ITU-R: Managing the radio-frequency spectrum for the world

1. Establishment and updating of international regulations on the use of radio-frequency spectrum and satellite orbits

Radio Regulations (RR)

The foundation of international frequency management is the Radio Regulations (RR), the binding international treaty that determines how the radio frequency spectrum is shared between different services, including space services. Covering terrestrial fixed and mobile radio services, satellite-based services, sound and video broadcasting, radionavigation, meteorological tracking and forecasting, space research and Earth exploration, as well as amateur radio, the RR encompasses over 2300 pages of texts and charts that specify how equipment and systems must operate to ensure successful coexistence of services in today's increasingly crowded airwaves.

World Radiocommunication Conferences (WRCs) 

ITU-R reviews and updates the RR through World Radiocommunication Conferences (WRCs), which meet every four years for a period of four weeks. At WRC-23 held in Dubai, United Arab Emirates, ITU Member States agreed on revisions to the Radio Regulations, identifying new spectrum resources to support technological innovation, deepen global connectivity, increase access to and equitable use of space-based radio resources, and enhance safety at sea, in the air, and on land.

Nearly 4,000 delegates from 163 Member States attended WRC-23, including 88 ministerial-level participants. Women made up 22 per cent of all WRC-23 delegates, an increase from 18 per cent at WRC-19 in 2019.

A total of 151 Member States signed the WRC-23 Final Acts. The Final Acts constitute a record of the decisions taken at the conference including both the new and revised provisions of the Radio Regulations, all Appendices, and the new and revised Resolutions and ITU-R Recommendations incorporated by reference into the treaty by the conference.

WRCs review the way specific portions of the radio spectrum are allocated, along with procedures for coordinating, notifying and recording of frequency assignments and Plan modifications. WRCs bring together governments to negotiate and agree on the relevant modifications to the RR, typically to allow for the introduction of new radio services and systems.

Preparations for WRCs involve extensive studies and preparatory discussions among all stakeholders (government regulators, and public and private sector users of spectrum, as well as their equipment suppliers) at the national, regional, and worldwide levels. Many of these stakeholders also serve as members of national delegations at the conference itself. This multi-stakeholder approach ensures consensus, so the RRs provide a stable, predictable, and universally applied regulatory environment that secures the trillions of dollars of long-term investments of radio systems.

The agenda of a WRC includes the review and update of the global technical, operational, and regulatory provisions that govern the use of the radio-frequency spectrum for terrestrial and satellite applications. In conducting its activities, the conference attempts to cast a proper balance:

• between the need for worldwide harmonization (to benefit from economies of scale, connectivity, and interoperability) and the need for flexibility in spectrum allocations,
• ​between the need to accommodate new and innovative systems, applications, and technologies as they arise and the need to protect existing radiocommunication services, including from non-radio equipment and appliances.

Radio Regulations Board (RRB)

The international regulations on spectrum, as adopted by WRCs through a revision of the RR, are complemented by Rules of Procedure (RoPs), which clarify the way in which the provisions of the RR are to be applied. These RoPs are adopted by the Radio Regulations Board (RRB), which consists of 12 elected members selected for their qualification, experience, and regional representation. 

2. Implementation and application of international regulations on the use of the radio-frequency spectrum and satellite orbits

The RR contain several regulatory provisions and procedures which describe how the administrations from the 193 ITU Member States may acquire and exercise rights to use spectrum in the various frequency bands allocated for this purpose, and the corresponding obligations. These rights and obligations may then be transferred to the operators of each specific radiocommunication station through a license delivered by or on behalf of the government of the corresponding country.

Administrations apply these provisions and procedures daily, in close interaction with BR.

International Frequency database

A key element of international frequency management is the Master International Frequency Register (MIFR). The MIFR is a database which contains the spectrum characteristics ("frequency assignments") of the radio stations in operation throughout the world and confers to these stations international recognition and protection against interference. This database is managed by BR and currently contains 3.1 million frequency assignments for terrestrial services and over 70 000 are added every year. For space services, more than 4.1 million of assigned frequencies are contained in this database. In addition, about 215 000 assigned frequencies for the broadcasting-satellite service and 15 000 allotted frequencies for the fixed-satellite service are planned for future uses.

