Radio Regulations

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

WRC Agenda Item › WRC-27 › AI 1.11
AI

1.11

WRC-27 · Agenda item 1.11

to consider the technical and operational issues, and regulatory provisions, for space-to-space links among non-geostationary and geostationary satellites in the frequency bands 1 518-1 544 MHz, 1 545-1 559 MHz, 1 610-1 645.5 MHz, 1 646.5-1 660 MHz, 1 670-1 675 MHz and 2 483.5-2 500 MHz allocated to the mobile-satellite service, in accordance with Resolution 249 (Rev.WRC-23)

Current WP 4C Res. 249 (Rev.WRC-23) › 1518–1525 MHz 1518–1544 MHz 1525–1544 MHz 1545–1559 MHz 1610–1626.5 MHz 1610–1645.5 MHz 1613.8–1626.5 MHz 1626.5–1645.5 MHz 1646.5–1660 MHz 1670–1675 MHz 2483.5–2500 MHz

Shared frequency bands

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

1518–1544 MHz 1545–1559 MHz 1610–1645.5 MHz 1646.5–1660 MHz 1670–1675 MHz
Also studied under: AI 1.13
2483.5–2500 MHz
Also studied under: AI 1.13 AI 1.15
At a glance Summary & background Regulatory Studies

At a glance Beta

Frequency band
1518–1525 MHz 1518–1544 MHz 1525–1544 MHz 1545–1559 MHz 1610–1626.5 MHz 1610–1645.5 MHz 1613.8–1626.5 MHz 1626.5–1645.5 MHz 1646.5–1660 MHz 1670–1675 MHz 2483.5–2500 MHz
Governing resolution
Res. 249 (Rev.WRC-23)
Responsible group WP 4C
Agenda-item type Technical

The band and its sensitive neighbours

1518–1544 MHz 1646.5–1660 MHz 2483.5–2500 MHz Radionavigation-satellite 1559–1610 Radio astronomy 1610.6–1613.8 Radio astronomy 1660–1670 1500 1544 1610 1646.5 2483.5 2520 MHz
FIXED
MOBILE
MOBILE-SATELLITE
Space operation
RADIONAVIGATION
Radio astronomy
Radiodetermination satellite
METEOROLOGICAL AIDS
Meteorological satellite
Radiolocation
Radionavigation-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

MOBILE-SATELLITE Primary the bands in scope
Radionavigation-satellite Primary adjacent — GNSS, 1559–1610 MHz
Radio astronomy Primary 1610.6–1613.8 (in-band) / 1660–1670 MHz; No. 5.149

What's being studied — points to watch

Protecting GNSS

The adjacent radionavigation-satellite band (GPS/Galileo/BeiDou) is safety-of-life; space-to-space links must not raise interference into it.

Incumbent MSS user links

Space-to-space stations may neither cause harmful interference to, nor claim protection from, the existing MSS user links — with GMDSS distress and aeronautical (R) priorities expressly preserved (Res. 249).

Radio astronomy

Radio astronomy is primary at 1610.6–1613.8 MHz (inside a scope band) and 1660–1670 MHz; No. 5.149 applies and the faint-signal observations need protection.

Same direction only

Space-to-space links may only operate in the same direction as the existing MSS allocations, via higher-altitude non-GSO or GSO relays (Res. 249).

Preparation timeline

  1. Dec 2023 WRC-23 agenda adopted
  2. Dec 2023 CPM 27-1 studies allocated
  3. ITU-R studies 2026
  4. ITU-R studies 2027
  5. 5–15 Apr 2027 CPM 27-2 final report
  6. RTO Prep meetings 2027
  7. 11–15 Oct 2027 RA-27
  8. 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.