Manuela Vieira
Manuel Augusto Vieira
Paula Louro
Pedro Vieira
1
• FCT – ref. UID/EEA/00066/2013
• IPL/2017/EmGraph/ISEL
• IPL/2017/SMART_VeDa/ISEL.
ACKNOWLEDGEMENTS
Vehicular communications using V L C:
Future trends and applications
Lisbon
SENSORCOMM 2018
September 16, 2018 to September 20,
2018 - Venice, Italy
Keynote Speech
Manuela Vieira was born in Lisbon, Portugal. In 1986 she received the Master of Science in Solid State Physics-Microelectronic and in 1993 the PhD in Semiconductor Materials both from the New University of Lisbon. She is a full professor since 2011 in Electronics inside the Department of Electronics Telecommunication and Computers (ISEL- Portugal) and the head of a Group in Applied Research in Microelectronic Optoelectronic and Sensors-GIAMOS in ISEL and another in Microelectronic, Material and processes-(M2P) in CTS-UNINOVA. She has several scientific papers and 30 years of experience in the field of thin films and devices, her research activities have been mainly related to the development of optical sensors .
Other scientific activities:
Referee for international publications such as: Thin Solid Films, Material Research Society, Sensor Magazine, Sensor and Actuators, Material Science Fórum, Solid State Electronics, Vacuum, Applied Surface Science, Sensors and Transducers, Ibersensors, Physica Status Solidi, Sensors, Journal of Nanoscience Nanotechnology, Journal of Sensors, Journal of Signal and Imaging Systems Engineering) Journal of Optical Engineering, Plasmonics, Journal of Luminiscence, etc.
Referee for several EU projects as part of the Programme Growth “Innovative Products, Processes and Organisation“.
Supervision and co-supervision of Master and PhD students
Examiner for Master and Doctoral degrees.
Authored and co-authored more than 350 publications in international journals cited in “Science Citation Index”. Presented more than 500 communications at conferences and seminars most of which with publication in journals and proceedings.
Smart device / Smart Sensor
Intelligent System
System-of-systems
Cognitive collaborative system
Man
ufa
ctu
rin
g
Ene
rgy
Syst
em
s
He
alth
& C
are
Spac
e in
du
stry
Tran
spo
rtat
ion
, Agr
ibu
sin
ess
&
Sm
art
Cit
ies
Technologies & Techniques
Sco
pe
leve
l
Scope:
Smart device/smart sensor
Technologies & techniques:
Electronic systems technology
Application domains:
Smart cities
Location
ISEL-ADEETC
Rua Conselheiro Emídio Navarro, 1
1959-007 Lisboa
Portugal
CTS-UNINOVA FCT Campus
2829-516 Caparica,
Portugal
4
Photo-sensing Receivers using a-SiC:
based materials - Visible Light
Communication Systems People
(M
2P
)
PhD members (9)
Manuela Vieira (Coordinator)
Alessandro Fantoni
Guilherme Lavareda
João Costa
Manuel Barata
Manuel Vieira
Miguel Fernandes
Paula Louro
Yuriy Vygranenko
• PhD students (5)
• Dora Gonçalves
• João Martins
• Vitor Fialho
• João Mendes
• Vítor Silva
• MSc students (5)
• Ricardo Almeida
• João Reis
• Nuno Mendes
• Hugo Leão
• Fábio Cardoso
03/10/2018
6/1
7 Obje
ctives
Development, optimization and application of
semiconductor based devices: image and color
sensors, optoelectronic devices, solar cells, optical
amplifiers, biosensors, nanostructures and UV and IV
detectors, VLC devices.
Design and modeling of optical devices.
Electrical and numerical simulation of optical devices.
Integration of different technologies, namely optical
sensors, wavelength-division multiplexing, X-ray
detectors and full digital medical imaging.
