An overall channel model for the mobile user objective system including ionospheric scintillation and terrestrial multipath

Using a channel impulse response function formalism, an overall channel model which combines ionospheric scintillation fading and terrestrial multipath effects has been developed for the mobile user objective system (MUOS). For ionospheric scintillation fading we construct a channel impulse response function using a mutual coherence function. For terrestrial multipath we use a channel impulse response function based on a tapped-delay line model. We solve the combined model numerically using the Naval Research Laboratory Impulse Response Function Simulator code (NCIRFS) for several modulation waveforms for both frequency selective and frequency nonselective fading conditions. We compute the delay spread for a simulated ground terminal in an urban and maritime fading environment. For an urban or maritime scintillation environment we find that the delay spread is a multiplicative combination of both multipath and ionospheric scintillation fading and can extend over several modulation periods. We present results for several waveforms and for combinations of fading and multipath environments.