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

Summary of Recommendations 12-9
12.6.3 Effect of Switching Lanes
Where the satellite path is orthogonal to the driving direction, switching lanes is likely to
increase or reduce the fading depending on the elevation angle and the satellite location
relative to the vehicle direction (e.g., right or left of the vehicle). An equal probability
fade of 10 dB at UHF or L-Band, for example, was found to reduce to 5 dB at both
frequencies by switching lanes. The amount of fade reduction is elevation angle
dependent, i.e., the higher elevation angle scenarios (e.g., 60°) give greater fade reduction
than a smaller ones (e.g., 30°).
12.6.4 Diversity Gain by Spaced Antennas
Figure 12-2 depicts the diversity gain variation versus antenna separation distance for a
family of single terminal fade margins. These curves correspond to L-Band (1.5 GHz)
for tree-lined road scenarios. We note that two antennas pointing at the same satellite but
separated by 5 m will result in L-Band diversity gains of 3 dB and 5 dB at single terminal
fades of 5 dB and 10 dB, respectively. Increasing the separation to 10 m results in further
diversity gain improvements of only an additional 0.5 dB (at most) for these single
terminal fades.
Diversity Gain (dB)
8
7
6
5
4
3
2
1
0
14 dB
12 dB
10 dB
8 dB
6 dB
4 dB
3 dB
2 dB
1 dB
1 2 3 4 5 6 7 8 9 10
Antenna Separation, d (m)
Figure 12-2: Diversity gain versus antenna separation distance at 1.6 GHz for a family of
single terminal fade margins for tree-lined road scenarios.