Optical Communications
03/10/2018 Main
Researc
h A
reas
Applications of semiconductor devices
◦ Wavelength Division Multiplexing (WDM)
◦ Optical biosensors
◦ X-ray flat panel
◦ OLEDs
◦ Nanodevices
Visible Light Communications
◦ Indoor positioning systems
◦ Vehicular Communications
Receivers
Transmitters
V1
V2
Cosmetics
Hall
RedGreenBlueViolet
Transmitters
Facili
ties
Deposition facilities:
◦ Laboratories for support of Semiconductor Thin Film Development using the PECVD
(Plasma Enhanced Chemical Decomposition) techniques.
◦ Laboratories for support of Electronic, Optoelectronic and Microelectronic Device
Processing.
Characterization facilities:
◦ UV-VIS-NIR and IR Spectrophotometers (Shimadzu),
◦ dark/photo conductivity as a function of temperature;
◦ spectral response;
◦ Flying Spot Technique-FST;
◦ Photothermal Deflection Spectroscopy-PDS;
◦ Space Charge Limited Current-SCLC;
◦ C(T)/C(V) measurements,
◦ Coatings uniformity test-bench,
◦ Characterization systems for devices (IV characteristics; annealing test chambers;
degradation tests; interface characterization; Electroluminescence) and Solar simulator
for small areas.
◦ Spectrometers (UV, VIR, NIR, IR) and
◦ Optical Characterization Systems (I-V, C-V),
◦ Electric Characterization Systems,
◦ Material Testing Bench.
Dis
se
min
atio
n
MRS
EUROSENSOR
IBERSENSOR
SENSORCOM
ICANS
Abbreviated Journal Title
APPL PHYS LETT
IEEE T ELECTRON DEV
SENSORS and TRANSDUCERS
J APPL PHYS
J. NANOSCI. NANOTECH J. OPTICAL ENG. J. LUMINISCENCE … .
DoCEIS’
Inte
rna
tio
na
l C
oo
pe
ration
Department of Electrical and Computer Eng., Waterloo,
Canada.
Giga to Nano Electronics Group, Univ. Waterloo, Canada.
University of Cagliari, Italy.
IPE, Stuttgart University, Germany
Institute of Semiconductor Physics, Ukrainian Academy of Science, Kiev, Ucraine.
Institute of Physics, Polish Academy of Sciences, Warszawa, Poland.
Institute of Molecular Physics University, Polish Academy
of Sciences, Poland.
Wurzburg University, Germany.
Polish Academy of Sciences, Poland.
Production of semiconductor devices,
Characterization of materials and devices,
Joint publications.
Manuela Vieira
Manuel A. Vieira
Paula Louro
Pedro Vieira
11
Vehicular communications using V L C:
Future trends and applications
NOBEL in Physics 2009
TWO REVOLUTIONARY OPTICAL TECHNOLOGIES
“The Nobel Prize in Physics 2009 honors three scientists, who have played important roles in shaping the modern information technology, with one half to Charles K. Kao and with Willard S. Boyle and George E. Smith sharing the other half.”
Charles K. Kao Willard S. Boyle
George E. Smith
GL
OB
AL
IN
TE
RN
ET
GR
OW
TH
A
ND
TR
EN
DS
Source: Cisco VNI Global IP Traffic Forecast, 2016-2021
By 2021, 63% of total IP
traffic will be wireless *
CAGR - Compound
annual growth rate
Data traffic
COMMUNICATION SPECTRUM
MHz GHz THz PHz EHz
Radio Microwaves Infrared Visible Ultra violet X rays
3G mobile phone
TV Satellite
2G mobile phone
4G mobile phone
Radar Wi-Fi
100 kHz 1 MHz 10 MHz 100 MHz 1 GHz 10 GHz 100 GHz f (Hz)
Radio frequencies
TV set Shortwave emission
Citizen band
Walkie-talkie FM Radio Radio navigation
10 THz 100 THz 430 THz 750 THz
f/Hz
VLC Visible Light communication
INFRARED VISIBLE ULTRAVIOLET
A B
3 PHz 700 nm 400 nm 30 m 300 m
C Near Short Mid Long Far
700 nm 400
nm
1.4 m 3 µm 8 µm 15 µm 1 mm
OWC Optical Wireless Communications
FSO Free Space Optical Communications
Optical fiber
1550 nm
1310 nm
850 nm
Fiber optics communication
Optical wired communications
MO
TIV
AT
ION
• increased bandwidth
• free and non-regulated spectrum
• line of sight technology (1 – 100 m)
• negligible power
• inexpensive (use of already existing lighting infra-
structures)
VLC – Visible Light Communication
Visible Light Communication Li-Fi is a Visible Light Communications (VLC) system
Wi-
Fi v
s L
i-F
i
Li-Fi and Wi-Fi are quite similar as both transmit data electromagnetically
INT
EG
RA
TIO
N
• The term Li-Fi was coined by Professor Harald Haas in
2011. Haas envisioned light bulbs that could act as
wireless routers.