The procedures specified by the RR to record new frequency assignments in the MIFR are designed to ensure that every new spectrum usage in a particular geographical location is compatible with the ones previously received. In many cases, coordination between the administrations and operators involved is necessary to ensure this compatibility.

Application of these procedures ensures an interference-controlled environment for both terrestrial and satellite systems and guarantees equitable access to use of the resources of the frequency spectrum and geostationary-satellite orbit.

BR regularly reviews the content of the MIFR to ensure that it is consistent with actual use. It publishes the list of maritime and coast radio stations, which is a key element in ensuring safety of life at sea. It also provides assistance to administrations in applying these procedures and in resolving cases of harmful interference, which currently concerns 1 in 5 000 assignments.

When situations arise of disagreement between administrations or between administrations and the Radiocommunication Bureau, the RRB may consider the issue, although decisions by the RRB may be appealed to the next WRC.  

3. Establishment and updating of worldwide recommendations, reports, and handbooks for the most efficient use of the radio-frequency spectrum and satellite orbits, including best practices on national spectrum management activities

Worldwide technical standards

ITU-R also plays a central role in developing global standards for radio-based telecommunications systems, including terrestrial and space systems, as well as best practices on national spectrum management activities. The worldwide technical standards (ITU-R Recommendations) are developed within the six Study Groups of ITU-R, which gather experts drawn from government, industry, academia, and regional and international organizations, who collaborate in establishing the characteristics of the systems and services that will define tomorrow's wireless landscape.

ITU-R follows closely the increasing levels of radio-frequency noise in the environment and the consequential increase in instances of electromagnetic interference on several radiocommunication services. ITU‐R alerts regularly and collaborates with the concerned standardization organizations towards the monitoring and possible reduction of the above-mentioned phenomena. Another important role of ITU-R Study Groups is to conduct the technical, economic, regulatory, and operational studies in preparation and in support of WRC decisions.

In December 2023, ITU published the framework for the development of standards and radio interface technologies for the sixth generation of mobile systems, popularly referred to as 6G. The details are contained in Recommendation ITU-R M.2160 on the "IMT-2030 Framework" approved by the ITU Radiocommunication Assembly (RA-23) in Dubai, United Arab Emirates.

ITU-R Study Groups

The ITU-R Study Groups undertake studies and develop the technical bases for decisions to be taken at World Radiocommunication Conferences (WRCs), as well as develop international standards (ITU-R Recommendations) on radiocommunication matters.  Generally, ITU-R recommendations are of a voluntary nature. However, a WRC may decide to incorporate by reference into the Radio Regulations, in part or wholly, specific ITU-R Recommendations, making their application mandatory.  

ITU R Study Groups are established and assigned Study Questions by a Radiocommunication Assembly to prepare draft Recommendations, Reports and Handbooks etc. for approval by ITU Member States. Each Study Group can establish Working Parties (WPs), to address the various subjects within their mandate. At present, there are six Study Groups (SGs):

• Sp​ectrum management
• Radiowave propagation  
• Satellite services  
• Terrestrial services  
• Broadcasting service
• Science services  

More than 5 000 specialists, from administrations, specialized agencies, the whole telecommunication industry, and academic organizations participate in the work of the Study Groups on topics such as efficient management and use of the spectrum/orbit resource, radio systems characteristics and performance, spectrum monitoring and emergency radiocommunications for public protection and disaster relief, etc.

ITU-R Recommendations are good for business, for governmental operations and for the scientific community – driving economies of scale and economic development, supporting essential safety of life services, particularly safety at sea; enabling electronic news gathering and distribution; tracking aircraft and providing for air traffic control; enabling weather forecasting; providing for space travel and exploration etc. They are also essential to the proper and spectrally efficient functioning of all radio equipment in an environment where virtually everyone is now using spectrum resources.

4. Information and assistance to ITU-R membership in radiocommunication matters

To inform and help its membership adapt to the results of its activities in adopting international regulations, global standards and best practices on spectrum use, ITU-R also regularly holds seminars, workshops, and symposia.

These address a range of issues, currently ranging from broadband and mobile applications, transition to digital television and allocation of the digital dividend, efficient use of the spectrum/orbit resources, and emerging spectrum management techniques.

