Kein Folientitel

1
Propagation Channel Characterization and Modeling
Outdoor Power Supply Gridsas Communication
Channels Prof. Dr.-Ing. habil. Klaus Dostert
Institute of Industrial Information
Systems UNIVERSITY OF KARLSRUHE (TH)
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Overview
Communication over outdoor electrical power
supply lines

• Network structures and their basic properties
• Access domain in Europe, ASIA, America

• Analysis of line and cable properties
• characteristic impedance
• branching matching

• General aspects of channel modeling
• transfer function, impulse response, channel
  parameterization
• interference scenario

• PLC channel simulation and emulation
• channel adapted system development

Conclusions and further work
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History Carrier Frequency Transmission since
1920 (on the high voltage level only)

• no branching
• optimal wave guiding by network
  conditioning

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Current and Upcoming PLC Applications
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The European Power Supply Network Structure
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Typical Topology of European Power
DistributionNetworks in Residential Areas
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Some Details of Last Mile and Last Meter
Environments
ZL2
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Power Supply Structures in Asia and America

• small supply cells
• few households per transformer
• cable length ?? 100m
• grounding of 3rd wire
• highly unsymmetrical

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The Ideal Two-Wire System
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Symmetry in Multi-Wire Structures
open wires
X

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Simplified Analysis of a Two-Wire System
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RF Properties of Typical Supply Cables
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The problem of Branching and Possible Solutions
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Some Ideas for Signal Coupling with Enhanced
SymmetryImproving EMC
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Reflections Causing Echoes and Inter-Symbol
Interference
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Approaches Toward Deterministic Network Modeling
source
sink
line element
bq ri

• high computational effort
• requires detailed knowledge of
• network topology and device parameters
• not applicable in practice

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The Echo-based Channel Model
considering only echoes kiconst
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H(f) single reflection, no losses
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Two-Path Channel without Losses but Varying Path
Weights
Path 1
0.52
0.26
0.173
0.46
0.71
0.793
0.627
Path 2
0.347
0.208
0.149
0.76
0.817
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A First Realistic Example
path di/m gi
1 200 0.64
2 222.4 0.38
3 244.8 -0.15
4 267.5 0.05
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A Second Example (more complex)
path di/m gi
1 90 0.029
2 102 0.043
3 113 0.103
4 143 -0.058
5 148 -0.045
6 200 -0.040
7 260 0.038
8 322 -0.038
9 411 0.071
10 490 -0.035
11 567 0.065
12 740 -0.055
13 960 0.042
14 1130 -0.059
15 1250 0.049
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Transmission Characteristics According to Length
Classes
0
10
Attenuation in dB
20
30
150 m
40
200 m
50
60
300 m
70
380 m
80
2
4
6
8
10
12
14
16
18
Frequency in MHz
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A General Powerline Interference Model
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Idea of a Universal PLC-Channel Emulator
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Some Details Toward Emulator Realization
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A First Powerline Channel Emulator Prototype
modified filter structure
reference channel
coeff. filter 1 coeff. filter 2
H in dB
simulations, implementation
H in dB
hardware
f in MHz
verification measurements
f in MHz
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Why OFDM for PLC?
Channel Transfer Function
restricted e.g. for protection of broadcast
services
f
fN
f1
f2
f3
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Conclusions and Further Work