Visible Light Communication in Intelligent Transportation Systemsicc2014.ieee-icc.org/2014/private/Tutorial14.pdf · · 2014-05-30Visible Light Communication in Intelligent Transportation

Visible Light Communication in Intelligent Transportation

Systems Navin Kumar, PhD

Sr. Member IEEE, IAENG(HK), IETE, IE(India)

Amrita University, Bangalore

[email protected]

Monday, May 12, 2014

http://icc2014.ieee-icc.org/2014/private/programTutorials.html

Amrita Vishwa Vidyapeetham Bengaluru Campus




Outline

2 Monday, May 12, 2014 Navin

Introduction Intelligent Transportation Systems

Advantages/Applications

Intelligent vehicles and Infrastructure

Vehicular Communication

Overall System Architecture Advantages and Applications

Visible Light Communications

ITS Strategic Plan and Opportunities

Technical Details and Prototype Experiments and Results Research Opportunities Conclusions

Introduction: WHAT IS ITS?

Intelligent transportation system (ITS) refers to efforts to add information and communications technology to transport infrastructure and vehicles, in order to:

– improve safety

– reduce vehicle wear,

– reduce transportation times, and

– reduce fuel consumption.


DEFINITION …

ITS improves transportation safety and mobility and enhances productivity through the use of advanced communications technologies.

ITS apply well-established technologies of communications, control, electronics and computer hardware & software to the surface transportation system.


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Identified Benefits

Time Savings

Improved Throughput

Reduced Crashes and Fatalities

Cost effectiveness

Increased Customer Satisfaction

Energy and Environmental Benefits






Problems Caused by Congestion and Options

Problems:

Increased…

– Travel time

– Travel cost

– Air pollution

– Accident risk Options: Construct new roads

Covered in geometric design Not likely to happen on a large scale

Reduce Traffic Travel demand management Alternative transportation

Increase existing infrastructure capacity Uses intelligent transportation systems (ITS) Monday, May 12, 2014 7

Construction is Part

of the Solution

But will be VERY expensive and politically painful. Because where it is needed most is in the heart of metropolitan areas. Monday, May 12, 2014 8

Option 2: Alternative Transport

New rail capacity or aother medium which would avoid the congested highways, will be just as difficult and expensive to build as new highways.

New Rail Capacity.

SkyTran: Personal

MagLev Transporter


Option 3: Increase Existing Infrastructure Capacity

An alternative to expensive new highway construction is the implementation of strategies that promote more efficient utilization of transportation infrastructures.

These strategies are known as the Intelligent Transportation Systems (ITS).


This aims to: reduce travel time, ease delay and congestion, improve safety, and reduce pollutant emissions

Intelligent transportation systems

ITS, encompass a broad range of wireless and wireline communications-based:

– information,

– control and

– electronics technologies.

When integrated into the transportation system infrastructure, and in vehicles themselves, these technologies help:


monitor and manage traffic flow, reduce congestion, provide alternate routes to travelers, enhance productivity, and save lives, saves time and money.

Applications Overview Global Positioning Systems Weather information systems Bus Information System Traffic and transit management Real-time information Parking Incident management Emergency management Electronic toll collection Commercial vehicle operations

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Five Primary Functional Areas of ITS

Advanced Traffic Management Systems (ATMS)

Advanced Traveler Information Systems (ATIS)

Commercial Vehicle Operations (CVO)

Advanced Public Transportation Systems (APTS)

Advanced Vehicle Control Systems (AVCS)






Application: Bus Information System

• Public Transport Information

– Countdown: Real-time Bus Stop Information


Application: Real-Time Information

Automobile traffic

Public transport

Parking

Airport arrivals/departures

News, banking, stocks…

Information on -availability Guidance to: - Available facility - Actual spot

Incident Management

Commodity Classification Automated Tracking System (CCATS)

Camera and Computer-Aided Incident Detection (CCIDS)

