Radio Regulations

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

1.12

WRC-27 · Agenda item 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)

Current WP 4C Res. 252 (WRC-23) › 1427–1432 MHz 1645.5–1646.5 MHz 1880–1920 MHz 2010–2025 MHz

Shared frequency bands

Bands this agenda item addresses jointly with other WRC-27 items (CPM Report Table 1). Click a band to open its spectrum page.

1427–1432 MHz 1645.5–1646.5 MHz 1880–1920 MHz

Also studied under: AI 1.13

2010–2025 MHz

Also studied under: AI 1.13 AI 1.14

At a glance Summary & background Regulatory Studies

At a glance Beta

Frequency band

1427–1432 MHz 1645.5–1646.5 MHz 1880–1920 MHz 2010–2025 MHz

Governing resolution

Res. 252 (WRC-23)

Responsible group WP 4C

Agenda-item type Technical

The band and its sensitive neighbours

Space operation

FIXED

MOBILE

MOBILE-SATELLITE

Earth exploration-satellite

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

SPACE OPERATION (Earth-to-space)	Primary
FIXED	Primary
MOBILE except aeronautical mobile	Primary
MOBILE	Primary
Mobile-satellite (Earth-to-space)	Primary

What's being studied — points to watch

Sharing with terrestrial IMT

All the candidate bands touch IMT: 1427–1432 MHz is IMT-identified globally (Res. 223), and 1880–1920 / 2010–2025 MHz are IMT-identified with deployed networks (Res. 212); new MSS links must not raise interference into them.

Existing MSS L-band

1645.5–1646.5 MHz is already MSS (Earth-to-space); adding systems must not crowd the incumbent mobile-satellite operations there.

Adjacent passive band

1400–1427 MHz, right below the first candidate band, is an all-emissions-prohibited passive band (EESS passive, radio astronomy, SRS passive — No. 5.340); unwanted emissions must stay out of it.

Low-data-rate footprint

The systems in scope carry no telephony and transmit data in bursts (Res. 252); they use many terminals and satellites, so the aggregate effect on incumbents, not the single link, sets the limits.

Four different bands

Each candidate band has a distinct set of services to protect, so a single sharing rule will not fit all four.

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

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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.