What is frequency coordination?
Frequency coordination is the technical and regulatory process by which satellite operators and their national licensing authorities ensure that the radio signals from a new satellite network do not cause harmful interference to previously registered satellite networks, and vice versa. It is mandated by ITU Radio Regulations and is a prerequisite for a network's frequency assignments to be recognised internationally in the Master International Frequency Register (MIFR).
How the process works
When a national administration submits a satellite network filing to the ITU, all other administrations operating networks in the same frequency band and orbit have the right to require coordination. The requesting administration must calculate interference levels (typically expressed as percentage increase in noise temperature, or C/I ratios) for all affected networks. If the calculated interference exceeds regulatory thresholds, the two administrations — or their operators — must negotiate technical compromises: adjusting power levels, changing polarisation, modifying beam patterns, or coordinating geographic exclusion zones.
GEO vs. NGSO coordination
GEO coordination focuses on the orbital arc — adjacent orbital positions sharing the same frequency band and footprint. The ITU's 2° orbit spacing rule for the C and Ku-band GEO arcs has governed satellite neighbourly rights for decades. NGSO (LEO and MEO) coordination is more complex: a NGSO constellation's thousands of satellites constantly move through different positions relative to GEO satellites, creating interference that varies continuously in geometry. NGSO operators must demonstrate compliance with GEO protection criteria across all geometries — a massive computational challenge addressed through statistical analysis and aggregate interference models.