Improving Reliability of Platooning Control Messages Using Radio and Visible Light Hybrid Communication
Susumu Ishihara (Shizuoka University)
Vince Rabsatt, Mario Gerla (UCLA)
Platooning
• Autonomous Platooningor Cooperative Adaptive Cruise Control (CACC) • Improves the traffic flow• Reduces the fuel consumption• Improves the drivers’ safety
2
To the direct follower
Camera/RADAR/
LIDAR,etc.
Leader to followers
Sartre (EU)-2012
http://www.nedo.go.jp/activities/FK_00023.html
Energy ITS (Japan) -2013
1Truck and 3 cars Demo 6m gap @90km/h 5.9GHz DSRC 40Hz Message
4 Truck-Demo 4.7m gap @80km/h 5.8GHz DSRC + IR 50Hz Message
http://www.sartre-project.eu/en/about/news/Sidor/roadtrains_video.aspx
Recent Platooning Projects
3
4
Adaptive Cruise Control (ACC) Uses information of the preceding car
Cooperative Adaptive Cruise Control (CACC) Uses information of the preceding car and the leader car
Simulation of Platooning on Scenargie1, a discrete event simulator(Same scenario provided with plexe2, a platooning extension for Veins)
[1] Product of Space-Time Engineering, https://www.spacetime-eng.com/[2] Michele Segata, Stefan Joerer, Bastian Bloessl, Christoph Sommer, Falko Dressler and Renato Lo Cigno,
"PLEXE: A Platooning Extension for Veins," IEEE VNC 2014
Many issues for realizing platooning
• Control Theory • Vehicle Dynamics • Communications • Sensing • Image Processing • Localization • Traffic Engineering • etc.
5
Communication Issues• Radio Communication Capacity
• If many vehicles are on the road, radio communication capacity may be exhausted.• Communication Rate Control• Transmission Power Control
• Security • What if attackers make a radio signal jam? • What if a malicious vehicle pretends other cars?• What if a malicious vehicle generates wrong update
information?
6
Fragile Radio Communication
• If there is a malicious machine that sends a jam signal, messages transmission from the leader vehicle can be easily damaged.• We can easily make jamming machine using
software radio platforms, such as GNU Radio/USRP, WARP, etc.
• This is a potential problem of CACC based on radio communications.
Slow down
7What if we use Visible Light Communication?
Contributions of this paper• We proposed an RF and VLC hybrid communication
protocol for platooning control messages for reliable message delivery under RF jamming attacks.
• We developed a simulation model supporting both radio communication and VLC on Scenargie
• The proposed protocol works effectively to decrease the end-to-end delay of the leader messages and improve the message delivery ratio under jamming attack
8
Simulation: Effect of jamming attack
Jam part is 802.11p Compliant PLCP Preamble + PLCP Header + Part of MAC Header
Jam
64us 10us
10~400us
Jam Jam Jam Jam Jam
Jam Jam
[Punal2015] Periodic Jammer
Our simulation
on Scenargie
10~400us Jam
CBR Broadcast on IEEE 802.11p 6Mbps
(Payload 300bytes / 10Hz)
J
S R
ds dr
dsr: 10m and 50m
Jammer
Tx Power 20dBm
Tx Power 20dBm
9
Simulation Results: Packet Delivery Ratio under Jamming Attack
Dist(S, R) = 10m
10us 120us 150us 200usIdle duration of Jam signal 122us
75m65m 65m
• If the idle duration is long, the sender can find the channel idle state longerthan DIFS (=58us) + Backoff. Thus, the sender can send a frame.
• But if the distance between the sender and the receiver is long,due to the bad SINR, the receiver cannot decode the frame.
15m75m
Dist(S, R) = 50m
Color = Packet Delivery Ratio
Dist(Source, Jammer)
Dist(Receiver, Jammer)
15m75m
10
Using Visible Light Communication (VLC)
• Uses LED lights for communication between adjacent vehicles • Cheap – Low Additional Equipment Cost
• Every vehicle has tail lights and head lights.• Difficult to attack - Highly directional
• VLC jammer has to be in the field of view of the receiver device to attack• Jamming light has to be concentrated to the receiver device
• But, long distance communication over multiple vehicles is difficult • Multi-hop communication is needed – Long message delivery delay
11
Shortening message delivery delay
• Hybrid of RF Communication and VLC
• RF • Wide range – Propagates beyond multiple vehicles• Vulnerable to Jamming
• VLC • Short range – Hop by hop communication• Strong against Jamming
12
Radio and VLC Hybrid Message Delivery for Platooning
RF Broadcast
LeaderVLC• Leader sends a message via both VLC and RF interfaces
• If a vehicle receives a new message from either of VLC and RF interfaces, it forwards the message via VLC (and RF).
