Balancing UHF broadcasting and mobile spectrum needs
Darko Ratkaj, Senior Project Manager, European Broadcasting Union (EBU)
Agenda item 1.5 of the upcoming World Radiocommunication Conference, WRC‑23, follows WRC‑07 and WRC‑12 decisions to add a primary mobile allocation in the 800 megahertz (MHz) and 700 MHz frequency bands, respectively. As a result, those bands have, in most countries, now been re-purposed from broadcasting to International Mobile Telecommunications (IMT).
Perhaps this is why WRC‑23 agenda item 1.5 is sometimes seen as the next “either-or” choice between terrestrial broadcasting and IMT.
Studies carried out in preparation for WRC‑23, however, reveal a much more diverse picture.
Services in the frequency band 470–960 MHz
The Radio Regulations include seven different radiocommunications services in the 470–960 MHz band:
- broadcasting — used for terrestrial television;
- mobile — used in different applications such as IMT, public protection and disaster relief (PPDR), the applications ancillary to broadcasting and programme-making (SAB/SAP), short-range devices, and railway and defence systems;
- radiolocation — used for wind-profiling radars;
- fixed-satellite service;
- mobile-satellite service; and
- aeronautical radio navigation.
Furthermore, in Region 1 (comprising Europe, Africa, the Commonwealth of Independent States, Mongolia, and the Middle East west of the Persian Gulf, including Iraq), as well as in Iran, this frequency band is governed by both the Radio Regulations and the Geneva 2006 Regional Agreement.
While the existing services and applications in the ultra-high-frequency (UHF) band may vary regarding their economic or public value, they are all important. Many are essential for a well-functioning society and governmental policies.
Some applications are used extensively with a mature ecosystem that would be difficult to replicate in other bands. Some depend on the specific physical properties of UHF, making it the only spectrum where they can operate.
Moreover, administrations clearly want to retain all existing allocations in the UHF band.
The studies by the ITU Radiocommunication Sector (ITU-R — one of three Sectors of the International Telecommunication Union) also revealed considerable differences in how spectrum is used in practice across Region 1, reflecting varying circumstances and priorities in different countries. This is true for all services in the UHF band and will likely remain so for the foreseeable future.
Some administrations are proposing to add a primary mobile allocation in the 470–694 MHz band, or part of it, to allow the introduction of IMT, public protection disaster relief (PPDR), or trunked ad-hoc mobile systems. But how would this proposal be implemented?
The need for coexistence
A significant majority of Region 1 administrations have said they require the full 470–694 MHz band for broadcasting in the future, allowing current sharing arrangements with radio astronomy and with services ancillary to broadcasting (SAB) and systems applications products (SAP) to continue. Therefore, additional mobile applications in this band would need to coexist with incumbent services.
However, coexistence requires a large geographical separation — up to hundreds of kilometres — between broadcasting and mobile stations. This is rather restrictive and inefficient.
Separation distances could be reduced only if the protection of one or both services were to be substantially lowered, which might be possible in some situations but is not generally applicable. This issue, identified in ITU radiocommunication studies, was confirmed by real interference cases reported when the 700 MHz and 800 MHz bands have been re-purposed from broadcasting to IMT.
Notwithstanding the ITU–R studies, administrations hold different views regarding future use of the UHF band. Some foresee a decreasing need for terrestrial broadcasting and wish to give more spectrum to the mobile service, while others consider existing mobile allocations in the UHF band to be sufficient.
Numerous administrations support investments in digital terrestrial television and SAB/SAP applications. In many European countries, current regulations below 694 MHz give priority to broadcasting and SAB/SAP until at least 2030. Therefore, any change would only be possible after that date.
The challenge of finding a balance
The challenge for WRC‑23 is to find a balance between these sometimes-contradictory objectives. The conference may decide to leave allocations in the 470–694 MHz band unchanged, or to add a primary mobile allocation.
Another proposal is to add a secondary mobile allocation at WRC‑23 and consider a possible upgrade eight years later, at WRC‑31.
Given the importance of the UHF band, administrations in Region 1 will undoubtedly continue to search for viable future arrangements. WRC‑23 may succeed in reconciling the diverging proposals, but it could just as likely leave a long-term solution to be found at a future conference.
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