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

Table of Contents
6 Polarization, Antenna Gain and Diversity Considerations ___________________ 6-1
6.1 Background _________________________________________________________ 6-1
6.2 Depolarization Effects_________________________________________________ 6-1
6.3 Distributions from Low- and High-Gain Receiving Antennas ________________ 6-2
6.4 Fade Reduction Due to Lane Diversity ___________________________________ 6-4
6.5 Antenna Separation Diversity Gain______________________________________ 6-7
6.5.1 Joint Probabilities _______________________________________________________ 6-8
6.5.2 Diversity Improvement Factor, DIF _________________________________________ 6-8
6.5.3 Diversity Gain _________________________________________________________ 6-10
6.5.4 Space Diversity for Expressway and Trunk Road Driving in Japan ________________ 6-11
6.6 Satellite Diversity____________________________________________________ 6-12
6.6.1 Background ___________________________________________________________ 6-12
6.6.2 Cumulative Distributions_________________________________________________ 6-12
6.6.3 Satellite Diversity Gain __________________________________________________ 6-13
6.6.4 Satellite Diversity Measurements at S-Band Employing TDRSS __________________ 6-14
6.7 Conclusions and Recommendations_____________________________________ 6-16
6.8 References _________________________________________________________ 6-16
Table of Figures
Figure 6-1: Cross polarization isolation (CPI) as a function of co-polarization fade at equiprobability
levels.......................................................................................................................... 6-2
Figure 6-2: Fades measured by high- and low-gain systems at equi-probability levels............................ 6-4
Figure 6-3: Mobile satellite scenario showing larger intersecting path length through tree canopy for
inner lane driving relative to the outer lane case. ........................................................................... 6-5
Figure 6-4: Fade reduction due to switching lanes at 870 MHz versus equi-probability attenuation at
the indicated path elevation angles................................................................................................ 6-6
Figure 6-5: Fade reduction due to switching lanes at 1.5 GHz versus equi-probability attenuation
(inner lane) at the indicated path elevation angles.......................................................................... 6-6
Figure 6-6: Single and joint probability fade distributions for mobile communications operating in a
space diversity mode with antennas separated by the distance, d.................................................... 6-9
Figure 6-7: Diversity Improvement Factor (DIF) as a function of fade depth for a family of antenna
separation distances...................................................................................................................... 6-9
Figure 6-8: Diversity gain versus antenna separation distance for a family of single terminal fade
levels.......................................................................................................................................... 6-10
Figure 6-9: Cumulative fade distributions at L Band (f ≈ 1.6 GHz) for the simulated Globalstar
constellation with combining diversity for Tokyo, Japan [Vogel, 1997, Akturan and Vogel,
1997]. ........................................................................................................................................ 6-13
6-i