Transcript Prezentacja programu PowerPoint
COST 286 Electromagnetic Compatibility (EMC) in Diffused Communication Systems Hamburg, 25th-26th November, 2004
Research on simulating radiowave propagation in closed environments
Kamil Staniec Wroclaw University of Technology Institute of Telecommunications and Acoustics
Wybrzeże Wyspiańskiego 27, 50-370 Wrocław Poland e-mail: [email protected]
2.4
Technological congestion IEEE 802.11b
IEEE 802.11g
HomeRF Bluetooth SRD’s ZigBee ENG/OB
ISM 2.4835
HyperLAN 1/2 IEEE 802.11a
Low Middle
U-NII 5.15 - 5.25
5.25 - 5.35
High
5.725-5.725
[GHz]
RFID Military Domestic Sulphur plasma lighting
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AP1
Current measurements – mixed configurations
distance_1
1. 802.11b - 802.11g (interference) 2. 802.11a - 802.11b/g (no interference) 3. Bluetooth - 802.11b/g (interference)
Test session Monitor U2 U1 Interfering session dis ta nc In te rfe re nc e e_ 2
(> d ist an ce _1 )
AP2 2 /21
Existing indoor propagation models
1. Statistical models:
1.1 Amplitude distribution 1.2 Phase distribution 1.3 Angle-of-arrival distribution
2. Empirical models
2.1 ITU-R P.1238:
L
20 log
f
N
log
d
L f
(
n
) 28 2.2 Multilayer model:
L
PL
(
D
0 ) 10
n
log(
D
/
D
0 )
k
AF k FAF = 15+(5
10)*k [dB]
FAF
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OUTER WALL
Indoor propagation effects
TX PARTITION WALL BUILDING INTERIOR
Reflection Transmission Diffraction Scattering
FURNITURE FLOOR
[modified 3]
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Multipath propagation {a k1 , k1 } {a k2 , k2 } t k1 t k2 {a kn , kn } t kn
h
(
t
, )
N k
( ) 0 1
a k
(
t
) [
k
(
t
)]
e j
k
(
t
) k-th path {a k , t k , k } t
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Tx
Advantages of using ray tracing method: imitates radiowave propagation
R x1 R x2
E i
Z
0 4
dL Di P
0 (
d
)
G ti G ri
m D
(
mi
)
j
(
ji
)
k T
(
ki
)
e
j
2
d
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Advantages of using ray tracing method: easy generation of any antenna patterns
patterns drawn with 642 rays
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P Advantages of using ray tracing method: radio channel power delay time profile
rms
P i 0.1
0.2
0.3
m
0.4
0.5
0.6
0.7
s
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Indoor propagation – challenges to be solved
Common assumptions in existing RT model:
•
constant wall attentuation (irrespective of material electric parameters)
•
walls/partitions perfectly thin
•
presence of objects/persons not considered
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Research – our objectives Create
exact
analytical model that includes: • persons/objects • „thick” walls • variable attenuation of partitions • radio channel time-dispersion characteristics
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15 mm 120 mm 100 mm 120 mm 15 mm X-section of a partition wall
CONCRETE BRICK MINERAL WOOL BRICK CONCRETE 11 /21
Multilayer structure – influence of innacurate electric parameters
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Multilayer structure – wall attenuation vs. incidence angle Pol H Pol V
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Multilayer structure – EM wave attenuation vs. frequency Pol H Pol V Light concrete 15 mm Brick 120 mm Mineral wool 100 mm Brick 120 mm Light concrete 15 mm
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Infinite thinness Thick / thin walls modeling Actual thickness
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Analytical calculation of multilayer wall attenuation
0 0 d 1
1 1 d 2
2 2
0 0
1 2 1 2 1
r
i
1
2
t 16 /21
Simulated environment (example)
Thick walls with persons (yellow) and objects (green)
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Tx
Optimisation 1: Environment prescanning
VISIBLE ITEMS INVISIBLE ITEMS 18 /21
Optimisation 2: look-up table in variable attenuation calculations Look-up table Av=34,581 dB Rv=0,425 P0 Inc. angle=10 o Pr = P0 * R v Pt = P 0 A v
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State of research: • Environment database preprocessing accomplished: • available modes: • perfectly thin walls • actually thick walls • inclusion of persons • inclusion of furniture • variable walls attenuation w/r to frequency, incidence angle, polarization (database storage) • Preliminary ray tracing for „full” ray tracing optimisation purposes (av. 95% time saving)
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Possible applications: • e-field distribution maps in a closed environment (SOHO, vehicles, railway tunnels) • information on radio channel dispersiveness - Power Delay Profile /available for each pixel/ • modeling mutual AP’s interference
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