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

Maritime-Mobile Satellite Propagation Effects 9-17
Step 5: Evaluate T ( 95%)
at the upper and lower bounds of f-10.
D
Substituting (9-33) and (9-38) into (9-29),
TD U
D
L
( 95%)
= 0.
14s,
T ( 95%)
= 1.
05s
(9-39)
In Figure 9-12 through Figure 9-14 are given pairs of curves showing the spread of the
mean fade occurrence interval TI (P)
versus elevation angle at the aforementioned
maritime bounds for exceedance probabilities of multipath fading P of 99%, 95%, and
90%, respectively. In Figure 9-15 through Figure 9-17 are given analogous sets of curves
for the mean fade durations (P)
. Consistent with the fact that higher exceedance
T D
percentages imply greater multipath fading, the spread (difference between upper and
lower bound values for a fixed elevation angle) of the mean fade occurrence interval is
greater at the higher percentages (larger fades) and smaller at the lower percentages
(smaller fades). Analogously, the mean fade duration spread is smaller at the higher
percentages (greater fading) and larger at the smaller percentages (smaller fading).
Mean Fade Occurrence Interval, T I (sec)
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
Lower Bound f -10
Upper Bound f -10
P = 99%
5 6 7 8 9 10 11 12 13 14 15
Elevation Angle (deg)
Figure 9-12: Bounds of mean fade occurrence interval TI (P)
for multipath fade
exceedance percentage P = 99% at L-Band.