Radio Regulations

Source: the Radio Regulations published by the International Telecommunication Union (ITU).

WRC Agenda Item › WRC-27 › AI 1.4

1.4

WRC-27 · Agenda item 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)

Current WP 4A Res. 726 (WRC-23) › 17.3–17.7 GHz 17.3–17.8 GHz 17.7–17.8 GHz

At a glance Summary & background Regulatory Studies

At a glance Beta

Frequency band

17.3–17.7 GHz 17.3–17.8 GHz 17.7–17.8 GHz

Governing resolution

Res. 726 (WRC-23)

Responsible group WP 4A

Agenda-item type Technical

The band and its sensitive neighbours

Fixed satellite

BROADCASTING-SATELLITE

FIXED

MOBILE

Blocks group a service with its direction and mode variants; the table names each allocation as the Radio Regulations name it.

Current framework

Services in this band

FIXED-SATELLITE (Earth-to-space) (space-to-Earth)	Primary Regions 1, 2 only
BROADCASTING-SATELLITE	Primary Region 2 only
FIXED-SATELLITE (Earth-to-space)	Primary Region 3 only
FIXED	Primary
FIXED-SATELLITE (space-to-Earth) (Earth-to-space)	Primary
MOBILE	Primary Regions 1, 3 only
Radiolocation	Secondary

Key figures in today's rules

Parameter	GSO	Non-GSO
Region 3 today 17.3–18.1 GHz (No. 5.516)	FSS Earth-to-space only
EPFD protecting GSO networks non-GSO FSS (space-to-Earth), 17.3–17.7 GHz — Region 2	Article 22, Tables 22-1B / 22-3 / 22-4B
Scope of the R2 limits at WRC-27	reference for Regions 1 & 3 — no change intended for Region 2 (Res. 726)

Reference figures, verified against the Radio Regulations.

What's being studied — points to watch

New downlink in Region 3

Adding space-to-Earth in Region 3 (today uplink-only under No. 5.516) must not degrade existing primary services in and beside the band — Res. 726 singles out the BSS feeder links of Appendix 30A.

Harmonised EPFD limits

Extend the Region 2 EPFD framework so non-GSO downlinks protect GSO networks consistently across Regions 1 and 3.

GSO protection

Non-GSO constellations sharing with GSO networks is the core sharing case the EPFD limits must bound.

Regional alignment vs burden

Closing the regional inconsistency has to be weighed against the added coordination it creates.

Preparation timeline

Dec 2023 WRC-23 agenda adopted

Dec 2023 WRC-23 agenda adopted
Dec 2023 CPM 27-1 studies allocated

Dec 2023 CPM 27-1 studies allocated
ITU-R studies 2026

ITU-R studies 2026
ITU-R studies 2027

ITU-R studies 2027
5–15 Apr 2027 CPM 27-2 final report

5–15 Apr 2027 CPM 27-2 final report
RTO Prep meetings 2027

RTO Prep meetings 2027
11–15 Oct 2027 RA-27

11–15 Oct 2027 RA-27
18 Oct–12 Nov 2027 WRC-27

18 Oct–12 Nov 2027 WRC-27

Dec 2023 WRC-23 agenda adopted
Dec 2023 CPM 27-1 studies allocated
ITU-R studies 2026
ITU-R studies 2027
5–15 Apr 2027 CPM 27-2 final report
RTO Prep meetings 2027
11–15 Oct 2027 RA-27
18 Oct–12 Nov 2027 WRC-27

Spotted an inaccuracy in this analysis? Please let us know via the contact form →

Source: ITU Radio Regulations, editions of 2008, 2012, 2016, 2020 and 2024. The English, French and Spanish texts are each taken from the official edition in that language, not translated from one another. Sources and citation.