A STUDY OF A LAND MOBILE SATELLITE CHANNEL MODEL WITH ASYMMETRICAL DOPPLER POWER SPECTRUM AND LOGNORMALLY DISTRIBUTED LINE-OF-SIGHT COMPONENT

In satellite to mobile communications, there is generally, in addition to the diffuse multipath component, a strong line-of-sight (LOS) comp onent present, The spectral and statistical properties of both compone nts are influenced by shadowing caused by obstacles such as trees, hou ses, or small buildings, In this paper, an analytical model for a land mobile satellite channel is analyzed that takes into consideration va rious kinds of shadowing situations, For the LOS component, it is assu med that, first, the received frequency shows a Doppler shift, Second, the amplitude variations coincide with a lognormal distribution, More over, it is also assumed that shadowing influences the diffuse scatter ed component, with the consequence that its Doppler power spectrum get s an asymmetrical shape, The resulting spectral and statistical proper ties of the analytical model are investigated, Exact solutions for, th e probability density function (pdf) of the amplitude and phase are gi ven, and approximative solutions for the level-crossing rate (LCR) and average duration of fades (ADF's) are derived, Finally, an efficient deterministic simulation model is presented that enables the implement ation of the proposed analytical model on a digital computer.