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

Summary of Recommendations 12-5
that of the static run except that the range of validity is different in percentage and
attenuation ranges.
12.3.3 Suggestions for Future Efforts
The EERS formulation has been validated at 870 MHz, 1.5 GHz, 3 GHz and 20 GHz. It
is recommended that further validation be applied at 5, 10, and 15 GHz. This formulation
should be further extended to frequencies in excess of 20 GHz for systems where
appropriate fade margins are available.
12.4 Signal Degradation for Line-of-Sight Communications (Chapter 4)
Cumulative fade distributions are presented for land-mobile satellite scenarios where
multipath is the dominant cause of signal degradation. The multipath environment may
be due to roadside trees, utility poles, terrain, or a nearby body of water and is generally
dependent on the antenna beamwidth characteristics.
12.4.1 Empirical Multipath Model
The following empirical multipath model is valid at frequencies between 870 MHz and
20 GHz and elevation angles between 8° and 60°.
For 1% ≤ P ≤ 50% or 0. 6 ≤ A ≤ 4. 6 dB
P = 9437 . ⋅ exp( −9863 . ⋅ A)
, (12-12)
where P is the percentage of the distance driven over which the attenuation A (dB) is
exceeded, assuming only multipath conditions. The model distribution uncertainty is
approximately within ± 1.5 dB of 12 measured distributions at equal percentages greater
than 2%. Between 1% and 2%, it is within ± 3 dB.
The model (12-12) includes scenarios that correspond to: (1) canyons at 870 MHz and
1.5 GHz for 30° and 45° elevations, (2) rolling hills and mountains at 1.5 GHz for
elevation angles of 10° to 14°, (3) roadside tree measurements at 870 MHz and 1.5 GHz
for elevation angles from 10° to 60°, (4) roadside tree measurements at 20 GHz for an
elevation angle of 38°, (5) open fields and near-water at 20 GHz for elevation of 8° for
which the vehicle shielded reflections from the water. The formulation (12-12) does not
apply to scenarios where multipath reflections from nearby bodies of water may exist and
are not filtered out by the antenna gain characteristics. Such measurements gave fades as
high as 14 dB at the 1% level. Maritime multipath models described in Section 12.9 (and
Chapter 9) should be used when receiving multipath reflections from a nearby body of
water.
Multiple type antennas were used for the above-described measurements. These included
the following: (1) UHF and L-Band measurements at elevations between 30° and 60° for
canyons and tree-lined road scenarios were executed using an antenna beamwidth of 60°
(15° to 75° in elevation and azimuthally omni-directional). (2) Low elevation L-Band