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Vehicle-to-Vehicle Wireless Communication Protocol for

Collision Warning

Arunkumar AnandNo 2, S7 ECE

http://arunkumaranand.bizhat.com/seminar

Seminar Presentation 2006Dept. of Electronics & Communiactions.

Govt. Engg. College, Wayanad.

28th September 2006

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Contents

• 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

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’ perceptionLine-of-sight limitation of brake lightLarge processing/forwarding delay for emergency events.

Accidents have been taking thousands of lives each year

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1. Line of Sight Limitation

What’s in front of What’s in front of that bus ?that bus ?

What’s behind What’s behind the bend ?the bend ?

On rainy daysOn rainy days

On foggy daysOn foggy days

Constraints of human drivers’ perception

Fig.1

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2. Large forwarding delay for emergency events.

Constraints of human drivers’ perception

Three Cars, namely

Car A

Car B

Car C

Reaction time ranges from 0.7sec to 1.5sec

Animation. 1

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Data Base

Traffic Management Center(TMC)

CommunicationHot Spots (DSRC)

Satellite toVehicle(GPS)

Vehicle-to-

Vehicle

( DSRC)

Vehicle -

to-

Roadside(DSRC)

Overview of Different Vehicular Communications

Petrol Pump, Workshop etc..

( V2V )

( V2R )

Scope of this Paper

Fig.2

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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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for a vehicle participating in V2V communication

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

Needs and Assumptions

Interested on Direction, Speed, Position etc…

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Protocol for Vehicular Comm.

Unreliable wireless link Congested channel Versatile topology due to high mobility of vehicles Low Latency Dynamically form wireless loops

Challenges and Requirements

Technology for ITS especially for v2v and v2r communicationService rules for DSRC are developed by the ASTM DSRC is based on IEEE 802.11a technology

10mMin. Separation

1000mMax Range

1-54MbpsData Rate

7 channelsChannels

QPSK OFDMModulation

75MHz (5.850 – 5.925GHz)Bandwidth

DSRC (Dedicated Short Range Communication)

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DSRC for cooperative vehicle information

positionspeedintent…

Analyze a practical situation

Animation. 2

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DSRC for cooperative vehicle information

positionspeedintent…For me!

Not For me!

Who affects the most ?

Animation. 2

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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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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

Application Challenges <1>

Fig.3

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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

Fig.4

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Eliminate redundant EWMs

State transitions of AVs

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.

Flagger AV: resuming EWM transmissions at the minimum required rate.

Non-flagger AV: nonparticipating in sending EWMs to the group on some conditions to eliminate redundant EWMs

Each AV may be in one of three states:

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State transitions of AVs (condition.)

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 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 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. 5c

Fig. 5b

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Examples of state transitions (cont.)

Fig. 5d

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Future Works

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

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

USDOT Intelligent Transportation Systems (ITS) Program

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HiBuddy

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.

Conclusion

An Overview of Vehicular Comm. is given.

Protocol of Vehicular Comm. Is discussed.

Protocol Challenges are also analysed.

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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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