Report on ITU Radiocommunication Assembly 2023 (RA-23) and World Radiocommunication Conference 2023 (WRC-23)

Masayoshi Tachiki, Hisako Tanida and Hiroyuki Atarashi
Spectrum Planning Office

Abstract
The Radiocommunication Assembly 2023 (RA-23) and the World Radiocommunication Conference 2023 (WRC-23) were held in Dubai, UAE from November 13 to 17, 2023 and from November 20 to December 15, 2023, respectively. RA-23 determined ITU-R Resolutions and ITU-R Recommendations, while WRC-23 determined the amendments to the ITU Radio Regulations, including the identification of new frequency bands for IMT. The main outcomes of these deliberations and meetings are summarized in this report.

01. Introduction

  • The International Telecommunication Union (ITU) is the United Nations ...

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    The International Telecommunication Union (ITU) is the United Nations specialized agency for managing the international standards and regulations concerning telecommunications and radiocommunications. The ITU Radiocommunication sector (ITU-R) is responsible for global management of the radio-frequency spectrum and satellite orbits, which are limited resources, and development and standardization for regulations regarding radiocommunications. As part of ITU-R activities, the Radiocommunication Assembly (RA) and the World Radiocommunication Conference (WRC), which are usually held every three to four years, are important meetings attended by a large number of delegates from telecommunications administrations of ITU member states (193 in total).

    From November to December, 2023, about 500 delegates from 116 countries attended the Radiocommunication Assembly (RA-23) and about 3,900 delegates from 163 countries attended the World Radiocommunication Conference (WRC-23)—both held in Dubai, UAE. The major outcomes of the deliberations at RA-23 and WRC-23 are summarized in this article.

    • 02. Content and Results of Deliberations at RA-23

  • The RA is the general assembly of ITU-R that approves ITU-R Resolutions, ...

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    The RA is the general assembly of ITU-R that approves ITU-R Resolutions, which define working methods, and approves ITU-R Recommendations and ITU-R Questions. Moreover, as part of the review of ITU-R’s study structure, the RA also reviews the composition of Study Groups (SGs) as appropriate and appoints chairs and vice-chairs.

    2.1 Approval of ITU-R Resolutions and Recommendations

    Regarding ITU-R Resolutions, RA-23 approved four new resolutions, the revision of 26 existing resolutions, and the deletion of four existing resolutions.

    The working methods of RAs, SGs, and related working parties are defined in ITU-R Resolution 1. RA-23 reviewed Resolution 1 and newly established the term of office for the chairs of Working Parties under SGs by stipulating two terms in principle and a maximum of three terms in unavoidable circumstances.

    ITU-R Resolution 56, which defines the name “International Mobile Telecommunications” (IMT)*1, was revised, and the new name “IMT-2030” was added to cover the so-called 6th Generation mobile communications system (6G). IMT-2030 thereby became an official name used by the ITU-R. In addition, ITU-R Resolution 65, a resolution on principles for future IMT development processes adopted by the ITU-R, was revised, and the addition of development processes for IMT-2030 was approved. A new resolution calling for strengthening and speeding-up of efforts towards gender equality in ITU-R activities, ITU-R Resolution 72, was also approved.

    ITU-R Recommendations are formally approved by the ITU-R, usually after adoption by each SG, through a postal ballot by ITU member states. However, if it is determined that approval by the RA is appropriate, it is possible for the RA to approve them. In September 2023, ITU-R Recommendation M.2160 (which outlines the framework and objectives of IMT-2030) was adopted by SG 5, which is in charge of terrestrial services, and it was waiting formal approval by postal ballot from ITU member states by the December deadline. However, since ITU-R Resolutions 56 and 65 refer to ITU-R Recommendation M.2160, in conjunction with the approval of these ITU-R Resolutions, ITU-R Recommendation M.2160 was also approved.

    2.2 Appointment of Chairs and Vice-Chairs of ITU-R SGs

    At RA-23, the chairs of SG 1, which is responsible for spectrum management, and SG 4, which is responsible for satellite services, were reappointed for their second term.

    Moreover, the terms of the chairs of SG 3 (radiowave propagation), SG 5 (terrestrial services), SG 6 (broadcasting services), and SG 7 (science services) had expired after two terms, so new chairs were appointed. Among those persons, Yukihiro Nishida (NHK, Japan) was appointed the chair of SG 6.