Li-Fi and Wi-Fi are quite similar as both transmit data electromagnetically.
However, Wi-Fi uses radio waves, while Li-Fi runs on visible light waves.
Li-Fi signals cannot pass through walls, so in order to enjoy full connectivity,
capable LED bulbs will need to be placed throughout the home.
• Data is fed into an LED light bulb (with signal processing technology), it
then sends data (embedded in its beam) at rapid speeds to the photo-
detector (photodiode).
• The tiny changes in the rapid dimming of LED bulbs is then converted by
the 'receiver' into electrical signal.
11011101
10011001
10101001
VL
C S
YS
TE
M
OOK
Indoor scenario of infrastructure-to-device communication.
• room illumination
• position/navigation
• data transmission
AD
VA
NTA
GE
S/
DIS
AV
AN
TA
GE
S
Speed
Latency
Capacity
Th
e In
tern
et
of
Th
ing
s
The integration of IoT devices
and Li-Fi will provide a wealth
of opportunities. For example,
shop owners could transmit
data to multiple customers'
phones quickly, securely and
remotely.
will drive the future networked society
5G is expected to use various technologies such as LTE (Long Term
Evolution), WiFi, Ultra Wide Band (UWB) and VLC to ensure permanent
coverage of the communication network without any interruption of service.
MO
TIV
AT
ION
VLC – Visible Light Communication
Indoors environments
• Light atmospheric absorption
• shadows
• light dispersion
• influence of other light sources
• Internet service distribution
• Navigation techniques
3 Gbps
M. Vieira
M . A. Vieira
P. Louro
A. Fantoni
P. Vieira
25
• FCT – ref. UID/EEA/00066/2013
• IPL/2016/VLC_MIMO/ISEL
• IPL/2017/SMART_VeDa/ISEL.
ACKNOWLEDGEMENTS
Visible Light Communication
Technology for Fine-grained
Indoor Localization
Lisbon
AP
PL
ICA
TIO
N
GPS M
OT
IVA
TIO
N
MO
TIV
AT
ION
VLC: Visible Light Communication
• Dual operation: light + comm
• Infrastructure advantage
• Increased bandwidth
• Free and non-regulated spectrum
• Negligible power
• Inexpensive
• Security
• Harmless to human health
• No EM interference
• Line of sight technology (LoS)
• Distance: 1 – 100 m
• Obstructions
• Atmospheric absorption
• Shadows
• Light dispersion
• Influence of other light
sources
INDOOR USE
OU
TL
INE
RESULTS AND DISCUSSION • Coding/decoding techniques
• Cellular VLC System evaluation
CONCLUSIONS/FUTURE WORK
MOTIVATION • VLC – Transmission of data using light
• Multilayered a-SiC:H heterostructures as optical
filters
SYSTEM DESIGN • The cellular topologies
• The emitters
• The OOK modulation scheme
• The VLC receiver
APPLICATION • Navigation data bits
• I2V Vehicular communication
p-i’-n p-i-n
• Light-to-dark sensitivity
depends on the carbon
concentration
• Color recognition
depends on the applied
bias
400 450 500 550 600 650 700 750 8000,00
0,02
0,04
0,06
0,08
0,10
0,12
0,14
0,16
0,18
0,20
#M007192 (2mWcm-2)
#M007192(L=0)
#M006301(L=0)
#M006291(2mWcm-2)
#M006301(2mWcm-2)
#M006291(L=0)
Sen
siti
vit
y (
A/W
)
Wavelength (nm)-6 -5 -4 -3 -2 -1 0 1 2
-8x10-8
-6x10-8
-4x10-8
-2x10-8
0
a)
S=650 nm
NC#5 (pin/pin)
whithout
optical bias
L=550 nm
L=650 nm
L=450 nm
Photo
curr
ent (A
)
Voltage (V)
a-S
i/S
iC P
ho
tod
iod
es
• Light filtering depends on
the bias wavelength and
side
• WDM device
RGB channels; 6000bps
• Coder/decoder device
IR/RGBV/UV channels;
30kbps
1
0
1
1
1
0
1
1
0
0
0
1
1
0
1
1
1
0
1
1
1
1
0
1
1
0
1
1
1
0
1
1
0
0
0
1
0
0
1
1
1
0
1
1
0
0
0
1
0
1
1
0
VLC receiver
SY
ST
EM
DE
SIG
N
• The system is a self-positioning system in which the measuring
unit is mobile.
