Introduction Nowadays, vehicles have become an indispensable part of modern life. Inter-Vehicle Communication (IVC) has attracted considerable attention from both academia and industry. IVC is a powerful tool for promoting road safety and commercial applications in vehicular ad hoc networks (VANets). One of the primary applications of IVC is the provision of road traffic information. Traffic jams to emergency vehicles such as ambulances, fire engines, police vehicles, paramedics.
TrafficGather: An Efficient and Scalable Data Collection
Protocol for Vehicular Ad Hoc Networks
Wang-Rong Chang
Department of Electrical Engineering, National Cheng Kung
University, Taiwan
Hui-Tang Lin, Bo-Xuan Chen
Institute of Computer and Communication Engineering, National
Cheng-Kung University, Taiwan
IEEE Consumer Communications & Networking Conference ( CCNC
) 2008
Outline
IntroductionOverviewTrafficGather Data Collection
ProtocolSimulationConclusions
Introduction
Nowadays, vehicles have become an indispensable part of modern
life.
Inter-Vehicle Communication (IVC) has attracted considerable
attention from both academia and industry.IVC is a powerful tool
for promoting road safety and commercial applications in vehicular
ad hoc networks (VANets).
One of the primary applications of IVC is the provision of road
traffic information.Traffic jams to emergency vehicles such as
ambulances, fire engines, police vehicles, paramedics.
Introduction
Recently, many researchers have proposed IVC Medium Access
Control (MAC) protocols for vehicular ad hoc networks
(VANets).Self-organizing scheme
Self-organizing schemevehicles can subdivides the road on
demandeach cluster-head collect data in cluster each cluster-head
can negotiate the traffic information each other
the direction of vehicles
i
cluster 1
cluster 2
collision
Introduction
In the scheme, the data collection will suffer from many message
collision.
i
the direction of vehicles
i
Introduction
the paper proposed a efficient data collection protocol for
VANET.To avoid the message collisionsTo reduce the message
collection time
i
Network Assumptions
Each vehicle equips a GPS and digital map.Minimum vehicle length
is Ls meters. Each vehicle communication range is R.The number of
lanes is M.
Overview
A
RM
When Vehicle A want to acquire traffic information, the Vehicle
A will broadcast the Request Message (RM).
B
C
D
E
F
G
H
I
J
the direction of vehicles
Overview
RM
The RM will be forwarded by vehicle which is downstream
direction and the farthest from the source
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
Overview
RM
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
The RM will be forwarded by vehicle which is downstream
direction and the farthest from the source
Overview
To find the appropriate cluster-head candidates among the
vehicles and then to subdivide the network into a series of
contiguous cluster.
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
Cluster 0
Cluster 1
CV 0
RV 0
CV 1
CV: Cluster-head Vehicle
RV: Relay Vehicle
Overview
A
B
C
D
I
J
the direction of vehicles
Cluster 0
CV 0
A Road Section
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
To avoid the message collisions
Overview
A
B
C
D
I
J
the direction of vehicles
Cluster 0
CV 0
A Road Section
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
1
2
3
4
5
6
7
8
9
10
11
12
13
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15
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21
TrafficGather Data Collection Protocol
Phase I: Network Configuration PhaseClustered organization
schemeOrganization termination scheme
Phase II: Data Collection PhaseIntra-Cluster Space DivisionTDMA
access control algorithmCluster synchronization scheme
Phase III: Data Retrieval Phase
Phase I: Network Configuration Phase
Clustered organization scheme
Request Message
Indicate the RM broadcasted by a CV or a RV
MT = 0: from CV
MT = 1: from RV
Contain the ID of vehicle which is current CV
Indicate the transmission direction of the RM
RM = 01 downstream direction
RM = 10 upstream direction
RM = 11 both direction
GPS position of the CV which issued the RM
MT (1-bit)CV-IDMD (2-bit)GP
Phase I: Network Configuration Phase
A
RM
B
C
D
E
F
G
H
I
J
the direction of vehicles
CV 0
When Vehicle A want to acquire traffic information, the Vehicle
A will broadcast the Request Message (RM).
0CV 001GPS_A
Phase I: Network Configuration Phase
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
B,C,D RMGPS A downstream directionCluster 0
Phase I: Network Configuration Phase
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
Waiting time threshold = 1/ distance between the position of
itself and the position of CV 0
WM
Phase I: Network Configuration Phase
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
WM
B, C will concede defeat and take no action.
TrafficGather Data Collection Protocol
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
Because vehicle D win the race and MT = 0, the vehicle D become
a RV
RV 0
TrafficGather Data Collection Protocol
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
RV 0
RM
RV 0 reset the RM and forward the RM
1RV 001GPS_D
Phase I: Network Configuration Phase
RM
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
CV 1
CV 1 reset the RM and forward the RM
0CV 101GPS_F
Phase I: Network Configuration Phase
Organization termination scheme
RM
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
RV 1
When G located outside of this data collection range to RM, it
will ignore the RM
Phase I: Network Configuration Phase
Phase I completion
A
B
C
D
E
F
G
H
I
J
the direction of vehicles
Cluster 0
Cluster 1
CV 0
RV 0
CV: Cluster-head Vehicle
RV: Relay Vehicle
CV 1
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
Cluster 0
CV 0
A Road Section
Segment(i) (0
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
Cluster 0
CV 0
A Road Section
Lane(j)
0
1
2
3
4
5
6
0
1
2
Intra-Cluster Space Division
Segment(i) (0
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
Cluster 0
CV 0
A Road Section
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
= i + j * N + 1
Intra-Cluster Space Division
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
CV 0
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
TDMA access control algorithm (TACA)
x
y
GPS
I
CV 0
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
The RV 0 will occur collision
RV 0
1
8
15
CV 0
CV 1
7
Phase II: Data Collection Phase
Cluster synchronization scheme
T is the time index when Phase I terminatedaccording to the
distance
is the collection time for a cluster = M * N * t
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
CV 0
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
The CV 0 will sends a HELLO message to all cluster member to
collect their traffic informations.
HELLO
Phase II: Data Collection Phase
A
B
C
D
I
J
the direction of vehicles
CV 0
Lane(j)
Segment(i)
0
1
2
3
4
5
6
0
1
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
The CV 0 will sends a HELLO message to all cluster member to
collect their traffic informations.
Phase III: Data Retrieval Phase
The current study adopts a flooding strategy to retrieval the
traffic information.
Simulation
Ls = 5 m for all vehiclesVelocity for each vehicle is randomly
generated with a uniform distribution within the interval U[36,
37]Goodput = the number of information messages received by all of
the CVs / the total number of vehicles on the road.
Simulation
Simulation
Conclusions
This paper has presented a data gathering mechanism for VANets
based on a self-organizing cluster networking approach.
The proposed protocol, designated as TrafficGather, achieves
collision-free transmissions and therefore improves the efficiency
and accuracy of gathering the traffic information on the road.
Thank you
(
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