Communication availability enhancement of hybrid systems through exploitation of media diversity: evaluation of HF and satellite communication impairment mechanisms

Diversity schemes have been developed to enable HF systems to recover from media-specific disturbances, and fade margins are typically applied to ameliorate the effects of fading on satellite communication links. In this paper we describe a hybrid system concept comprised of an L-band Satcom and a terrestrial HF communication system. We examine the synergy which exists between these media in terms of composite communication connectivity, a synergy which may derive from an independence of failure mechanisms. In the analysis we make use of two climatological codes for estimating performance or impairment: WBMOD, a Satcom scintillation prediction code, and VOACAP, a well-known HF communication prediction model.