• This unit receives the signals from several transmitters in known
locations, and has the capability to compute its location based on
the measured signals.
• p-i'(a-SiC:H)-n/p-i(a-Si:H)-
n heterostructure
produced by PECVD.
Receiver
• Red, Green and Blue
white LED
Transmitter
400 500 600 700 8000.0
0.2
0.4
0.6
0.8
1.0
B
G
R
Inte
nsity (
a.u
.)
Wavelength (nm)
0,0 0,5 1,0 1,5 2,0 2,5
C1,2
payload dataIDSync.[data transmission][10101] [r r r c c c]
V2,3
B2,2
G1,3
R1,2
Cod
ew
ord
(R
GB
V)
Time (ms)
EM
ITT
ER
S
Square Diamond
R1,2 G1,3
B2,2
1
2 3
4
5
6
7
B2,4 V2,3 8
R3,4 G3,3
R1,2 G1,1
V2,1 B2,2
1 2
4
5
6 7
8
9
3
Footprint
regions 1 2 3 4 5 6 7 8 9
Square
topology RGBV RGB RB RBV BV GBV GV RGV RG
Diamond
topology RGV RBV RGBV RGBV RGBV RGBV RGBV GBV -
Unit cell fine-grained lighting topology .
• Four modulated LEDs (RGBV)
located at the corners of a
square grid.
• Four modulated LEDs (RGBV)
located at the corners of a
diamond grid.
Footprint regions
Four-code assignment for the LEDs
CE
LL
UL
AR
TO
PO
LO
GY
Cluster of cells in no-
orthogonal topology
(diamond).
Clusters of cell in an
orthogonal topology
(square).
R1,2 G1,3 R1,4 G1,1
V2,1
V4,3 B4,2 V4,1 B4,4
B2,2 V2,3 B2,4
G3,3 R3,4 R3,2 G3,1
C1,1 C1,2 C1,3
C2,1 C2,2 C2,3
C3,1 C3,2 C3,3
R1,2 G1,3 R1,4 G1,1
V2,1
V4,3 B4,2 V4,1 B4,4
B2,2 V2,3 B2,4
G3,3 R3,4 R3,2 G3,1
C1,1 C1,2 C1,3
C2,1 C2,2 C2,3
C3,1 C3,2 C3,3
R G
V B
R G
V B
Ci,j
Ci,j
• Each node, X i,j, carries its own color, X, (RGBV) as well as its ID position
in the network.
G1,1
V2,2
G3,3
G1,-1
V-2,-2
G-3,-3
R0,1
R0,3 G1,3 R2,3
V0,2 B1,2
R2,1
B3,0
G3,1
B3,2
G-1,1 R-2,1
B-1,2
R0,-1
R0,-3
V0,-2 B-1,-2
Y
X
B1,-2
G-1,-1
G-1,-3 R-2,-3
R-2,-1 G-3,-1
B-3,-2
V0,0 V2,0 V-20 B1,0 B-1,0 B-3,0
R2,-1
Footprint
regions P#1 P#2 P#3 P#4 P#5 P#6 P#7 P#8 P#9
Hexagon
topology
RGV
R’G’V
RBV
R’B’V
G’BV
GB’V
RGB0V
R’G’B’0V
RG0BV
R’ G’0B’V
R0G’BV
R’0GB’V
RGBV
R’G’B’V
RG’BV
R’GB’V
RGB’V
RGB’V
HE
XA
GO
NA
L T
OP
OL
OG
Y
Cluster of cells in 60º
Cartesian coordinates
topology
(hexagon).
