Preliminary estimation of mutual interference between fixed satellite service systems

The method of preliminary interference estimation according to the International Radio Consultative Committee regulations for geostationary satellite networks sharing the same frequency band is applicable to any system regardless of signal form and modulation type, as well as regardless of the exact carrier frequency. A preliminary estimation involves determining the relative increment of equivalent noise temperature which is produced in one satellite channel by interference signals from another, assuming that an interference signal is equivalent to thermal noise of uniform spectral power density equal to the maximum disclosed in the application for license. Such preliminary estimates are based on fundamental relations for the useful signal in the presence of thermal noise with the intermodulation component of noise taken into account. These relations are derived here for satellite telephone channels in a system with frequency modulation of analog signals and with frequency division multiplex, in a system with phase keying of digital signals and time division multiplex, in a one channel per carrier system with pulse code modulation and phase keying.