Definition and Analysis of Quasi-Stationary Intervals of Mobile Radio Channels - Invited Paper

Abstract

This paper presents a non-wide-sense stationary uncorrelated scattering (non-WSSUS) model which takes accurately into account that the Doppler frequencies and propagation delays vary with time if the mobile station (MS) moves. Another feature of the proposed channel model is that the MS can change its velocity along the route. The result is that the Doppler spread and the delay spread deviate from their initial values with increasing time. This effect motivates the definition of quasi-stationary intervals. The lengths of these intervals will be analysed in terms of the velocity parameters. Our analysis shows that real- world channels can be quasi-stationary but not wide-sense stationary (WSS), neither in the time domain nor in the frequency domain. This implies that the generally accepted WSS and WSSUS assumptions are not fulfilled in practice, even not if the travelling distance is short.