Footprint regions 1
1
9
9
XY
FIN
E-G
RA
INE
D
ID: C1,2, #P1
R12 [10101 001 010…]
G13 [10101 001 011…]
B22 [10101 010 010…]
V23 [10101 010 011…]
0,0 0,5 1,0 1,5 2,0 2,5
C1,2
payload dataIDSync.[data transmission][10101] [r r r c c c]
V2,3
B2,2
G1,3
R1,2
Cod
ew
ord
(R
GB
V)
Time (ms)
• The input of the aided
navigation system is
the MUX signal, and
the output is the
system state estimated
at each time step (t).
10011001
11011101
10011001
10101001
010011
010010
001011
001010
0.0 0.5 1.0 1.5 2.0 2.5
payload dataIDSync.
[data transmission][10101] [xxxx yyyy]
V0,0
B1,0
G-1,-1
R0,-1
Co
de
wo
rd (
RG
BV
)
Time (ms)
R0,-1 [10101 0000 1001…]
G-1, -1 [10101 1001 1001…]
B1,02 [10101 0001 0000…]
V0,0 [10101 0000 0000…]
0000 0000
0001 0000
-10011001
00001001 Sign and magnitude representation:
4 BITS
1st BIT : 0 for positive and 1 for negative
Next 3 BITS : magnitude
GL
AS
S
200 nm
(a-SiC:H)
Applied Voltage
Channels
B
TC
O
i
1000 nm
(a-Si:H)
p p n
n
TC
O
Front diode Back diode
G
i’
G
Wavelength
Division
Multiplexing
SY
ST
EM
OP
ER
AT
ION
Op
tica
l
bia
s
V
R
G
B
V
10011001 11011101 10001001
Bit decode LED ID data transmit with fast
blinking
Coder/decoder device
Transmitter / Receiver of VLC
Wavelength
Division
Demultiplexing
• The device acts as an active filter, under irradiation.
• The gain is higher than the unity for wavelengths above 500 nm and lower
for wavelengths below, resulting in an amplification of the green and red
spectral ranges and quenching of the violet/blue ones.
• As the wavelength increases, the signal strongly increases. This
nonlinearity is the main idea for the decoding of the MUX signal at the
receiver.
• 24 ordered levels pondered by their optical gains are detected and
correspond to all the possible combinations of the on/off states.
• Comparing the calibrated levels with the different generation levels
in the same frame of time, a simple algorithm was used to perform
1-to-32 demultiplexer function and to decode the multiplex signals.
DE
CO
DIN
G A
LG
OR
ITH
M
0.0 0.5 1.0 1.5 2.0 2.5
0.2
0.4
0.6
0.8
1.0
1.2
d15d
14
d13d
12
d11d
10
d9d
8
d7d
6
d5d
4
d3d
2
d1
d0
V
B
G
R
0 0 0 00 0 0 10 0 1 00 0 1 10 1 0 00 1 0 1
0 1 1 00 1 1 1
1 0 0 01 0 0 1
1 0 1 01 0 1 1
1 1 0 01 1 0 1
1 1 1 01 1 1 1
R G B V
Norm
aliz
ed M
UX
sig
nal
Time (ms)
0.0 0.5 1.0 1.5 2.0 2.5
0.2
0.4
0.6
0.8
1.0
1.2
IDSync Payload data
P#1
V2,3
B2,2
G1,3
R1,2
C1,2
MU
X (
A)
Time (ms)
• By assigning each output level to a 4-digit binary code (weighted by
the optical gain of the each channel), [XR, XG, XB, XV], with X=1 if the
channel is on and X=0 if it is off, the signal can be decoded.