• Only If a condition is satisfied, the vehicle forwards the message via both VLC and RF to avoid RF channel congestion.
13
RF Broadcast
Condition for forwarding a message via RF
• Candidates of conditions • Distance from the previous RF hop vehicle• Elapsed time from the transmission by the leader• Number of hops from the leader• SINR of the signal from previous radio-hop vehicle• etc.
14
In this simulation: “If a new leader message arrives from VLC, forward it via RF and VLC.”
Intuition: If an RF message does not arrive, the leader may be suffering jamming attack and cannot send the message. Thus other vehicles have not received the message. …. RF broadcast is needed.
Simulation Model
15
30°
RF IEEE802.11p Interface (6Mbps, AC_VI) Omni antenna: 5.9GHz
VLC interfaces with a directional antenna model Comm. range: 5m (the same as the inter vehicular distance) MAC: ALOHA Bitrate: 50kbps (assuming cheap off-the-shelf devices)
Note: This model is just an abstract model of VLC. It does not simulate realistic visible light propagation.
5m
We implemented multiple interfaces with different antenna models (pos. and direction) and an application model using these interfaces on Scenargie
Simulation Scenario
16
500m10m
10m
…
t=010 vehicles
10m
…
Periodic Jammer
…
5m
12.5m
17.0m/s
• Jammer: Periodic Jammer [64us JAM and 10us idle period] • Platoon of 10 vehicles: 1 platoon scenario and 4 x 4 platoon scenario • Leader sends 200byte message to the members every 0.1sec. • Tx power of All vehicles and Jammer: 20dBm • Propagation: Free Space, Fading: Nakagami
Compared Strategies
17
Use VLC Use RF Forwarding
Forward only when receiving a new
message via VLC
Only Direct RF (FFF) F F F
RF Forward (FTF) F T F
VLC + No RF Fwd. (TFF) T F F
VLC + unconditional RF Fwd. (TTF) T T F
VLC + conditional RF Fwd. (TTT) T T T
End-to-End delay at 5th car / 1platoon
18
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 7. Time series variation of end to end delay of leader messages(1 platoon)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 8. Time series variation of end to end delay of leader messages (4× 4platoons)
Longblind period (4sec.)
Only Direct RF (FFF)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 7. Time series variation of end to end delay of leader messages(1 platoon)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 8. Time series variation of end to end delay of leader messages (4× 4platoons)
Long delay
Blind period (2sec.)
RF Fwd. (FTF)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]Time [sec]
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 7. Time series variation of end to end delay of leader messages(1 platoon)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 8. Time series variation of end to end delay of leader messages (4× 4platoons)
VLC + No RF Fwd. (TFF)
VLC’s multi-hop delay
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 7. Time series variation of end to end delay of leader messages(1 platoon)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 8. Time series variation of end to end delay of leader messages (4× 4platoons)
Long delay period is shortened
VLC+unconditional RF Fwd. (TTF)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 7. Time series variation of end to end delay of leader messages(1 platoon)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 8. Time series variation of end to end delay of leader messages (4× 4platoons)
VLC + conditional RF Fwd. (TTT)
No positive effect of conditional RF Fwd.
