Doubly Underspread Non-wssus Channels: Analysis and Estimation of Channel Statistics

The local scattering function (LSF) and the generalized channel correlation function have recently been introduced as intuitive and useful statistical characterization of fading channels that do not satisfy the usual WSSUS assumption [1]. In this paper, we present a generalized LSF and we demonstrate that for the subclass of practically relevant doubly underspread non-WSSUS channels, several useful approximations and interpretations for the LSF can be given. We further propose a computationally efficient, nonstationary multiwindow LSF estimator that yields reliable estimates in the case of doubly underspread channels even for a single channel realization.