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5RGBV
[1010]
[1111]
Payload dataIDSync
P#3
P#1
V2,1
B2,2
G1,1
R1,2
C1,1
MU
X (
A)
Time (ms)
R12, G11, B22,V21
R12, G11, B22,V21
CE
LL
UL
AR
VL
C S
YS
TE
M E
VA
LU
AT
ION
• For each transition between an initial location and a final one, two code words are
generated, the initial (i) and the final (f). If the receiver stays under the same region
they should be the same, if it moves away they are different.
• The device’s position (ID position) during the receiving process will be given by
the highest detected level, the level where all the n (n=1, 2, 3, 4) channels are
simultaneously on.
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5RGBV
[0011]
[1111]
[1010]
IDSync Payload data
P#5
P#1
P#3
V2,3
B2,2
G1,3
R1,2
C1,2
MU
X (
A)
Time (ms)
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5
RGBV
[0011]
[1101]
[1111]
IDSync Payload data
P#8
P#5
P#1
V2,3
B2,2
G3,3
R3,2
C2,2
MU
X (
A)
Time (ms)
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5RGBV
[1101]
[0011]
[1111]
IDSync Payload data
P#5
P#8
P#1
V4,3
B4,4
G3,3
R3,4
C3,3
MU
X (
A)
Time (ms)
#P1 (R12G13B22V23) N
AV
IGA
TIO
N D
ATA
BIT
S
• As the receiver moves between generated point regions, the received information
pattern changes. The transition actions are correlated by calculating the ID position
codes in successive instants.
0.0 0.5 1.0 1.5 2.0 2.50.0
0.5
1.0
P#2 (t3)
P#1 (t1)
P#7 (t2)
[1011]
[1101]
[1111]
RGBV
Payload dataIDSyncV0,0
B1,0
G-1,-1
R0,-1
Norm
aliz
ed M
UX
sig
nal
Time (s)
0.0 0.5 1.0 1.5 2.0 2.50.0
0.2
0.3
0.5
0.6
0.8
0.9
1.1
1.2
P#A (t6)
P#3 (t4)
P#6 (t5)
[1110]
[0111]
[1111]
RGBV
Payload dataIDSyncV0,0
B1,0
G1,1
R2,1
No
rma
lize
d M
UX
sig
na
l
Time (s)
12
3
4
6RGBV
t6
X
Y
5
A
t1
1
2
3
4
5
6
8(0,0)
LE
D-B
AS
ED
NA
VIG
AT
ION
SY
ST
EM
Cosmetics
Hall
RedGreenBlueViolet
Transmitters
IND
OO
R L
OC
AL
IZA
TIO
N
Hexagon
Square
CO
NC
LU
SIO
NS
• A a-SiC 1x5 WDM device, with channel separation in the visible range, was presented and its operation as wavelength selector explained.
• Encoding and decoding data was analyzed and the codewords generated using the MUX signals due to the data transmitted together with the check parity bits tested.
• An algorithm to decode the transmitted information was presented. A transmitter capability of 60 kbps using the generated codeword was achieved.
A coupled data transmission and indoor positioning was
presented. To transmit the data, an On-Off Keying code was
used. Two cellular topologies, for the ceiling plans, were used: the
square and the hexagon.
Fine-grained indoor localization was tested. A 2D localization
design, demonstrated by a prototype implementation was
developed.
A detailed analysis of the characteristics of various components
within the VLC system were discussed.
Results showed that is possible not only to determine the
position of a mobile target inside the unit cell but also in the
network and concomitantly to infer the travel direction along the
time.
For future work, by using multiple emitters and receivers, the
transmission data rate through parallelized spatial multiplexing
can be improved.
0.0 0.5 1.0 1.5 2.0
[0101 0011]
V
B
G
R
Code w
ord
(R
GB
V)
Time (ms)
VEHICULAR VLC: ROAD-TO-VEHICLE
AP
PL
ICA
TIO
N
0.0 0.5 1.0 1.5 2.0 2.5
1
2
3
4
5
Position 3
(RB)
Position 1
(RGBV)
Cell 2
Payload dataIDV23
B12
G23
R12
Sync.
