This Report contains compatibility and sharing studies for wireless avionics intra-communication (WAIC) systems in the frequency band 4 200-4 400 MHz. The frequency band is allocated to the aeronautical radionavigation service (ARNS) for radio altimeters installed on board aircraft and for the associated transponders on the ground by Radio Regulations (RR) footnote No. 5.438. It may further be used by passive sensors in the Earth exploration-satellite service (EESS) and the space research service (SRS) on a secondary basis. It is also allocated to the fixed service (FS) on a secondary basis in one administration per RR footnote No. 5.439. Furthermore, the standard frequency and time signal-satellite service may be authorized to use the frequency 4 202 MHz for space-to-Earth transmissions. Such transmissions shall be confined within the frequency band 4 200-4 204 MHz, subject to agreement obtained under RR No. 9.21.
Studies involving the ARNS, focus on scenarios between different aircraft. Analyses involving compatibility between aeronautical systems installed on the same aircraft are under the purview of aircraft certification authorities.
As systems in the standard frequency and time signal-satellite service are authorised on a case by case basis in accordance with RR No. 9.21 coordination will be completed by individual Administrations. A general compatibility analysis is not required.