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

Fade and Non-Fade Durations and Phase Spreads 5-11
5.8 Cumulative Distributions of Non-Fade Duration: Central Maryland
Also shown plotted in Figure 5-7 are 1.5 GHz non-fade duration distributions derived
from helicopter measurements in central Maryland for elevation angles of 30°, 45° and
60° [Goldhirsh and Vogel, 1989]. It is noted that these distributions generally flank the
interval of durations derived employing the Australian measurements (51° elevation)
between the “extreme” and “moderate” cases. At the 10% probability, the 60° central
Maryland distribution coincides with the “moderate” case and the 30° distribution is
close to the “extreme” distribution. Close agreement between the above curves also
exists at the median level.
Percentage of Non-Fade Durations > Abscissa
100
9
8
7
6
5
4
3
2
10
9
8
7
6
5
1
4
3
2
Extreme
Central MD
Distribution
Moderate
30°
45°
60°
2 3 5 2 3 5 2 3 5 2 3 5
0.1 1.0 10.0 100.0 1000.0
Non-Fade Duration Distance (m)
Figure 5-7: Best fit power curves (5-6) showing non-fade duration distributions for a
5 dB threshold for road types which exhibit “moderate” and “extreme” shadowing.
5.9 Cumulative Distributions of Phase Fluctuations: Australian
Measurements
Through further analysis of the Australian data base, phase time-series were obtained
from measured I and Q components after variations due to Doppler and oscillator drifts
were eliminated using a high pass filter [Hase et al., 1991]. Conditional cumulative