    Vice-chairs of SGs were approved at RA-23 as vice-chair candidates. The vice-chair of SG 4, Takahiro Kono (SKY Perfect JSAT) from Japan, was approved as a vice-chair candidate for a second term following his previous term. Hiroyuki Atarashi (one of the authors) completed his second term as the vice-chair of SG 5, and Satoshi Imata (KDDI) and Satoshi Oode (NHK) were approved as vice-chair candidates. Normally, vice-chairs are formally appointed at the RA, but the vice-chair candidates proposed at RA-23 will be formally appointed at each future SG meeting.

    1. IMT: A generic term for international mobile telecommunications systems, encompassing IMT-2000 (3G), IMT-Advanced (4G/LTE), IMT-2020 (5G), etc., standardized at ITU.

    • 03. Content and Results of Deliberations at WRC-23

  • The WRC is a meeting that deliberates on the revision of the ITU’s ...

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    The WRC is a meeting that deliberates on the revision of the ITU’s Radio Regulations (RR)*2, and its agenda is determined at the previous WRC. After agenda items of the next WRC are decided, during the three to four years until that WRC, the working groups of the SGs at the ITU-R conduct the studies necessary for discussion at the next WRC, and at the next WRC, the results of those studies are deliberated. For instance, WRC-23 discussed about 30 agenda items set at WRC-19.

    3.1 Identification of Additional Frequencies for IMT (WRC-23 Agenda Item 1.2)

    Following WRC-19, WRC-23 discussed the possible identification of additional frequencies for IMT systems under RR as WRC-23 Agenda Item 1.2. WRC-19 Agenda Item 1.13 considered identification of the frequency bands above 24.25 GHz, and WRC-23 Agenda Item 1.2 considered identification of the frequency bands 3,300 to 3,400 MHz (Regions 1 and 2), 3,600 to 3,800 MHz (Region 2), 6,425 to 7,025 MHz (Region 1), 7,025 to 7,125 MHz (all regions), and 10.0 to 10.5 GHz (Region 2). Region 1 includes Europe, the Middle East, Africa, and the former Soviet Union, Region 2 includes the Americas, and Region 3 includes the Asia-Pacific region including Japan.

    The most-difficult discussions on this agenda was the frequency bands of 6,425 to 7,025 MHz and 7,025 to 7,125 MHz. After deliberations, 7,025 to 7,125 MHz became the frequency band identified for IMT in Regions 1 and 3 and in some countries in Region 2 (Table 1). Moreover, 6,425 to 7,025 MHz was identified as the frequency band for IMT in the entire Region 1 as well as some countries in Regions 2 and 3.

    The scope of Agenda Item 1.2, which was agreed on at WRC-19, was that the IMT identification of the 6,425 to 7,025-MHz band would be considered for Region 1 only. However, at WRC-23, some countries in Regions 2 and 3 proposed including IMT identification of that band. Whether to approve such proposals as part of the scope of Agenda 1.2 was subject to major debate, and many members raised concerns against identifying that frequency band for IMT in those regions on the grounds that the ITU-R had not sufficiently studied such identification. In the end, however, it was agreed to identify the frequency band of 6,425 to 7,025 MHz for IMT for Mexico and Brazil (Region 2) and for Cambodia, Laos, and the Maldives (Region 3).

    A new regulation to limit the transmission power of IMT radio stations using the 6,425 to 7,125-MHz band was added to protect fixed-satellite stations that share this frequency band. It regulates the transmission power of IMT stations by setting an upper limit of Equivalent Isotropically Radiated Power (EIRP)*3 per elevation angle. Although they had diverging views, IMT proponents and countries advocating protection of satellite services extensively discussed this regulation and made proposals concerning the upper limit of EIRP and, eventually, the countries involved in those discussions reached a certain consensus.

    As for IMT identification of other frequency bands to be considered in Agenda Item 1.2, the number of countries in Region 1 identifying the 3,300 to 3,400-MHz band for IMT was increased, while identification of that band was expanded to cover the entire Region 2. IMT identification of the 3,600 to 3,700-MHz band was extended to the entire Region 2, and IMT identification of the 3,700 to 3,800-MHz band was granted to certain countries in Region 2. In addition, IMT identification of the 10 to 10.5-GHz band was granted to certain countries in Region 2.

    Table 1 Results of IMT identification of frequency bands

    3.2 Other Related Agenda Items (WRC-23 Agenda Items 1.3 and 1.5)

    WRC-23 Agenda Item 1.3 examines the primary allocation*4 of the 3,600 to 3,800-MHz band to mobile services in Region 1 and WRC-23 Agenda Item 1.5 reviews the use and demand for frequencies for existing services in the 470 to 960-MHz band in Region 1 and considers regulatory provisions based on the results of that review. Although IMT identification was not in the scope of these agenda items, some countries proposed to include IMT identification in these agenda items, and that proposal was discussed.

