Handbook of Propagation Effects for Vehicular and ... - Courses

Theoretical Modeling Considerations 11-7
Urban and Commercial
( PS
− 90)
⋅ 0.
6 + A(
PL
)
A(
PL
, PS
) =
( P − 90)
⋅ 0.
2 + A(
P )
Suburban-Rural
S
L
95%
95%
≥ P
S
≤ P
S
≥
<
90%
90%
(11-15)
A ( PL
, PS
) = ( PS
− 90)
⋅ 0.
1 + A(
PL
) 95% ≤ P S ≤ 90%
(11-16)
Table 11-1: Parameter Definition and Values for Hess Model.
Parameter Range of Values
ENVironment 1 = Urban, 0 = Commercial, -1 = Suburban/Rural
HEADing cos( 2(
Vehicle Satellite )) Az Az −
−
FREQuency 1 = UHF, 1.8 = L-Band
SIDE of road +1 = Satellite across road, -1 = On same side
ELEVation 15° to 50°
Table 11-2: Coefficients in LS-SS Fade Model.
Mean Fade, μ Standard Deviation, σ
Coefficient Value (dB) Std. Error (dB) Coefficient Value (dB) Std. Error (dB)
a0 9.55 b0 3.75
a1 4.46 0.42 b1 2.62 0.29
a2 3.41 0.61 b2 0.98 0.42
a3 1.66 0.91 b3 0.046 0.62
a4 -0.35 0.36 b4 -0.24 0.25
a5 -0.052 0.045 b5 0.04 0.031
11.3.1.1 Example: LS-SS Model
To illustrate the procedures by which we execute the LS-SS model, consider the
following example. Assume that a receiver can recover the LMSS coded errors as long
as the small-scale coverage is at least PS = 70%. The system operates at L-Band in a
suburban area with an elevation angle to the satellite of 45°. It is desired to determine the
required fade margin to achieve a large-scale probability of PL = 95%.
We assume a worst case heading and condition of roadside, with the satellite at a
right angle to and right of the vehicle. Hence, we employ the following parameter values
from Table 11-1: