Log-Normal Fade Margins
The Log-normal fade margin is
incorporated in to the link budget calculation to ensure coverage reliability,
and there are three environmental cases to consider:
· Outdoor fade
margin
· Indoor fade
margin
· In-vehicle
fade margin
Outdoor Fade Margin
The outdoor standard deviation α0, depends on the terrain: dense urban, urban, or
suburban and may change very slightly with frequency. The outdoor standard
deviation, α0, ranges from
5 dB (rural) to 12 dB (dense urban) with a typical value of 8 dB (suburban) Radio
Wave Propagation A
Indoor Fade Margin
If an MS is inside a building,
the received signal is attenuated as it passes through the exterior of the
building. Building penetration loss, Lbp is
subject to random variation. We denote the standard deviation of the building
penetration loss as αbp. The standard
deviation, α, used to compute the indoor fade margin accounts
for the outdoor environment, as well as the random variation of the building
penetration loss. The standard deviation, α 0, is pooled with α bp.
Thus the pooled deviation,
In-vehicle Fade Margin
The in-vehicle loss is also
variable; therefore, the standard deviation, α ,
should account the outdoor environment, as well as the random variation of the
in-vehicle penetration loss. We denote the standard deviation of the in-vehicle
penetration loss as αiv. The standard
deviation, _iv, must be pooled with the outdoor standard deviation αiv. The pooled standard
Comments