# Table 2 Ground-reflected ray parameters

Parameter Value
Delay Ground-reflected ray delay is calculated from the model geometry:
τ G  = d G /c
$${d}_G=\sqrt{L^2+{\left({H}_{tx}+{H}_{rx}\right)}^2}$$
Power Ground-reflected power calculated as free-space path loss with oxygen absorption, with additional reflection loss calculated on the base of the Fresnel equations. Reflection loss R is different for vertical and horizontal polarizations
$${P}_{\perp }=20{ \log}_{10}\left(\frac{\lambda }{4\pi {d}_G}\right)-{A}_0{d}_G+{R}_{\perp }+F;$$
$${P}_{\parallel }=20{ \log}_{10}\left(\frac{\lambda }{4\pi {d}_G}\right)-{A}_0{d}_G+{R}_{\parallel }+F$$
$$F=\raisebox{1ex}{80}\!\left/ \!\raisebox{-1ex}{ \ln 10}\right.{\left(\pi {\sigma}_h \sin \phi /\lambda \right)}^2$$
$${R}_{\perp }=20{ \log}_{10}\left(\frac{ \sin \phi -\sqrt{B_{\perp }}}{ \sin \phi +\sqrt{B_{\perp }}}\right);\ {R}_{\parallel }=20{ \log}_{10}\left(\frac{ \sin \phi -\sqrt{B_{\parallel }}}{ \sin \phi +\sqrt{B_{\parallel }}}\right)$$
B  = ε r  − cos2 ϕ for horizontal polarization.
$${B}_{\perp }=\left({\varepsilon}_r-{ \cos}^2\phi \right)/{\varepsilon}_r^2$$ for vertical polarization,
where $$\tan \phi =\frac{H_{tx}+{H}_{rx}}{L}$$ and σ h is a surface roughness.
Channel matrix $$\mathbf{H}=\left[\begin{array}{cc}\hfill {10}^{P_{\perp }/20}\hfill & \hfill \xi \hfill \\ {}\hfill \xi \hfill & \hfill {10}^{P_{\parallel }/20}\hfill \end{array}\right]{e}^{\frac{j2\pi {d}_G}{\lambda }}$$
AoD Azimuth: 0°, elevation: $${\theta}_{AoD}={ \tan}^{-1}\left(\frac{L}{H_{tx}-{H}_{rx}}\right)-{ \tan}^{-1}\left(\frac{L}{H_{tx}+{H}_{rx}}\right)$$
AoA Azimuth: 0°, elevation: $${\theta}_{AoA}={ \tan}^{-1}\left(\frac{H_{tx}+{H}_{rx}}{L}\right)-{ \tan}^{-1}\left(\frac{H_{tx}-{H}_{rx}}{L}\right)$$
1. AoD angle of departure, AoA angle of arrival