Towards a European Solution for Networked Cars
-Integration of Car-to-Car Technology into Cellular Systems for Vehicular
Communication in Europe
Yunpeng Zang,
Bernhard Walke
Department of Communication Networks
RWTH Aachen University, Germany
Geneva, 4-5 March 2009
Sabine Sories,
Guido Gehlen
Ericsson Research,
Herzogenrath, Germany
Outline
o Introduction
o Car-to-Car Communication for Safety
o
o
o
o
Services
Vehicular Communication with Cellular
Systems
C2C vs. Cellular: Competing or
Complementary?
A Hybrid Solution
Conclusion
The Fully Networked Car
Geneva, 4-5 March 2009
2
Motivation
3
o Automobile accidents in Europe
•
•
•
•
1,300,000 accidents
40,000 dead persons per year (2005)
1,700,000 casualties
160 bn. € economic damage
o „eSafety― concept from the European Union
• Half number of dead persons until 2010
• Passive safety systems reducing the severity of the
accident are not enough
• Target is only reachable with active safety systems
that completely prevent accidents
o Traffic efficiency
o Infotainment services for driving comfort
*Photos from EU PReVENT project
The Fully Networked Car
Geneva, 4-5 March 2009
Introduction
o Spectrum regulation
worldwide
• 5.9GHz DSRC
o Standardization efforts
• EU C2C-CC
• IEEE WAVE
• ITU CALM
o Projects
• EU projects
— CVIS, PReVENT, eSafety,
SEVECOM,
• German national
projects
— AKTIV, FleetNet, NOW,
SIM-TD
The Fully Networked Car
Geneva, 4-5 March 2009
4
Car-to-Car Communication
o
5
Spectrum for ITS in Europe
• Aug. 2008
• 30 MHz at 5.9 GHz (5.875GHz – 5.905GHz)
o
Wireless Access in Vehicular Environments (WAVE)
• Physical layer (PHY)
— 10MHz channel at 5.9GHz ITS band
— IEEE 802.11p (802.11a, OFDM)
IEEE P1609.1
WAVE Resource Manager
• Medium Access Control (MAC)
— Basic IEEE 802.11 MAC
— CSMA/CA
— MAC-X IEEE P1609.4
• Upper layers
IEEE P1609.3
Networking Services
WAVE
Management
Entity
— IEEE 1609.x
o
Services
•
•
•
•
Wireless local danger warning
Cooperative danger warning
Traffic information dissemination
P2P file sharing
The Fully Networked Car
Geneva, 4-5 March 2009
IEEE P1609.4
Multi-channel Operations
(MAC Extension)
MLME
IEEE 802.11p
WAVE MAC
PLME
IEEE 802.11p
WAVE PHY
IEEE P1609.2
Security Services for
Applications and
Management Messages
MLME:
MAC Layer
Management Entity
PLME:
Physical Layer
Management Entity
Simulation Study of C2C Communication
Performance
o Maneuvering assistance
• Periodical information
exchange among
neighboring vehicles
• Information update
frequency 10 Hz
o Interested metrics
• Information Update
Interval
• Channel Busy Time
Neighborhood Map
Of Host Vehicle
Dint
......
......
......
......
......
......
Host
Vehicle
......
......
......
......
......
......
Parameter
Low Density
High Density
Average Inter-vehicle Distance (Dint)
80 m
10 m
Average Vehicle Speed
160 km/h
20 km/h
Market Penetration Rate
100%
100 %
PHY Mode
BPSK ½ (3 Mb/s)
BPSK ½ (3Mb/s)
Hazard Warning Packet Size
100 B
100 B
Manoeuvring Message Frequency
10 Hz
10 Hz
Warning Message Priority
VI (AC2)
VI (AC2)
Transmit Power Level
20 dBm
20 dBm
The Fully Networked Car
Geneva, 4-5 March 2009
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Performance: Maneuvering Assistance
With 100% penetration rate, WAVE system works well in both low and high
density scenarios
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
High density scenario
Probability ( Update Interval < x)
Low density scenario
Probability ( Update Interval < x)
o
7
WAVE Random Start
WAVE Rebroadcast
50
Broadcast
Algorithm
100 150 200 250
Update Interval x (ms)
CBL
(%)
300
350
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
WAVE Random Start
WAVE Rebroadcast
50
100 150 200 250
Update Interval x (ms)
Update Interval
300
350
Update Interval
Max
Min
Mean
(ms)
(ms)
(ms)
Standard
Deviation
Broadcast
Algorithm
CBL
(%)
Max
Min
Mean
(ms)
(ms)
(ms)
Standard
Deviation
WAVE Random
Start
12
330.5
52.2
104.3
31.6542
WAVE
Random Start
35
313.0
53.6
106.5
33.0032
WAVE
Rebroadcast
13
209.8
18.1
102.4
23.2994
WAVE
Rebroadcast
42
225.5
9.4
84.1
36.8479
The Fully Networked Car
Geneva, 4-5 March 2009
Performance: Message Propagation with Low
Penetration Rate
o With low penetration rate, the vehicular ad-hoc
network suffers from fragmented network problem
o Message propagation
