Transcript A Vehicle-to-Vehicle Communication Protocol for

Vehicle-to-Vehicle Wireless
Communication Protocol for
Collision Warning
Arunkumar Anand
No 2, S7 ECE
Seminar Presentation 2006
Dept. of Electronics & Communiactions.
Govt. Engg. College, Wayanad.
http://arunkumaranand.bizhat.com/seminar
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28th September 2006
Contents
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Motivation
Application Levels
Overview of Vehicular Communications
Needs and Assumptions
Protocol for Vehicular Comm.
Application Challenges
State Transition
Future Works
Conclusion
References
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Motivation
Accidents have been taking thousands of lives each year
Study shows - “About 60% roadway collisions could be
avoided if the operator of the vehicle was provided
warning at least one-half second prior to a collision”
(- US. Patent No. 5,613,039)
Constraints of human drivers’ perception
Line-of-sight limitation of brake light
Large processing/forwarding delay for emergency
events.
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Constraints of human drivers’ perception
1. Line of Sight Limitation
On foggy days
What’s in front of
that bus ?
What’s behind
the bend ?
On rainy days
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Fig.1
Constraints of human drivers’ perception
2. Large forwarding delay for emergency events.
Reaction time ranges from 0.7sec to 1.5sec
Three Cars, namely
Car A
Car B
Car C
Animation. 1
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Overview of Different Vehicular Communications
Data Base
Scope of
this Paper
Communication
Hot Spots (DSRC)
Petrol Pump,
Workshop etc..
Satellite to
Vehicle
(GPS)
( V2V )
VehicletoVehicle
( DSRC)
Vehicle toRoadside
(DSRC)
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Traffic Management Center
(TMC)
( V2R )
Fig.2
Application Levels
Traffic Safety can be improved if drivers have the ability to
see further down the road.
If traffic information was provided to Drivers, Police and other
Authorities; roads would be safe and traveling on them would
be more efficient
Vehicle-to-Vehicle(V2V) and Vehicle-to-Roadside(V2R)
Communication can bring out the following achievements.
Presence of obstacles on road.
Emergency Braking of a preceding vehicle.
Information about Blind Crossing, School proximity, Railway crossing etc…
Entries to Highways.
High Speed Internet Access.
Electronic Toll Collection.
Parking Space locater in Cities.
Nearest Petrol Pump, Workshop etc..
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Needs and Assumptions
for a vehicle participating in V2V communication
Interested on Direction, Speed, Position etc…
Is able to obtain its own geographical location
and determine the relative positions on the
road.(Digital Maps, GPS)
Is equipped with at least one wireless transceiver
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Protocol for Vehicular Comm.
Challenges and Requirements
Unreliable wireless link
Congested channel
Versatile topology due to high mobility of vehicles
Low Latency
Dynamically form wireless loops
DSRC (Dedicated Short Range Communication)
Technology for ITS especially for v2v and v2r communication
Service rules for DSRC are developed by the ASTM
DSRC is based on IEEE 802.11a technology
Bandwidth
75MHz (5.850 – 5.925GHz)
Modulation
QPSK OFDM
Channels
7 channels
Data Rate
1-54Mbps
Max Range
1000m
Min. Separation
10m
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Animation. 2
Analyze a practical
situation
position
speed
intent…
DSRC for
cooperative vehicle
information
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Animation. 2
Who affects the
most ?
Not For
me!
DSRC for
cooperative vehicle
information
For me!
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position
speed
intent…
Terms
Abnormal Vehicle (AV)
A vehicle acts abnormally, e.g. deceleration
exceeding a certain threshold, dramatic change of
moving direction, major mechanical failure, etc.
Emergency Warning Messages (EWM)
Messages generated by an AV to warn other
surrounding
vehicles,
which
include
the
geographical location, speed, acceleration and
moving direction of the AV.
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Application Challenges <1>
 Requiring to support multiple co-existing
AVs over a longer period of time
Co-existing AVs: AVs whose existences overlap in time and
whose transmissions may interfere with each other
An AV can exist for an extended period of time
Chain effects of emergency road situation
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Fig.3
Application Challenges <2>
 Differentiation of emergency events and
elimination of redundant EWMs
Unnecessary EWMs should be avoided so that the
channel bandwidth can be better utilized for useful
EWMs
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Fig.4
Eliminate redundant EWMs
State transitions of AVs
Each AV may be in one of three states:
Initial AV: When an emergency event occurs to a vehicle, the
vehicle becomes an AV and enters the initial AV state,
transmitting EWMs following the rate decreasing algorithm.
Non-flagger AV: nonparticipating in sending EWMs to the
group on some conditions to eliminate redundant EWMs
Flagger AV: resuming EWM transmissions at the minimum
required rate.
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State transitions of AVs (condition.)
 Transitions from Initial AV state to Non-flagger AV state:
At least Talert duration has elapsed since the time when the vehicle
became an initial AV.
EWMs from one of the “followers” of the initial AV are being
overheard;
 Transitions from Non-flagger AV to flagger AV
sets a timer for a Flagger Timeout ( FT) duration. If it does not
receive any EWMs from its followers when the FT timer expires, the
non-flagger AV changes its state to flagger AV.
Transitions from flagger AV to Non-flagger AV
If a flagger AV receives EWMs from one of its followers, it will
relinquish its flagger responsibility, becoming a non-flagger AV.
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Examples of state transitions
Fig. 5a
Fig. 5b
Fig. 5c
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Examples of state transitions (cont.)
Fig. 5d
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Future Works
USDOT Intelligent Transportation Systems (ITS) Program
Vehicle manufacturers would install the technology in all new vehicles,
beginning at a particular model year
Full-scale deployment in both the vehicles and the roadside
infrastructure will be made by 2008/9
Car2Car Communication Consortium ( www.car-to-car.org )
Non-profit organization initiated by European vehicle manufacturers.
To create and establish an open European industry standard for
Car2Car communication systems based on wireless LAN components
and to guarantee European-wide inter-vehicle operability
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Conclusion
An Overview of Vehicular Comm. is given.
Protocol of Vehicular Comm. Is discussed.
Protocol Challenges are also analysed.
Hi
Buddy
A new era is arriving where vehicles will
communicate with each other, the devices within them, and
also with the world; making the next generation of vehicles
into communication hubs.
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References
[1] S. Biswas, "Vehicle-to-Vehicle Wireless Communication Protocols for Enhancing
Highway Traffic Safety," Communications Magazine, IEEE Publication Date: Jan.
2006 Volume: 44, Issue: 1 page(s):74- 82
[2] X. Yang et al., " A Vehicle-to-Vehicle Communication Protocol for Cooperative
Collision Warning,"Proc. 1st Annual Int’l. Conf. Mobile and Ubiquitous Syst:
Networking and Services, 2004
[3] G.S Bickel, "Inter/Intra-Vehicle Wireless Communication" at
http://userfs.cec.wustl.edu/~gsb1/index.html
[4] Q. Xu, R. Sengupta, and D. Jiang, "Design and Analysis of Highway Safety
Communication Protocol in 5.9 GHz Dedicated Short-Range Communication
Spectrum," Proc. IEEE VTC, vol. 57, no. 4, 2003, pp. 2451–55
[5] C.Bettstetter "Toward Internet-Based Car Communications: On Some System
Architecture And Protocol Aspects" TUM, Germany
[6] J. Zhu and S. Roy, "MAC for Dedicated Short Range Communications in
Intelligent Transport Systems,"IEEE Commun. Mag., vol. 41, no. 12, 2003
[7] http://www.car-to-car.org/
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