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

8-16
Signal Level Relative to
Copolarized Clear Path (dB)
20
10
0
-10
-20
-30
-40
-50
-60
Co-Polarized Reception
L
S
L
Propagation Effects for Vehicular and Personal Mobile Satellite Systems
S L
S
L S
Frequency Band and Location
L
Non-Outlier Max...Min
95%...5%
Median
S L
Commons EERL Farmhouse House Motel Store
Figure 8-9: Summary of statistics at L- and S-Band giving median, 95%, and 5% levels
of the relative power losses inside the six buildings for the case in which the antennas
were moved horizontally over multiple 80 cm intervals.
Table 8-8: Summary of medians of the relative signal loss inside the six buildings at L-
(1618 MHz) and S-Band (2492 MHz).
Site
Median Fade (dB)
L-Band S-Band
Commons -18.6 -17.1
EERL -14.7 -15.1
Farmhouse -6.5 -7.5
House -9.1 -8.4
Motel -18.5 -19.7
Store -13.7 -19.2
Average -13.5 -14.5
The overall averaged cross-polarized relative power levels are only 2.3 and 1.6 dB
smaller than the corresponding co-polarized power levels at L- and S-Band, respectively
(Table 8-9 and Table 8-10). For example, the average relative cross-polarized power
levels at L- and S-Bands are -16.9 dB and -16.7 dB, whereas the average relative copolarized
levels are -14.6 dB and -15.1 dB. These results suggest that the isolation
between polarizations inside buildings is small, obviating the possibility of employing
intra-system frequency re-use for gaining additional spectral capacity, although not the
possibility of inter-system frequency re-use for achieving higher isolation between
different satellite communications systems.
S