WRC-23: Safeguarding high-quality broadcasting services

By Yukihiro Nishida, Chairman, ITU-R Study Group 6

Study Group 6 in the ITU Radiocommunication Sector (ITU-R – one of three Sectors of the International Telecommunication Union) is responsible for the international standardization of broadcasting services, covering programme production, international exchange, quality assessment, and delivery to the general public. This includes spectrum management for the protection of broadcasting services worldwide.

Recommendations and reports produced by the study group address the need for global, harmonized solutions to improve the interoperability, accessibility, and environmental sustainability of broadcasting technologies. This crucial ITU-R guidance allows the industry to innovate and guarantees the quality of experience that the audience expects in an ever-changing information and communication technology environment.

These activities have never been so important as they are now to support current and future broadcasting services.

Continuously evolving

Broadcasting continuously evolves to better serve the public, and broadcasters have always been expected to provide the best service based on state‑of‑the-art technologies.

ITU-R first standardized digital terrestrial television broadcasting (DTTB) systems about 25 years ago. DTTB first- and second-generation systems, and more recently 5G broadcasting systems, are all specified in ITU-R standards, known as “Recommendations”.

Frequency bands – ranging from low frequency (LF) to ultra-high frequency (UHF) – are assigned and used worldwide for radio, television, and multimedia terrestrial broadcasting. Although no additional spectrum has been allocated to broadcasting for years, the demand for more and better services continues to grow.

Parts of the frequency bands allocated to broadcasting remain under threat from competing uses, including new and emerging technologies and services. Several agenda items for the upcoming World Radiocommunication Conference, WRC‑23, are highly relevant to future terrestrial broadcasting services in the UHF, very high frequency (VHF), and high frequency (HF) bands.

UHF band

Broadcasting has relied for many years on globally harmonized use of the UHF band for the delivery of terrestrial television. Terrestrial TV will remain vital for the distribution of public service media in many countries, with the transition from analogue to digital broadcasting enabling more efficient spectrum utilization for terrestrial broadcast services.

Along with ensuring universal access to public service media, improved spectrum efficiency has provided a digital dividend, allowing the release of part of the UHF band to mobile services. The “digital dividend” is defined as the upper segment of the UHF band, lying between 694/698 megahertz (MHz) and 862 MHz. 

The UHF band is also vital for services ancillary to broadcasting and programme-making. These include the daily use of radio microphones, talkback systems and in-ear monitors – essential tools for audio content production.

Agenda items on the table for discussion at WRC‑23 include various issues with implications for spectrum allocation for broadcasting.

Agenda item 1.4 – To consider, in accordance with Resolution 247 (WRC‑19), the use of high-altitude platform stations as IMT base stations (HIBS) in the mobile service in certain frequency bands below 2.7 gigahertz (GHz) already identified for international mobile telecommunications (IMT), on a global or regional level

The allocation to the broadcasting service in the 694‑862 MHz band for parts of Regions 1 and 3 continues to be subject to the GE06 Agreement regulating the use of terrestrial services. In addition, the primary allocation to the broadcasting service in the 862‑960 MHz band in the African Broadcasting Area remains subject to ITU Radio Regulations provision No. 5.322.

Country regulatory variations found in the Radio Regulations may also apply to existing arrangements for broadcasting services in the 694‑960 MHz band. Both existing and prospective broadcasting services, therefore, need to be shielded from any possible interference from HIBS in that frequency band.

Agenda item 1.5 – To review the spectrum use and spectrum needs of existing services in the frequency band 470‑960 MHz in Region 1 and consider possible regulatory actions in the frequency band 470‑694 MHz in Region 1 on the basis of the review in accordance with Resolution 235 (WRC-15)

The use of radio spectrum varies considerably across Region 1 for all existing services.

Parts of the frequency band 470‑960 MHz are currently allocated for broadcasting, mobile (except aeronautical mobile), radio astronomy, radiolocation, fixed services, mobile-satellite (except aeronautical mobile-satellite (radiocommunication)), and aeronautical radionavigation uses.

Some administrations in Region 1 indicate that the amount of spectrum in the 470‑694 MHz band currently allocated for the broadcasting service is sufficient and necessary and that they will continue with current usage. Others have expressed interest in providing additional spectrum for international mobile telecommunications (IMT), public protection and disaster relief, and non-IMT trunked ad-hoc land mobile systems in the band below 694 MHz.

Co-channel sharing and compatibility studies have examined the impact of IMT base stations and user terminals on digital terrestrial television broadcasting reception. The results, however, vary widely, depending on assumptions in the studies and showed different separation distances required to comply with the assumed protection criteria.

Some study results suggest that coexistence between IMT systems and broadcasting systems is feasible, while others show difficulties arising from spectrum sharing, particularly where large separation distances – ranging from tens to hundreds of kilometres – are required to protect DTTB from possible interference by IMT base stations and vice-versa.

VHF band

Agenda item 1.12 – To conduct, and complete in time for WRC‑23, studies for a possible new secondary allocation to the Earth exploration-satellite (active) service for spaceborne radar sounders within the range of frequencies around 45 MHz, taking into account the protection of incumbent services, including in adjacent bands, in accordance with Resolution 656 (Rev. WRC‑19)

Frequency allocations for existing broadcasting services are found in the range 47‑68 MHz in the Radio Regulations, which also include some country regulatory variations.

The frequency allocation to the broadcasting service in Region 1 for the 47‑68 MHz band continues to be subject to the Stockholm Frequency Plan of 1961 (ST61) and the Regional Agreement relating to the Planning of VHF/UHF Television Broadcasting in the African Broadcasting Area and Neighbouring Countries, Geneva, 1989 (GE89), both revised in Geneva, Switzerland, in 2006.

HF band

Agenda item 1.9 – To review Appendix 27 of the Radio Regulations and consider appropriate regulatory actions and updates based on ITU‑R studies, in order to accommodate digital technologies for commercial aviation safety‑of‑life applications in existing HF bands allocated to the aeronautical mobile (route) service and ensure coexistence of current HF systems alongside modernized HF systems, in accordance with Resolution 429 (WRC‑19)

Possible out-of-band emissions from aeronautical mobile (radiocommunication (R)) stations may cause interference to high-frequency broadcasting (HFBC). In particular, the aeronautical mobile (R) ranges of 3 400 3 500 kilohertz (kHz) and 17 900-17 970 kHz are adjacent to the HFBC bands 3 230-3 400 kHz and 17 550-17 900 kHz, respectively.

HFBC transmissions require protection from any possible out-of-band interference from aeronautical mobile (R) stations operating near HFBC bands and should not be subject to additional constraints from such stations.

World Radiocommunication Conference resolutions mentioned in this article:

• Resolution 247 (WRC-19) – Facilitating mobile connectivity in certain frequency bands below 2.7 GHz using high-altitude platform stations as IMT base stations

• Resolution 235 (WRC-15) – Review of the spectrum use of the frequency band 470‑960 MHz in Region 1

• Resolution 656 (Rev. WRC-19) – Possible secondary allocation to the Earth exploration-satellite service (active) for spaceborne radar sounders in the range of frequencies around 45 MHz

• Resolution 429 (WRC‑19) – Consideration of regulatory provisions for updating Appendix 27 of the Radio Regulations in support of aeronautical HF modernization

This article first appeared in the ITU News Magazine, which outlines key technical and regional perspectives on topics to be discussed at the World Radiocommunication Conference (WRC-23) taking place in Dubai, UAE, between 20 November and 15 December 2023.

Header image credit: Tiecoura Ndaou