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

Investigations from Different Countries 7-23
Percentage of Time Fade > Abscissa
100
9
8
7
6
5
4
3
2
10
9
8
7
6
5
1
4
3
2
Location
Slidell, LS (41°)
Sequoia N.P., CA (18°)
0 2 4 6 8 10 12 14 16
Fade Depth (dB)
Figure 7-27: Cumulative fade distributions at 2.09 GHz for tree-lined roads at two
locations in the United States derived from spread spectrum transmissions [Jenkins et al.,
1995].
In Figure 7-28 are shown cumulative distributions derived from measurements at 20 GHz
(elevation angle = 46°) employing the Jet Propulsion Laboratory’s ACTS Mobile
Terminal (AMT) [Rice et al., 1996; Gargione et al., 1995]. The AMT is a “proof of
concept breadboard terminal” comprised of a tracking antenna system atop a van and is
being used to establish the operational capabilities of 20 GHz and 30 GHz mobile
communication systems [Abbe et al., 1996]. Rice et al. defined the road types over
which propagation measurements were made in the following way:
• Category II: “A broad suburban thoroughfare lined with trees and buildings. The
tree canopies cause intermittent blockage and the buildings are either too far
removed from the roadside or not tall enough to cause significant blockage.”
• Category III: “A small, two-lane roadway lined with trees and buildings. The tree
canopies often cover the entire roadway and buildings are close enough to
contribute to the fading process.”
The curves labeled 1 and 3 in Figure 7-28 correspond to the Category II and the curves
labeled 4 and 5 represent Category III. Curve 2, given by Gargione et al. [1995], was
derived from measurements over a series of roads that encircle the Rose Bowl in
Pasadena, California. The road types were characterized as being “surrounded by rolling
hills with substantial amounts of foliage.”