This activity is also part of ITU's efforts to promote at all levels the creation of an enabling environment for the development of a sustainable and efficient use of spectrum at the most affordable price in all regions of the world.

WRC-23 also approved the agenda items for the next World Radiocommunication Conference (WRC-27) and the provisional agenda for WRC-31. This sets the stage for the development of future technologies and guides the work of ITU–R during the next four-year study cycle:

WRC-27 agenda

• 1.1 to consider the technical and operational conditions for the use of the frequency bands 47.2-50.2 GHz and 50.4-51.4 GHz (Earth-to-space), or parts thereof, by aeronautical and maritime earth stations in motion communicating with space stations in the fixed-satellite service and develop regulatory measures, as appropriate, to facilitate the use of the frequency bands 47.2-50.2 GHz and 50.4-51.4 GHz (Earth-to-space), or parts thereof, by aeronautical and maritime earth stations in motion communicating with geostationary space stations and non-geostationary space stations in the fixed-satellite service, in accordance with Resolution 176 (Rev.WRC-23); 
• 1.2 to consider possible revisions of sharing conditions in the frequency band 13.75-14 GHz to allow the use of uplink fixed-satellite service earth stations with smaller antenna sizes, in accordance with Resolution 129 (WRC-23);
• 1.3 to consider studies relating to the use of the frequency band 51.4-52.4 GHz to enable use by gateway earth stations transmitting to non-geostationary-satellite orbit systems in the fixed-satellite service (Earth-to-space), in accordance with Resolution 130 (WRC‐23);
• 1.4 to consider a possible new primary allocation to the fixed-satellite service (space-to-Earth) in the frequency band 17.3-17.7 GHz and a possible new primary allocation to the broadcasting-satellite service (space-to-Earth) in the frequency band 17.3-17.8 GHz in Region 3, while ensuring the protection of existing primary allocations in the same and adjacent frequency bands, and to consider equivalent power flux-density limits to be applied in Regions 1 and 3 to non-geostationary-satellite systems in the fixed-satellite service (space-to-Earth) in the frequency band 17.3‐17.7 GHz, in accordance with Resolution 726 (WRC‐23);
• 1.5 to consider regulatory measures, and implementability thereof, to limit the unauthorized operations of non-geostationary-satellite orbit earth stations in the fixed-satellite and mobile-satellite services and associated issues related to the service area of non-geostationary-satellite orbit satellite systems in the fixed-satellite and mobile-satellite services, in accordance with Resolution 14 (WRC‐23);
• 1.6 to consider technical and regulatory measures for fixed-satellite service satellite networks/systems in the frequency bands 37.5-42.5 GHz (space-to-Earth), 42.5-43.5 GHz (Earth-to-space), 47.2-50.2 GHz (Earth-to-space) and 50.4-51.4 GHz (Earth-to-space) for equitable access to these frequency bands, in accordance with Resolution 131 (WRC‐23);
• 1.7 to consider studies on sharing and compatibility and develop technical conditions for the use of International Mobile Telecommunications (IMT) in the frequency bands 4 400-4 800 MHz and 7 125-8 400 MHz (or parts thereof), and 14.8-15.35 GHz taking into account existing primary services operating in these, and adjacent, frequency bands, in accordance with Resolution 256 (WRC‐23);
• 1.8 to consider possible additional spectrum allocations to the radiolocation service on a primary basis in the frequency range 231.5-275 GHz and possible new identifications for radiolocation service applications in frequency bands within the frequency range 275-700 GHz for millimetric and sub‐millimetric wave imaging systems, in accordance with Resolution 663 (Rev.WRC‐23);
• 1.9 to consider appropriate regulatory actions to update Appendix 26 to the Radio Regulations in support of aeronautical mobile (OR) high frequency modernization, in accordance with Resolution 411 (WRC‐23);​ 
• 1.10 to consider developing power flux‐density and equivalent isotropically radiated power limits for inclusion in Article 21 of the Radio Regulations for the fixed-satellite, mobile-satellite and broadcasting-satellite services to protect the fixed and mobile services in the frequency bands 71‐76 GHz and 81-86 GHz, in accordance with Resolution 775 (Rev.WRC‐23);
• 1.11 to consider the technical and operational issues, and regulatory provisions, for space-to-space links among non-geostationary and geostationary satellites in the frequency bands 1 518‐1 544 MHz, 1 545-1 559 MHz, 1 610-1 645.5 MHz, 1 646.5-1 660 MHz, 1 670-1 675 MHz and 2 483.5-2 500 MHz allocated to the mobile-satellite service, in accordance with Resolution 249 (Rev.WRC‐23);