    As a result of the discussion on Agenda Item 1.3, in line with the primary allocation of the 3,600 to 3,800-MHz band for mobile services (except aeronautical mobile services) in Region 1, the 3,600 to 3,700-MHz band was newly identified for IMT in six countries in Region 1, and the 3,600 to 3,800-MHz band was newly identified for IMT in 59 countries in Region 1. Moreover, as a result of discussions on Agenda Item 1.5, the 614 to 694-MHz band was newly identified for IMT in 11 countries in Region 1. The specific status of IMT based on the results of the above-described discussions on Agenda Items 1.2, 1.3, and 1.5 are summarized in Table 1.

    3.3 Consideration of HIBS Usage (WRC-23 Agenda Item 1.4)

    WRC-23 Agenda Item 1.4 considers the use of high-altitude platform station as an IMT Base Station (HIBS)*5 operating in the frequency bands identified for IMT below 2.7 GHz. As a result of the deliberations on that Item, the frequencies available for HIBS were expanded, while a resolution that stipulated the conditions under which HIBS operation will not adversely affect existing services was agreed. The resolution stipulated that a HIBS has to be operated at an altitude of 18 to 25 km and that notification to the ITU-R is required when operating a HIBS. Furthermore, for the purpose of protecting existing systems (including IMT) operated on the ground, upper limits for power flux density*6 emitted from a HIBS were specified for each system.

    The frequencies identified for HIBS are shown in Figure 1. While most of the candidate frequency bands considered by WRC-23 were identified for HIBS, in Region 3, the 700 to 900-MHz band is available for use by HIBS in some countries. Moreover, as a result of coordination with neighboring countries that were concerned about interference from HIBS, eight countries (including Japan) have been identified for HIBS using certain frequencies in the 700 to 900-MHz band.

    Figure 1 Frequencies identified for HIBS

    3.4 New Agenda Items for WRC-27 (Identification of Frequencies for IMT, WRC-27 Agenda Item 1.7)

    At WRC-23, possible identification of additional frequencies for IMT was discussed on the WRC-27 agenda. Focusing on the 7 to 24-GHz band, which has not been studied at previous WRCs, some members proposed those frequencies as candidates for possible IMT identification. Although some countries opposed the idea of establishing new IMT frequency-band identification on the WRC-27 agenda from the perspective of protecting satellite services, overall, discussions progressed toward setting an agenda for WRC-27 that considers identification of additional frequencies for IMT. However, views on the specific candidate frequency bands varied from country to country and region to region. The status of the proposed candidate frequency bands for IMT identification at WRC-27 are shown in Figure 2.

    The WRC accepted regional common proposals for candidate frequency bands from the Regional Commonwealth in the Field of Communications (RCC), the Arab Spectrum Management Group (ASMG), and the Inter-American Telecommunications Commission (CITEL), which are regional organizations in the former Soviet Union, the Middle East, and the Americas, respectively. On the contrary, the Asia-Pacific Telecommunity (APT), the regional organization for the Asia-Pacific region (including Japan), was unable to reach consensus on candidate frequency bands and was thus unable to make a regional common proposal. Under those circumstances, Japan independently proposed the 12.75 to 12.95-GHz band as a candidate frequency band for IMT and supported the 14.9 to 15.2-GHz band during deliberations at WRC-23.

    As shown in Fig. 2, the proposed candidate frequency bands were so diverse that it was deemed difficult to reach a common view. Therefore, during WRC-23, the candidate frequency bands were narrowed down through discussions at inter-regional meetings among the representatives of the aforementioned regional organizations, the European regional organization, the European Conference of Postal and Telecommunications Administrations (CEPT), and the African regional organization, the African Telecommunications Union (ATU). Many countries expressed dissatisfaction with the narrowing down of the candidate frequency bands by a limited number of attendees at those meetings; nevertheless, it was finally decided to adopt the results of the inter-regional meetings because it was not practical under time constraints to discuss each of the candidate frequency bands in one large meeting in which many countries have different positions.

    Priority was given to proposals submitted by regional organizations, and the candidate frequency bands were the 4,400 to 4,800-MHz band (or part thereof) for Regions 1 and 3, the 7,125 to 8,400-MHz band (or part thereof) for Regions 2 and 3, the 7,125 to 7,250-MHz band and the 7,750 to 8,400-MHz band (or part thereof) for Region 1, and the 14.8 to 15.35-GHz band for all regions.

