Level-crossing rate and average duration of fades of non-stationary multipath fading channels

Abstract

The level-crossing rate (LCR) and average duration of fades (ADF) are important statistical quantities describing the fading behaviour of mobile radio channels. To date, these quantities have only been analysed under the assumption that the mobile radio channel is wide-sense stationary, which is generally not the case in practice. In this paper, we propose a concept for the analysis of the LCR and ADF of non-stationary channels. Rice's standard formula for the derivation of the LCR of wide-sense stationary processes is extended to a more general formula enabling the computation of the instantaneous LCR of non-stationary processes. The application of the new concept results in closed-form expressions for the instantaneous LCR and ADF of non-stationary multipath flat fading channels. The contribution of this paper is of central importance for the statistical characterization of non-stationary mobile radio channels.