MU
X (
A)
Time (ms)
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5
Position 7
(GV)
Position 1
(RGBV)
Payload dataIDSync.V23
B34
G23
R34Cell 3
MU
X (
A)
Time (ms)
• Each decoded message carries the node address of the transmitter
R34 […011 100…]
G23 […010 011…]
B34 […011 100…]
V23 […010 011…]
R12 […001 010…]
G23 […010 011…]
B12 […001 010…]
V23 […010 011…]
R12 […001 010…]
B12 […001 010…]
G23 […010 011…]
V23 […010 011…]
RGBV RGBV
RB
GV
I2V
CO
MM
UN
ICA
TIO
N
10011001
11011101
10011001 10101001
CO
NN
EC
TE
D V
EH
ICL
ES
MO
DE
L
1
2
3
i
n
Street lamp Traffic light
I2V
V2V
V2I
Vehicles
Generic model for
cooperative vehicular
communications
Illustration of the proposed
I2V2V2I communication
scenario:
Connected vehicles
communication in a crossroad.
Until recently…
• (V2V) communication was
limited to brake lights, turn
signals;
• (V2I) was restricted to point
detection (loop detectors).
10011001
11011101
10011001
10101001
10011001
10011001
10101001
10101001
Generated joint footprints
RG
V B
12
4
5
67
8
9
3
Unit cell
•Four modulated LEDs (RGBV) located at
the corners of a square grid.
R1,2G1,1
V2,3V2,1
R1,4
B2,2
G1,3
R3,2G3,1 G3,3
V4,3V4,1 B4,2
G1,5
V2,5
G3,5
V4,5
R5,2G5,1 R5,4G5,3 G5,5
B4,4
B2,4
R3,4
Promising benefits
expected from safety and
mobility improvements at
the road network
LIG
HT
ING
PL
AN
Sync. ID
data
Crossroad
0.0 0.5 1.0 1.5 2.0 2.5
payload dataIDSync.
[data transmission][10101] [r r r: c c c]
V2,3
B2,4
G3,3
R3,4
Codew
ord
(R
GB
V)
Time (ms)
I2V: the street lamp (transmitter) sends a
message to the SiC receiver, located at the
rooftop.
I2V
2V
syste
m d
esig
n
I
V
V
The structure of the frame is a classical one
The message begins with 5 synchronization bits
The rest of the frame consists of 6 ID´s bits,
The payload data bits and a stop bit.
V2V: the information is resent to a leader
vehicle, using the headlights as transmitters
Driving distance
???
Transmitters
receivers Relative
speed???
Co
op
era
tive V
LC
Syste
m E
valu
ati
on
Three different scenarios:
Scenario 1 I 2 V 2 V 2 I
Scenario 2 I 2 V 2 I
Scenario 3 I 2 V 2 V 2 I In order to verify the system operability and
efficiency we have conducted an extensive set
of measurements
Operational procedure:
Each vehicle receives two different
messages:
• I2V and V2V coming from the
streetlight and from the follow
vehicle;
• Compare them and infers the drive
distance and the relative speed.
• Send the information to a next car
(V2V2V) or to an infrastructure
(V2V2I).
Generalized view of the architecture
v=…. t=….
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5
RGBV
[0101]
[1010]
[1111]
I2V
IDSync Payload data
#3
#7
#1
V2,3
B2,2
G3,3
R3,2
MU
X (
A)
Time (ms)
Sce
na
rio
1: I
2V
2V
2I
0.0 0.5 1.0 1.5 2.0 2.50.0
0.5
1.0
1010#P3 (W, t
3)
0101
1111
RGBV
IDSync Payload data
#P7 (W, t1)
#P1 (W, t2)
V2,1
B2,2
G3,1
R3,2
V2V
MU
X (
A)
Time (ms)
Request time: t1
Vehicle 1 sends the
request message to
the infrastructure (V2I)
and informs the signal
controller that this
vehicle desires service
(often called “demand”
for service).
