Methodology to determine the epfd downlink level corresponding to the loss of synchronization in geostationary fixed satellite service networks caused by interference from non-geostationary-satellite systems
The ITU Radiocommunication Assembly considering a) that loss of synchronization in a geostationary fixed-satellite service (GSO FSS) satellite link can be extremely disruptive to the underlying service being supported; b) that loss of synchronization will directly impact the availability of the supported service and that conservative satellite link budget design is dependent on the knowledge of the threshold at which loss of synchronization occurs; c) that the measure of unavailability of satellite networks is determined by the combined effects of equipment thresholds, interference and propagation effects; d) that the C/N level, at which loss of synchronization occurs, may be of the order of 1 to 4 dB lower than the required C/N level corresponding to the availability threshold (i.e. shortest term objective); e) that, in the case of GSO networks which are integrated in terrestrial networks, the network may shut down the link at a higher level than would cause the modem to lose synchronization; f) that World Radiocommunication Conference (Istanbul, 2000) (WRC-2000) adopted downlink equivalent power flux-density (epfd↓) limits, including operational limits, applicable to non-GSO systems in certain frequency bands; g) that GSO operators need to be able to identify climatological areas where the rain rate is such that links may be susceptible to interference peaks corresponding to the epfd↓operational limits, and to evaluate the susceptibility to loss of demodulator synchronization.