• 1.12 to consider, based on the results of studies, possible new allocations to the mobile‐satellite service and possible regulatory actions in the frequency bands 1 427-1 432 MHz (space-to-Earth), 1 645.5-1 646.5 MHz (space-to-Earth) (Earth-to-space), 1 880-1 920 MHz (space-to-Earth) (Earth-to-space) and 2 010-2 025 MHz (space-to-Earth) (Earth-to-space) required for the future development of low-data-rate non-geostationary mobile‐satellite systems, in accordance with Resolution 252 (WRC‐23);
• 1.13 to consider studies on possible new allocations to the mobile-satellite service for direct connectivity between space stations and International Mobile Telecommunications (IMT) user equipment to complement terrestrial IMT network coverage, in accordance with Resolution 253 (WRC-23);
• 1.14 to consider possible additional allocations to the mobile-satellite service, in accordance with Resolution 254 (WRC‐23);
• 1.15 to consider studies on frequency-related matters, including possible new or modified space research service (space-to-space) allocations, for future development of communications on the lunar surface and between lunar orbit and the lunar surface, in accordance with Resolution 680 (WRC‐23);
• 1.16 to considerstudies on the technical and regulatory provisions necessary to protect radio astronomy operating in specific Radio Quiet Zones, and in frequency bands allocated to the radio astronomy service on a primary basis globally, from aggregate radio-frequency interference caused by non-geostationary-satellite orbit systems, in accordance with Resolution 681 (WRC‐23);
• 1.17 to consider regulatory provisions for receive-only space weather sensors and their protection in the Radio Regulations, taking into account the results of ITU Radiocommunication Sector studies, in accordance with Resolution 682 (WRC‐23);
• 1.18 to consider, based on the results of ITU Radiocommunication Sector studies, possible regulatory measures regarding the protection of the Earth exploration-satellite service (passive) and the radio astronomy service in certain frequency bands above 76 GHz from unwanted emissions of active services, in accordance with Resolution 712 (WRC-23);
• 1.19 to consider possible primary allocations in all Regions to the Earth exploration-satellite service (passive) in the frequency bands 4 200-4 400 MHz and 8 400-8 500 MHz, in accordance with Resolution 674 (WRC-23),
• 2 to examine the revised ITU Radiocommunication Sector Recommendations incorporated by reference in the Radio Regulations communicated by the Radiocommunication Assembly, in accordance with further resolves of Resolution 27 (Rev.WRC‐19), and to decide whether or not to update the corresponding references in the Radio Regulations, in accordance with the principles contained in resolves of that Resolution;
• 3 to consider such consequential changes and amendments to the Radio Regulations as may be necessitated by the decisions of the conference;
• 4 in accordance with Resolution 95 (Rev.WRC‐19), to review the resolutions and recommendations of previous conferences with a view to their possible revision, replacement or abrogation;
• 5 to review, and take appropriate action on, the Report from the Radiocommunication Assembly submitted in accordance with Nos. 135 and 136 of the ITU Convention;
• 6 to identify those items requiring urgent action by the radiocommunication study groups in preparation for the next world radiocommunication conference;
• 7 to consider possible changes, in response to Resolution 86 (Rev. Marrakesh, 2002) of the Plenipotentiary Conference, on advance publication, coordination, notification and recording procedures for frequency assignments pertaining to satellite networks, in accordance with Resolution 86 (Rev.WRC‐07), in order to facilitate the rational, efficient and economical use of radio frequencies and any associated orbits, including the geostationary-satellite orbit;
• 8 to consider and take appropriate action on requests from administrations to delete their country footnotes or to have their country name deleted from footnotes, if no longer required, taking into account Resolution 26 (Rev.WRC‐23);
• 9 to consider and approve the Report of the Director of the Radiocommunication Bureau, in accordance with Article 7 of the ITU Convention:
• 9.1 on the activities of the ITU Radiocommunication Sector since WRC‐231;
• 9.2 on any difficulties or inconsistencies encountered in the application of the Radio Regulations2; and
• 9.3 on action in response to Resolution 80 (Rev.WRC‐07);
• 10 to recommend to the ITU Council items for inclusion in the agenda for the next world radiocommunication conference, and items for the preliminary agenda of future conferences, in accordance with Article 7 of the ITU Convention and Resolution 804 (Rev.WRC‐23),​