relies on vehicles on the
opposite direction
o The end-to-end delay
depends on the network
density and market
penetration rate
P(  t )  1  e tr ( 2 R  vtr t ru ) , t 
ru  2 R
vtr
Comm. Range: R=250m
Speed: vtr=85km/h
Vehicle density: λtr=29 Vehicle/km
Distance to go: ru=1000m
The Fully Networked Car
Geneva, 4-5 March 2009
[1] Schoenhof, M., et al, Coupled Vehicle and information flows: Message
transport on a dynamic vehicle network, Physica A, Apr., 2006. p73-81
8
Cooperative Cars – CoCar
o
German BMBF funded research project
• basic research for V2V and V2I communication using cellular mobile
communication technologies
• Consortium
— Ericsson (project leader), Vodafone, Daimler, MAN, Volkswagen
o
Cellular technologies (GPRS, UMTS, HSPA, LTE) (HSPA = HSDPA+HSUPA)
• Sufficient coverage
• Increasing data rate and capacity
• Improved Latency
o Services
• Safety
• Infotainment
The Fully Networked Car
Geneva, 4-5 March 2009
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100
90
80
70
60
50
40
30
20
10
0
0
C.D.F. [%]
C.D.F. [%]
Performance of Cellular System (UMTS) for
Vehicular Applications
o
o
Infrastructure ensures timely message
dissemination throughout large areas
Broadcast enables efficient message dissemination
for many-user scenario
End-to-end delays of below 500 ms can be
achieved using in today’s UMTS networks, but not
guaranteed
*) Results from [2] S. Sories, J. Huschke, M.-A. Phan, Delay Performance of Vehicular Safety
Applications in UMTS, 15th World Congress on ITS, New York, 2008
The Fully Networked Car
Geneva, 4-5 March 2009
100
90
80
70
60
50
40
30
20
10
uplink
0
downlink
0
total
a) Cell_DCH State
50
100
150
200
c) Cell_FACH
State
Delay [ms]
100
200
300
d) IdleDelay
State [ms]
400
500
C.D.F. [%]
o
100
90
80
70
60
50
40
30
20
10
0
0
10
2000
4000
Delay [ms]
6000
Cellular System vs. C2C
Cellular (UMTS)
Network infrastructure
Communication range
System Capacity
11
C2C (WAVE)
Infrastructure based system
Infrastructure-less system, but some
services require infrastructure support
Infrastructure ready
No infrastructure ready in Europe
Network coverage range
Ad-hoc network with single hop distance of
300 m-1 km
Interference limited system with limited Scalable adaptive ad-hoc network
resource of each cell
Minimum end-to-end delay around 100 ms Minimum end-to-end delay < 100 ms for
(HSPA) for local hazard warning service, local hazard warning guaranteed
but not guaranteed
Processing/network Delay
Delay performance
communication
is
penetration rate
Licensed spectrum
Cost
Security and anonymity
The Fully Networked Car
Geneva, 4-5 March 2009
of long distance Without
supports
from
roadside
independent
of infrastructure, the delay performance of
long distance communication depends on
the penetration rate
Cost-free spectrum
Well developed network reduces the cost Huge investment is expected in deploying
of developing and maintaining the and maintaining dedicated roadside
infrastructure
infrastructure, if there will be any WAVE
roadside infrastructure
Centralized
: Pros
: Cons
Distributed
infrastructure
protocol
relying
on
Hybrid Solution with Cellular and C2C
12
o Shared application module
o Parallel WLAN and cellular
communication modules
o Infrastructure support
from cellular system
o Time critical applications
through C2C
Memory
Main
Processor
UMTS/LTE
Radio Unit
WAVE Radio Unit
(5.9 GHz)
GPS Unit
Comm.
Manager
Host
Vehicle
Position
The Fully Networked Car
Geneva, 4-5 March 2009
Vehicle
Bus
Host vehicle
speed,
acceleration,
etc.
Safety
Application
Logic
Warning/Info.
Non-Safety
Application
Logic
Human
Machine
Interface
RNC
GGSN
TIS
Conclusion
o Car2Car:
• With high penetration rate, Car2Car system works
well
• With low penetration rate, VANET suffers from
fragmented network problem
o Cellular:
• Infrastructure ensures timely message
dissemination throughout large areas
• Infrastructure already in place
• Weak on very time critical safety applications
o The hybrid solution combines benefits of both
technologies
The Fully Networked Car
Geneva, 4-5 March 2009
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14
Thanks for your attention!
Yunpeng Zang
zyp@comnets.rwth-aachen.de
Sabine Sories
sabine.sories@ericsson.com
http://www.aktiv-online.org/
The Fully Networked Car
Geneva, 4-5 March 2009