Modeling of First-Order Statistics of the MIMO Dual Polarized Channel at 2 GHz for Land Mobile Satellite Systems Under Tree Shadowing

The Land Mobile Satellite (LMS) channel at 2 GHz is examined and the first order statistics are modeled using experimental data for two tree shadowing scenarios. Considering that the first order statistics of the channel are used as input to channel models as well as for the calculation of the system margins, the modeling of the probability density function (PDF) and the cumulative distribution function (CDF) of the received signal envelope is of great importance for the design of LMS systems. Experimental data from measurements performed in Prague, the Czech Republic, are presented for two scenarios, a Heavy Tree Shadowing one and an Intermediate Tree Shadowing one. Four of the most widely used distributions, Rayleigh, Rice, Loo and lognormal, are considered for the modeling of the CDF of the signal envelope. Loo and Rice distributions out of the four considered distributions provide the best fit with reference to the measured data. Moreover, analytical empirical expressions are given for the parameters of the Loo distributions as a function of the elevation angle, to be used for the modeling of the LMS channel under tree shadowing. It is found that the expressions for the estimation of the distributions´ parameters provide a good fit to the experimental data.