WRC-31 preliminary agenda​​

• ​​2.1 to consider potential new allocations to the fixed, mobile, radiolocation, amateur, amateursatellite, radio astronomy, Earth exploration-satellite (passive and active) and space research (passive) services in the frequency ran​ge 275-325 GHz in the Table of Frequency Allocations of the Radio Regulations, with the consequential update of Nos. 5.149, 5.340, 5.564A and 5.565, in accordance with Resolution 721 (WRC-23);
• 2.2 [to consider the possible [frequency bands] for [non-beam and beam] wireless power transmission to avoid harmful interference to the radiocommunication services caused by wireless power transmission, in accordance with Resolution 910 (WRC-23)]; 
• 2.3 to consider the use of aeronautical and maritime earth stations in motion communicating with non-geostationary space stations in the fixed-satellite service (Earth-to-space) in the frequency band 12.75-13.25 GHz, in accordance with Resolution 133 (WRC-23);
• 2.4 to consider, based on the results of ITU Radiocommunication Sector studies, support for inter-satellite service allocations in the frequency bands 3 700-4 200 MHz and 5 925-6 425 MHz, and associated regulatory provisions, to enable links between non-geostationary orbit satellites and geostationary orbit satellites, in accordance with Resolution 683 (WRC-23);
• 2.5 to consider a possible primary allocation in the frequency bands [694-960 MHz, or parts thereof, in Region 1], 890-942 MHz, or parts thereof, in Region 2, and [3 400-3 700 MHz, or parts thereof, in Region 3] to the aeronautical mobile service for the use of International Mobile Telecommunications (IMT) user equipment in terrestrial IMT networks by non-safety applications, in accordance with Resolution 251 (Rev.WRC-23);
• 2.6 to consider the identification of the frequency bands [102-109.5 GHz, 151.5-164 GHz, 167- 174.8 GHz, 209-226 GHz and 252-275 GHz] for International Mobile Telecommunications, in accordance with Resolution 255 (WRC-23);
• 2.7 to consider improving the utilization of VHF maritime radiocommunication, in accordance with Resolution 363 (Rev.WRC-23);
• 2.8 to consider improving the utilization and channelization of maritime radiocommunication in the MF and HF bands, including potential revisions of Article 52 and Appendix 17, in accordance with Resolution 366 (WRC-23);
• 2.9 to consider possible allocations to the radionavigation-satellite service (space-to-Earth) in the frequency bands [5 030-5 150 MHz and 5 150-5 250 MHz] or parts thereof, in accordance with Resolution 684 (WRC-23);
• 2.10 to consider a possible new primary allocation to the Earth exploration-satellite service (Earthto-space) in the frequency band 22.55-23.15 GHz, in accordance with Resolution 664 (Rev.WRC-23);
• 2.11 to consider an upgrade of the secondary allocation to the Earth exploration-satellite service (space-to-Earth) in the frequency band [37.5-40.5 GHz] or possible new worldwide frequency allocations on a primary basis to the Earth exploration-satellite service (space-to-Earth) in certain frequency bands within the frequency range [40.5-52.4 GHz], in accordance with Resolution 685 (WRC-23);
• 2.12 to consider possible new allocations to the Earth exploration-satellite service (active) in the frequency bands [3 000-3 100 MHz] and [3 300-3 400 MHz] on a secondary basis, in accordance with Resolution 686 (WRC-23);
• 2.13 to consider studies on coexistence between spaceborne synthetic aperture radars operating in the Earth exploration-satellite service (active) and the radiodetermination service in the frequency band 9 200-10 400 MHz, with possible actions as appropriate, in accordance with Resolution 722 (WRC-23);
• ​2.14 to review spectrum use and needs of applications of broadcasting and mobile services and consider possible regulatory actions in the frequency band 470-694 MHz or parts thereof, in accordance with Resolution 235 (Rev.WRC-23);