path correlation
TRANSCRIPT
Path Correlationthrough Penetration to Buildings
•Dr. Joseph Shapira
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Contents
• Propagation modes1. Sources of waves impinging on the outer wall2. Reflection and transmission through walls3. Transmission through apertures4. Propagation within a room5. Coupling into inner rooms 6. Indoors-generated transmission • Paths’ correlation1. Correlation between impinging sources2. Correlation between offspring branches (reflections and
diffractions of each penetration mode)
•
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Propagation modes
1. Impinging waves
2. Wall penetration
3. Aperture penetration
4. Transmission through• multiple walls
5. Propagation within the room
6. Coupling to inner rooms
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1
2
3
4
5
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Sources of waves impinging on the outer wall
1. Direct (LOS)1. Remote source – plane wave. Full correlation between source
antennas.2. Near source (across the street). Full de-correlation at edges of the
aperture d – source antennas spacing; D – aperture; R- distance
2. Remote reflector – each reflector is a remote source. The distance between the reflectors – d, determines the correlation between them.
3. Over the roof, and around-the-wall diffraction – these are line sources. Create a single ray in the plane of the line.
4. Propagation along the street (waveguide propagation). Impinges on the wall at low grazing angle, high attenuation. Reflectors or line diffractors across the street, generate wave impinging near normal incidence and may be stronger.
RdD λ≥
4
Transmission through the wall – the angular filter
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Γ T Γ T
H polarization
V polarization
(incidence in horizonthal plane)
Window penetration
•First Fresnel zone
•Diffraction zone – attenuated by•ceiling and furniture clutter
•Transition zone holds for
•W,Wi flux density, i incident
{ }dWW i α−= exp
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λ4
2sd =
22
2
=
hd
A
W
W
i πλ
λ s
dh
4
λ>
h
1st Fresnel zone
Edge diffraction
The window penetration depth
ϑ2cos
( ) ϑλ 22 cos4' sd =
7
d
d'
Free space penetration depth filter
Wall reflection loss
Reflection loss [dB]
-15.00
-13.00
-11.00
-9.00
-7.00
-5.00
-3.00
-1.000 8 16 24 32 40 48 56 64 72 80 88
Angle from zenit, degrees
Re
fle
cti
on
los
s [
dB
]
TM, Eps=3
TE, eps=3
TM, eps=6
TE, eps=6
TM, eps=10
TE, eps=10
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V polarization
H polarization
Room reflections
• The reflection loss is not trivial• Up to 10 dB per reflection.
• The direct ray is dominant
• Scattering from objects near the• UE (e.g person) competes with• high order reflection
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θ
−θ180+θ
180−θ
Γ2Γ4
Γ6
Reference to reported observations
• Mischa Dohler et. Al. :MiMO channel measurements, IEEE Communications Magazine • March 2007
• Most contributions are LOS. Then only single bounce counts. Others, and diffractions, are too small
• Propagation along corridor – key-hole effect. DOA is only along the corridor axis.
• Clustered multipath are correlated
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Direction-of-arrival measurements
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A. Molisch. The BS was placed across the street against the building
Indoor-generated transmission
• Reciprocity imples dominance of direct + 1st reflection
• Within the same room– scattering rich.
• Through walls to other rooms – angular filter through each wall. However, multiple rays may have equal strength (due to complexity of environment, e.g. corridor propagation etc.). A range of richness dimensions.
• Indoors to outdoors – by reciprocity,
• same as out-indoors.
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Correlation analysis
•LOS remote source penetrates the wall/ window as a plane wave. Full correlation.•Edge diffraction of the window is directive. The diffraction of both edges overlap too far to meet the de-correlation condition•Over-the-roof diffraction is coherent in the horizontal plane.•Around-the-corner diffraction is coherent in the vertical plane.•The outer wall/ window does not change the correlation of the penetrating waves. However, it acts as an angular filter, limiting the range of incidence.•Indoor reflections are attenuated. Only direct and 1st bounce count. The correlation of the incoming waves does not change.
RdD λ≥
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Correlation analysis - 2
• The indoor multipath is mainly of order 1 – 2 (diffraction by a close-by object may add).
• The degree of source depends on the number of angularly separated reflection/ scattering that hit the wall with similar strength through the wall angular filter. This may typically be 1 – 2.
• The MIMO degree is thenMost 1 – 1then 1 – 2then 2 – 2rarely higher
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