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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
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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
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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
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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
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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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II. Previous Studies on VANET Broadcast Protocols
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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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II. Previous Studies on VANET Broadcast Protocols
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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
II. Previous Studies on VANET Broadcast Protocols
Segment 1Segment 2Segment 3Segment 4Segment 5
[0,7][8,15][16,23][24,31][32,39]
ACKCTB
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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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II. Previous Studies on VANET Broadcast Protocols
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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)
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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
III.Multi-behavior and Reliable Broadcast (MRB) Protocol (2/9)
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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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III.Multi-behavior and Reliable Broadcast (MRB) Protocol (3/9)
MRB Reliable Approach
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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 )
III.Multi-behavior and Reliable Broadcast (MRB) Protocol (4/9)
MRB Reliable Approach
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
MRB Reliable Approach
III.Multi-behavior and Reliable Broadcast (MRB) Protocol (6/9)
Segment1Segment 2Segment 3
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davg
LiLf
abnor mal
vehicle
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III.Multi-behavior and Reliable Broadcast (MRB) Protocol (8/9)
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.
III.Multi-behavior and Reliable Broadcast (MRB) Protocol (9/9)
MRB Dissemination Approach
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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
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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
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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
L a t e n c y ( Q s )
Headway (sec)
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MRB Dissemination Approach, UMB and SB Protocols Comparison
L a t e n c y ( Q s )
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
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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