submission doc.: ieee 11-14/0088r0 jan 2014 igal kotzer, general motorsslide 1 intra-vehicle channel...
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Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 1
Intra-Vehicle Channel ModelDate: 20-Jan-2014
Name Affiliations Address Phone email Igal Kotzer General Motors
Authors:
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 2
Abstract
• In this submission the wireless channel inside a vehicle is discussed.
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 3
Introduction
• Wireless LAN is becoming a leading standard in vehicular communications• Many vehicle models today have a built in WLAN communication
• WLAN is present in virtually every consumer electronic device
• Vehicle manufacturers adapt the vehicles to the changes in consumer electronics
• WLAN is used in intra-vehicle infotainment systems
• WLAN can also be used for vehicular sensor linking
• The number of vehicle models equipped with WLAN is constantly increasing
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 4
WLAN in the Vehicle – Channel Perspective
• The vehicular environment posts some unique challenges for WLAN systems aiming at providing top performance
• WLAN can be used in three vehicular scenarios:• Intra-vehicle communication – mainly for infotainment
• Inter-vehicle communication such as multimedia, mesh networking
• Vehicle to infrastructure
• In this submission the intra-vehicle 2.4GHz wireless channel will be discussed
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 5
Intra-Vehicle Wireless Channel Measurements Setup
• The wireless channel measurements were performed using the following equipment:• GM SUV vehicle
• Agilent PNA N5242A network analyser
• 4 omni-directional WiFi antennas in a 2x2 configuration
• In this setup there was no driver / passengers in the vehicle
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 6
Intra-Vehicle Wireless Channel Measurements Setup
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 7
Intra-Vehicle Wireless Channel Measurements Locations
Front of the vehicle Rear of the vehicle
1, 2, 3 Dashboard height A, B, C, D Rear passenger head height
4, 5, 6, 7 Kick Panels (Low behind dashboard)
E, F, G, H Rear passenger seat height
I, J, K, L Rear passenger foot height
M, N, O, P Trunk floor height
• All possible rear-front combinations were measured (112 measurements)
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 8
Intra-Vehicle Wireless Channel Measurements Locations
1
2
3
A
B
C
D
E
F
G
H
4
5
6
7
Trunk
I
J
K
L
M
N
O
P
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 9
Intra-Vehicle Wireless Channel Path Loss
10 15 20 25 30 350
0.02
0.04
0.06
0.08
0.1
0.12
0.14
Path Loss [dB]
Pro
b.
De
nsi
ty F
un
ctio
nIntra-Vehicle Path Loss PDF
MeasurementsModel fit
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 10
Intra-Vehicle Wireless Channel Path Loss
• Measurement results fit the model: • - total path loss
• - mean path loss
• – shadowing, log normal zero mean r.v.
• Comparison between model parameters and wireless indoor model:
Wireless indoor model
Intra-vehicle based model
Mean path loss Free space path loss43dB @ 1.5m
19dB
Shadowing variance
3dB for 10dB
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 11
Intra-Vehicle Wireless Channel Delay Spread
10 15 20 25 30 35 400
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Channel Delay Spread [ns]
Pro
b.
De
nsi
ty F
un
ctio
nIntra-Vehicle Channel Delay PDF
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 12
Intra-Vehicle Wireless Channel Path Loss
• RMS channel delay spread: 22ns
• No clustering effect was seen
Wireless indoor model Intra-vehicle based model
RMS channel delay spread 40ns – 600ns for one cluster 22ns
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 13
Intra-Vehicle MIMO Channel Matrix Condition Number and Rank
• All of the measured 2x2 MIMO channel matrices have a rank of 2
• The channel matrix’s condition number varies significantly between bands and within bands.• Based on the measurements the condition number varies between
0dB to 30dB
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 14
Intra-Vehicle Wireless Channel Matrix Condition Number and Rank
2.4 2.42 2.44 2.46 2.48 2.505
101520
3A
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
11.5
2
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3B
Con
diti
on
Nu
mb
er
[dB
]Freq. [GHz]
2.4 2.42 2.44 2.46 2.48 2.5
11.5
2
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
10
3C
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
2
3
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3D
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
11.5
2
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
101520
3E
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3FC
ond
itio
n N
um
be
r [d
B]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
101520
3G
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
10
3H
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
2
3
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
10
3I
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
2
3
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3J
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
11.5
2
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
101520
3K
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
11.5
2
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
101520
3L
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
11.5
2
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3M
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3N
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.505
101520
3O
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
2.4 2.42 2.44 2.46 2.48 2.50
10
20
30
3P
Con
diti
on
Nu
mb
er
[dB
]
Freq. [GHz]2.4 2.42 2.44 2.46 2.48 2.5
1
1.52
2.53
Cha
nne
l M
atr
ix R
ank
Submission
doc.: IEEE 11-14/0088r0Jan 2014
Igal Kotzer, General MotorsSlide 15
Intra-Vehicle Wireless Channel Discussion
• The RX power of an intra-vehicle WLAN system is strong relative to indoor scenarios• Initial measurements of inter-vehicle interference suggest RX SNR
of about 30dB
• The intra-vehicle channel delay spread is very short, thus it is possible to shorten the CP and gain efficiency
• It is theoretically possible to achieve full 2x2 MIMO, however due to large changes in the streams’ power it is hard to implement practically. Addressing this issue, especially in a non Rx power limited environment can increase performance.