Theoretical Background for Modeling on Non-Stationary Channels

摘要

Models of randomly time-variant, frequency-selective, communication channels commonly employ statistical representations of channel input-output system functions, such as the time-variant impulse response or the time-variant transfer function, with Gaussian first order statistics. The additional assumption that the channel is WSSUS, that is, the second order statistics of the channel system functions are wide-sense stationary in time (or equivalently uncorrelated in Doppler) and uncorrelated in delay (or equivalently wide-sense-stationary in carrier frequency), lead to simple and elegant doubly-stationary channel model formulations. The assumption of double-stationarity holds for a very diverse range of narrow-band channels, and the Gaussian-WSSUS model has received much attention and use. The applicability of such a mode to some advanced modem concepts of current interest, such as meteor burst links and wideband HF communication techniques, however, cannot always be justified. Keywords: Striations; Power Spectra.