    The 12.75 to 12.95-GHz band proposed by Japan was not selected as a candidate frequency band because the proposal faced much opposition and gained little support because it is widely used for international satellite operations. However, the 14.9 to 15.2-GHz band (which was additionally supported by Japan) was adopted. The relationships between the frequency bands identified for IMT at WRC-23 and the candidate frequency bands for IMT identification to be considered at WRC-27 are shown graphically in Figure 3.

    Figure 2 Proposed candidate frequency bands for IMT identification, Figure 3 Frequency bands identified for IMT at WRC-23 and candidate frequency bands for IMT identification at WRC-27

    3.5 New Agenda Item (Direct Communication between Terrestrial IMT User Devices and Equipment and Satellites)

    The “Non-Terrestrial Network” (NTN)*7 has been attracting attention. At WRC-23, direct communication between satellites and IMT user equipment was agreed. Moreover, ITU-R agreed on studies to consider frequency allocation and various operating conditions for mobile satellite services as an agenda item for WRC-27. Japan proposed direct communication between non-geostationary satellites and IMT user devices and equipment at frequencies below 2.2 GHz as the target of the consideration at WRC-27; however, some countries and regions promoting satellite operations made various other proposals, which included those for such communication at frequencies below 5 GHz or below 3 GHz. As a result of discussions, in consideration of frequencies identified for terrestrial IMT systems, it was decided that the frequency range for geostationary and non-geostationary satellites should be 2.7 GHz or lower.

    In addition, the role of direct communication between IMT user equipment and satellites is to complement the area covered by terrestrial IMT systems, and it was decided to consider operations and regulations that will not cause interference with existing services, including those using adjacent frequencies.

    1. RR: A collection of rules governing the use of radiowaves. The content of agreements reached at the WRC is reflected in the RR. As a diplomatic document that forms part of the International Telecommunication Regulations, it is binding on countries that have ratified the treaty.
    2. EIRP: Transmission power at the reference point in radiowave radiation space.
    3. Primary allocation: Allocation of frequencies to a primary service in the ITU Radio Regulations. Services to which frequencies are allocated are classified as primary or secondary services. Primary services can be protected from harmful interference from other primary services or secondary services. Conversely, secondary services cannot cause harmful interference to the operation of primary services nor claim protection from primary-service interference.
    4. HIBS: A high-altitude platform station that serves as a base station for IMT. Located in the upper atmosphere, it is in a fixed position relative to the Earth.
    5. Power flux density: Power intensity of a radiowave passing through a unit area.
    6. NTN: A network that extends the communications area to diverse locations (including the air, sea, and space) by using non-terrestrial media (such as satellites and high-altitude platform stations) without limiting the coverage area to land.

    • 04. Conclusion

  • At WRC-23, several new frequency bands were identified for IMT under ITU RRs, ...

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    At WRC-23, several new frequency bands were identified for IMT under ITU RRs, and it was decided to consider additional studies for frequency bands for possible identification of IMT at WRC-27. This decision was the fourth time since WRC-15 to establish WRC agenda items for possible identification of IMT. However, during the discussions of new agenda items for WRC-27, selected members from each regional organization decided to narrow down the candidate frequency bands to be considered as agenda items for identification of IMT, and the results of the discussions were approved. Although some member states raised concerns about this decision process, the reality is that as the size of meetings grows and discussions become more complex, it is inevitable that the same decision process may continue at future WRCs. Under these circumstances, it will be difficult for a single member state or a small number of member states to pass a joint proposal at the WRC; it is thus important that Japan further increases its presence at in the APT region while building cooperative relationships with other Asia-Pacific countries.

    At WRC-23, more frequency bands identified for HIBS were approved, and at WRC-27, possible use of direct communication between IMT user equipment and mobile satellite stations will be discussed as Agenda Item 1.13. These activities demonstrate that as the development of NTN-related technologies progresses, discussions on the frequencies required for implementing those technologies are becoming necessary, and the role of the ITU-R is becoming increasingly important. Since the use of NTNs for IMT differs from that of conventional IMT systems, the ITU-R study for WRC-27 Agenda Item 1.13 will be carried out by Working Party 4C (under SG 4, which is responsible for mobile satellite services), while Working Party 5D (under SG 5, which is responsible for terrestrial IMT systems) will provide the necessary information to support the study by Working Party 4C. With this background in mind, NTT DOCOMO will continue to actively participate in the ITU-R studies and APT conference preparatory groups for WRC-27 while collecting information and making various proposals for WRC-27.

VOL.26 NO.1

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