 23.6-24 GHz Passive Band</TTITLE> <CHED H="1">Type of station</CHED> <CHED H="1">Current TRP limits</CHED> <CHED H="1">TRP limits after Sept. 1, 2027</CHED> <ROW> <ENT I="01">IMT Base Stations</ENT> <ENT>−33 dBW</ENT> <ENT>−39 dBW.</ENT> </ROW> <ROW> <ENT I="01">IMT Mobile Stations</ENT> <ENT>−29 dBW</ENT> <ENT>−35 dBW.</ENT> </ROW> </GPOTABLE> 6. On April 26, 2021, the Office of Engineering and Technology (OET) and the Wireless Telecommunications Bureau (WTB) issued a <E T="03">Public Notice</E> (86 FR 28522) to develop a record on whether and how the Commission could implement the emissions limits contained in Resolution 750 for the active services in the 24 GHz band. The <E T="03">Public Notice</E> sought comment on amending part 30 of the Commission's rules to conform to the unwanted emissions limits into the passive 23.6- ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 80k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━