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

Abstract

Using a channel impulse responsehnction formalism, an overall channel model which combines ionospheric scintillation fading and terrestrial multipath efects has been developed for the Mobile User Objective System (W O S). For ionospheric scintillation fading we construct a channel impulse response function using a mutual coherence hnction. For terrestrial multipath we use a channel impulse response$nction based on a tapped-delay line model. We solve the combined model numerically using the Naval Research Laborato y Impulse Response Function Simulator code (NCIRFS) for several modulation waveforms for bothfiequencyselective andfiequency 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.

Preliminary Composite Channel Model for the Mobile User Objective System Including Ionospheric Scintillation and Terrestrial Multipath Effects

“…The general expression for the signal auto-correlation function [1,3] R(T,Af) = <E(t+T,f+Af)E*(t,f)> (2) where E is the complex envelope representation of the signal with * denoting complex conjugate and <.> the expectation operator. For the Rayleigh scintillation channel without terminal Doppler we have the normahzed auto-correlation function [1,2] p(…”

“…In the past ionospheric scintillation and terrestrial multipath fading have been studied separately. Some initial efforts have been made to develop a composite model [1][2][3][4][5]. A composite model is important for waveform design, signal demodulation, and fading mitigation.…”