1.1.3 Statistical Characterization of Fading Channel 2.LOS propagation environments In the LOS environment where exists a strong path which is not subject to any loss due to reflection,diffraction,and scattering,the amplitude of the received signal can be expressed as X-C+W+jW, where C represents the LOS component while W and W,are the i.i.d.Gaussian random variables.It has been known that X is the Rician random variable with the PDF: where 1 is the modified zeroth-order Bessel function. 1313 1.1.3 Statistical Characterization of Fading Channel 2. LOS propagation environments In the LOS environment where exists a strong path which is not subject to any loss due to reflection, diffraction, and scattering, the amplitude of the received signal can be expressed as 2 2 2 2 2 2 0 ( ) x c X x xc f x e I                   X=C+W +jW 1 2 where represents the LOS component while and are the i.i.d. Gaussian random variables. It has been known that X is the Rician random variable with the PDF: C W1 W2 where is the modified zeroth -order Bessel function. 0 I