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