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 7. Time series variation of end to end delay of leader messages(1 platoon)
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a1) 5th car False/False/False (b1) 10th car False/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a2) 5th car False/True/False (b2) 10th car False/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a3) 5th car True/False/False (b3) 10th car True/False/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50En
d-to
-end
del
ay [s
ec]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a4) 5th car True/True/False (b4) 10th car True/True/False
0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec] 0
0.5
1
1.5
2
2.5
20 25 30 35 40 45 50
End-
to-e
nd d
elay
[sec
]
Time [sec]
(a5) 5th car True/True/True (b5) 10th car True/True/True
Fig. 8. Time series variation of end to end delay of leader messages (4× 4platoons)
VLC
VLC+RF
5th car/1platoon 10th car/1platoon 5th car/ 4 x 4 platoons
10th car/ 4 x 4 platoons
Other cars / Many platoons cases
20
0
2
4
6
8
10
20 25 30 35 40 45 50
Pack
et d
eliv
erie
d in
1 s
ec
Time [sec]
False/False/FalseFalse/True/FalseTrue/False/FalseTrue/True/FalseTrue/True/True
(a) 5th car / 1 platoon
0
2
4
6
8
10
20 25 30 35 40 45 50
Pack
et d
eliv
erie
d in
1 s
ec
Time [sec]
False/False/FalseFalse/True/FalseTrue/False/FalseTrue/True/FalseTrue/True/True
(b) 10th car / 1 platoon
0
2
4
6
8
10
20 25 30 35 40 45 50
Pack
et d
eliv
erie
d in
1 s
ec
Time [sec]
False/False/FalseFalse/True/FalseTrue/False/FalseTrue/True/FalseTrue/True/True
(c) 5th car / 4× 4 platoons
0
2
4
6
8
10
20 25 30 35 40 45 50
Pack
et d
eliv
erie
d in
1 s
ec
Time [sec]
False/False/FalseFalse/True/FalseTrue/False/FalseTrue/True/FalseTrue/True/True
(d) 10th car / 4 platoons
Fig. 9. Packet delivery ratio
By forwarding beacon messages using RF at each membervehicle (FTF, (a2) (b2)), the number of beacon messagesreceived by the members increases, but the end-to-end delayis long and the number of received messages during a fewseconds when the vehicle at the closest point of the jammer.If the leader vehicle cannot send any beacon message due tothe busy state of the RF channel caused by the jammer, thefollower vehicle cannot forward the beacon message, thus thepacket received by the member vehicles is still small.
By using only VLC for forwarding beacon message ofthe leader vehicle (TFF (a3), (b3)), the reachability of thebeacon messages improves. It can be confirmed clearly inFig. 9. However, the end-to-end delay is long for long duration,especially when the position of the vehicle in the platoon isbackward and the number of platoons is large.
Using both RF and VLC for forwarding beacon messages ofthe leader (TTF, (a4), (b4)), the duration of end-to-end delayis shortened. When using the forward via RF only if VLS isfaster strategy (TTT, (a5) ,(b5)), due to the smaller number ofRF forwarding messages caused by the strategy, the end-to-enddelay is longer than TTF case when the number of platoon is1. The idea behind the strategy is to prevent congestion causedby the messages forwarded by member vehicles under RFjamming attacks. Thus, the effect of the strategy is expected topresent when the number of vehicles/platoons is large. Whenthe number of the platoon is 16 (Fig. 8), the difference betweencases of TTF and TTT is very small. We cannot see neithernegative impact nor positive impact of the forward via RF onlyif VLS is faster strategy in this case.
Note that in the simulation of in this paper, we assumedvery slow VLC link (50kbps) that will be realized by today’soff-the-shelf LED and photo-diode devices. The delay factor ofthe system strongly is dependent on the link speed. To balancethe requirement of the end-to-end delay that the platooningalgorithm requires and the link speed and technology used inVLC should be carefully chosen.
VI. CONCLUSION
We proposed a radio and visible light hybrid protocolfor improving the reliability of control message used in au-tonomous platooning systems and evaluated the effectivenessof the strategies through simulations. The simulation resultsshow that by using both radio communication and multi-hop visible-light communication, the reliability of platooningcontrol messages from the leader vehicle can be significantlyimproved and the end-to-end delay can be shortened. Futurework will be more simulation with realistic scenarios thatinclude the real platoon mobility and precise VLC commu-nication model including the interference of VLC signals,especially in congested and/or curved lanes.
ACKNOWLEDGMENT
This work is supported by KAKENHI 15H02689.
5th car
10th car
1 platoon
# of new messages delivered in 1sec.
FFF
FTF (RF Fwd.)
TTF TTT
TFF
with VLC
Why packet delivery ratio < 1 with VLC?
Leader Member
RF
VLCGap
Conclusion• We proposed an RF and VLC hybrid
communication protocol for platooning control messages for reliable message delivery under RF jamming attacks.
• Findings • Long blind under a jamming attack only with RF.• RF + VLC Hybrid communication can better message
delivery ratio and short delay
• Future work • Effect of different communication speed of VLC• Effect of RF jamming on the dynamics of platoons• VLC jamming attack
21
Thank you
Top Related