Presentation Mastere Finale

8/3/2019 Presentation Mastere Finale

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A Multi A Multi--behavior behavior and and ReliableReliable BroadcastBroadcast Protocol Protocol of of

Emergency Messages inEmergency Messages in Vehicular Vehicular NetworkNetwork

Supervised by:

M. Tabbane NabilPresented by:

Essaies Meriam



Outline

I. State of the art

II. Previous Studies on VANET Broadcasting

Protocols

III. Multi-behavior and Reliable Broadcast (MRB)

Protocol Design

IV .Simulation Results

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VANET Applications

Safety Applications

Collision warning

Work zone warning

Intersection CollisionWarning

Lane change warning

Rollover warning

Approaching Emergency Vehicle

Non Safety Applications

Electronic Toll Collection

Internet Access

Traffic Information and

recommendation, etc«

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State of the art



High mobility of nodes

High dynamic topology

Critical latency requirements

No prior information about location must be required

No problem with power

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VANET Network Characteristics

State of the art



Broadcasting Protocols

Reliable Protocols Dissemination Protocols

RebroadcastingSelective

ACK

Changing

parameters

Flooding Single Relay

Categories of Broadcasting Protocols

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II. Previous Studies on VANET Broadcast Protocols



Requirements:

Reliability

Minimum collisions

Minimum latency

High dissemination speed

Problems:

No prior information about location must be required

Hidden terminal problem

Different traffic volumes

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Exchanged messages are RTB/CTB/Data/ACK

Urban Multi hop Broadcast (UMB) protocol addresses:

Hidden node problem

Broadcast storm problem

Reliability

RTB/CTB Approach

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Smart Broadcast (SB) Protocol

Source

node

Direction of dissemination

Transmission range = 1000 meters

Number of segments = 5;

Contention window size = 8

1000 meters

200 meters


Segment 1Segment 2Segment 3Segment 4Segment 5

[0,7][8,15][16,23][24,31][32,39]

ACKCTB



Weakness key:

The protocol could end up in multiple iterations

It shows a trivial dependency on the setting of the contention

window size.

Segment length is uniform.

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MRB Characteristics:

Multi behavior protocol

RTB/CTB mechanism

Changing parameters techniques

Acknowledgment techniques

Based on:

Minimization of latency and collision probability.

Both distance and speed

Density 11

III.Multi-behavior and Reliable Broadcast (MRB) Protocol (1/9)



Application Priority Target

Collision warning Critical safety Dissemination

Sudden break warning Critical safety Reliability

Approaching Emergency

VehicleWarning

Critical safety Dissemination

Lane changingWarning Safety Reliability

Pre Crash SensingWarning Safety Reliability

Left Turn Assistant Safety Reliability 12




MRB reliable approach intend to alert the most endangered

vehicle in a limited time.

It introduces Human factors

It uses Non Uniform Time Based Segmentation

The goal is to find the best segmentation points that results in

minimum collision probability in the first segment.

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MRB Reliable Approach



Time headway:

Abnor mal

vehicle (Vi)

D

Time To Collision (TTC)Time To Avoidance (TTA)

Where:

µ is the estimated tire-road friction coefficient,

g is the acceleration of gravity,

Vf is the current speed,

is a speed reduction factor,

Tr is the response time of a driver.

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Following

vehicle (Vf )



f / _ V DheadwayTime !

)/(i f

V V DTTC !



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30 Km/h

60 Km/h

120 Km/h

Segment 1Segment 2Segment 3

Segment 3 Segment 2 Segment 1

30 Km/h

60 Km/h

120 Km/h

Distance Based Segmentation

Tim

e BasedS

egm

entation



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Send un RTB message

including its location and

its current speed.

TTC< TTA + K

And did not respond to the

danger

The nearest in time

and the most

endangered vehicle.

10 sec



Segment1Segment 2Segment 3



davg

LiLf

abnor mal

vehicle

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MRB Dissemination Approach

Where:

N is the number of nodes inside the f irst se g ment

d av g is the avera g e distance between vehicles

L is the number of lanes

Segment 1



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3 cases are possible to occur when nodes enter in contention

phase:

Idle case (I)

Successful broadcasting case (B)

Collision case (C)

Where:

Round denoting the rounding function

N is the number of nodes in the segment

Nopt is the maximum number of nodes in the segment to avoid

unsuccessful CTB broadcast in 1Time Slot.


MRB Dissemination Approach



Key performance indicators:

Latency

Collision probability

Time-Slot 16µs CTB 14 bytes

SIFS 32 µs Messages 512 bytes

DIFS 64 µs ACK 512 bytes

RTB 20 bytes Data rate 3 Mbps

Simulation parameters quoted from WAVE standard

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IV.Simulation Results



C o l l i s i o n p r o b a b i l i t y

Headway (sec) 21

MRB Reliable Approach Collision Probability (330 veh/h)

MRB Protocol Perfor mance



Average latency value in the first

segment is equal to 2880microsecond

L a t e n c y ( Q s )

MRB Reliable Approach Latency (330 veh/h)

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Latency threshold is 5 ms

Headway (sec)

Number of segment is 10



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Latency threshold is 5 ms L a t e n c y (

Q s )

Number of nodes

MRB Dissemination Approach Latency (330 veh/h)



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MRB Reliable Approach, UMB and SB Protocols Comparison


Headway (sec)



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MRB Dissemination Approach, UMB and SB Protocols Comparison


Number of nodes

Latency threshold is 5 ms



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Conclusion

Our contribution is a novel broadcast protocol especially designed for an optimum

performance in Vehicular Environment.

Multi-behavior Reliable Broadcast (MRB) Protocol act differently to each VANET

safety application

MRB proposes two approaches: Reliable and Dissemination approach

MRB reliable approach is used in case of sudden break, lane change, etc

MRB dissemination approach is used in case of vehicle crashes, or emergency vehicle

approaching warning

MRB process with high performance



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Future Perspectives

In this work:

Determine the best number of segments and the best number of potential nodes for a traffic

condition

How to assure an effective broadcast in case where there is a huge gap between clusters

In f uture works:

Routing protocol to alert the nearest emergency vehicle.

Reactive algorithm based on contention window changing.

Vertical HO between IEEE 802.11 p andWIMAX

Security



THANKS

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Q1: Calculating the delayQ1: Calculating the delayy Contention starting time:DIFS + RTB

y Success broadcasting time:SIFS + CTB + SIFS + DATA + SIFS + ACK

y Collision time:SIFS + CTB + SIFS

y

Waiting time: a single time slot.

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SIFS

DIFS

SIFS

SIFS

RTB

CTB

DATA

ACK

Source

Destination

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