0.0 0.5 1.0 1.5 2.0 2.50.0
0.5
1.0
S
W
B2,2
R3,2
RGBV
[0011]
[1010]
V2I
IDSync Payload data
#3 (W, t1)
#5 (S, t2)
V4,3
B4,4
MU
X (
A)
Time (ms)
Data collected from connected vehicles provides
a much more complete picture of the traffic
states near an intersection
v=…. t=….
Sc
en
ari
o 2
: I
2V
2I
Request time: t2
0.0 0.5 1.0 1.5 2.0 2.50.0
0.5
1.0
S
W
B2,2
R3,2
RGBV
[0011]
[1010]
V2I
IDSync Payload data
#3 (W, t1)
#5 (S, t2)
V4,3
B4,4
MU
X (
A)
Time (ms)
0.0 0.5 1.0 1.5 2.0 2.50
1
2
3
4
5 I2V
[0011]
[1100]
[1111]RGBV
IDSync Payload data
#9
#5
#1
V4,3
B4,4
G3,3
R3,4
MU
X (
A)
Time (ms)
•I2V MUX signal received by a rooftop
receiver moving in the S direction when the
vehicle 2 is located #5
•V2I communication from vehicle 2
to the infrastructure
Vehicle 2 sends the request
message to the infrastructure (V2I) )
and informs the signal controller
that this vehicle desires service.
0.0 0.5 1.0 1.5 2.0 2.50.0
0.5
1.0
1010#P3 (W, t
3)
0101
1111
RGBV
IDSync Payload data
#P7 (W, t1)
#P1 (W, t2)
V2,1
B2,2
G3,1
R3,2
V2V
MU
X (
A)
Time (ms)
v=…. t=….
Scen
ari
o 3
: I
2V
2V
2I
Request time: t3
Pedestrian-only stage (01 phase)
two single-lane road phases
Phasing of traffic flows
Vehicle 3 sends the request
message to the infrastructure
(V2I) and to the leader (V2V)
Vehicle’s intersection access time is defined as
the time at which the head of the vehicle enters
the intersection area
From a capacity point of view is more
efficient, if Vehicle 3 is given access before
Vehicle 2
G13
1
1
2
4 5
6
8
9
8
4
6
2
3
3
4
2 9
1 1
1
7
4 6 6
8 8
8
5
7
2
2
6 4
7
R14
3
3
1
B22 V21 V23 V23 B24
7
5 5 5
9
V43 B44
G33 R32 G31 R34 9
G35
7
6 4
1
3
3
2 8 R54 9
4 6
7
2 8
G53
9
Vir
tual ro
ad
netw
ork
:
I2V
2V
2I
Information flow towards the traffic light:
Improvement of control by precise information
about traffic Traffic Light
Phase Assistant”
NETWORK
Light-activated pi’n/pin a-SiC:H devices combines the
demultiplexing operation with the simultaneous
photodetection and self amplification.
Connected vehicles information from the network (I2V),
vehicular interaction (V2V) and infrastructure (V2I) is
analyzed.
A generic model of cooperative transmissions for
vehicular communications services is established.
Co
nclu
sio
ns
The experimental results,
confirmed that the proposed
cooperative VLC architecture is
appropriate for the control and
management of a traffic light
controlled crossroad network.
Two-level optimization:
phase sequence and duration.
1
2
3
i
n
Street lamp Traffic light
I2V
V2V
V2I
Vehicles
Transmitters V1
V2
001 010 011
Receivers
001 010 011
001 010 011
I2V
V2VV2I
V3
TEAM
Manuela Vieira Alessandro Fantoni Paula Louro Miguel Fernandes Yuri Vygranenko João Costa Manuel Barata Manuel A. Vieira António Maçarico João Martins Vitor Fialho Donatello Brida Victor Silva Reinhard Schwarz Manfred Niehus
A group of experienced and young researchers covering the areas of materials and devices processing; materials and devices characterization and optimization, well supported by the physics modelling of the devices and the corresponding software for information extraction
Thanks for your attention