Calculation of the Overall Path Loss The overall path loss at a distance d and a carrier frequency f can be modelled as: (1) where Specific Attenuation by Atmospheric Gases according to ITU-R P.676-10 Two methods are described in ITU-R P.676-10 [6.2]: A more detailed line calculation of gaseous attenuation –by-line A simplified method, based on curve-fitting of the line-by-line calculation agrees with the more accurate calculations to within an average of about 10% at frequencies removed from the centres of major absorption lines. The absolute difference between the results from these algorithms and the line-by-line calculation is generally less than 0.1 dB/km and reaches a maximum of 0.7 dB/km near 60 GHz. In the following the specific attenuation due to dry air and vapour, is estimated using the simplified algorithms, valid for the frequency range 120 to 350 GHz: The specific attenuation due to dry air is calculated using the following equations: o (2) (3) (4) frequency (GHz) f = where represents total air pressure rp ptot/1013, ptot 288/(273 rt t) pressure (hPa) p t temperature (C)
Calculation of the Overall Path Loss The overall path loss at a distance d and a carrier frequency f can be modelled as: (1) where Specific Attenuation by Atmospheric Gases according to ITU-R P.676-10 Two methods are described in ITU-R P.676-10 [6.2]: A more detailed line –by-line calculation of gaseous attenuation A simplified method, based on curve-fitting of the line-by-line calculation agrees with the more accurate calculations to within an average of about 10% at frequencies removed from the centres of major absorption lines. The absolute difference between the results from these algorithms and the line-by-line calculation is generally less than 0.1 dB/km and reaches a maximum of 0.7 dB/km near 60 GHz. In the following the specific attenuation due to dry air and vapour, is estimated using the simplified algorithms, valid for the frequency range 120 to 350 GHz: The specific attenuation o due to dry air is calculated using the following equations: (2) (3) (4) f frequency (GHz) rp = ptot/1013, where ptot represents total air pressure rt 288/(273 t) p pressure (hPa) t temperature (C)
15-14-0310-14-003d-channel-modeling-document.docx