CCATS & CCIDS: Video-Based Solutions for Data Collection and Incident Detection

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Application: Incident Management


Road Safety and ITS Road Crashes[WHO’08]:

– the second leading cause of death among young people aged 5 to 29

– the third leading cause of death among people aged 30 to 44 years

– Over 1.2 million people are killed annually

Traffic Congestion: – affects the day-to-day life of citizens

– has a great impact on business and economic activities

These issues therefore generate less income, affecting the sustainable growth of cities throughout the world

ITS have drawn a lot of attention to solve various traffic problems

The area of ITS is directly related to human and material safety


Application scenario: IntelligentVehicles & Infrastructure

Driver Assistance Systems

Collision Avoidance Systems

Collision Notification Systems

Electronic payment and pricing

Emergency management

Transit Management

Freeway Management

18 Navin Kumar Monday, May 12, 2014

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Application scenario: Intelligent Infrastructure

Road Weather Management

Roadway Operation and Maintenance

Information Management Traveler

information Crash Prevention

and Safety

Commercial Vehicle operation


Intelligent Transportation System


ITS & Vehicular Communication (VC) Technology

Inside car – Bluetooth, Zigbee

Car to car – VANET,802.11p (5.85-5.925 GHz)

Car to road – 802.11p

Car to Internet – 3G, WiMAX

(current) CALM (Continuous Air-interface, Long and Medium range )


VC Service Scenario

Sensor

Access Point

Car to Car

Car to Road

Home Network

Roadside Assistance

Service Provider

Sensor

IMS

InternetRadioAccess

Network

WLAN, WiMAX,

GSM, GPRS,3G & B3G

Sensor

Sensor

PoC

PresenceeCall

IPTV

Context–AwareService

Provisioning


VC Service Integration

WLAN

WiMAX

UMTS

GPRS

GSM

IMSCore

Network

Home Network

Radio

Access

Network

PoCPresence

eCall IPTV

Context–AwareService

Provisioning

Internet


Advanced Traffic Management Systems

Photo from the Human-Computer Interaction Lab: University of Maryland Monday, May 12, 2014 24 Monday, May 12, 2014

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WSDOT Traffic Systems Management Center


Advanced Traveler Information Systems


Advanced Public Transportation Systems


Advanced Vehicle Control Systems

Intelligent

Cruise Control (ICC)

System


ITS Strategic Plan – Research Questions & Framework

Ap

plic

atio

ns

Tech

no

logy

P

olic

y

ALL MUST BE ANSWERED TO BE DEPLOYABLE

77%

18%

5% What policies/governance/funding are required for sustainability? How to address public concerns for privacy and ensure that applications do not cause driver distraction?

Is technology stable, reliable, secure, and interoperable?

Are international standards available to ensure interoperability?

Are applications available and benefits validated? What is the minimum infrastructure needed for the greatest

benefit? How much, where, when and what type?

What is the degree of market penetration required for effectiveness?


Our Task In our town or city – what are our

transport objectives – what do we want our transport system to achieve and how do we want it to improve?

From what we’ve seen so far – how could ITS help us to achieve our objectives? … and now on to how Visible Light Communication (VLC) as one of the technologies can be used in ITS…


What is VLC?


31 http://icc2014.ieee-icc.org/2014/private/programTutorials.html




Introduction

Visible Light Communication ?

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0 1 0

1

0 1 0

1

0 1

1 0

1

0

1 0 0 1

1 0

1

0 1

0

0 1

1 1

0

0 1

Tx

Rx

Communication using visible light Wirelessly.

Light Emitting Source (one component)

Light Detector (one component)

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Introduction: History

• Smoke signals of the ancient tribes

• The use of fire or lamp Beacon fire, lighthouse, ship-to-ship comm.

33 5/12/2014

Information delivery using mirror reflection (Heliograph): is a wireless solar telegraph that signals using Morse code flashes of sunlight reflected by a mirror.

Traffic Signal

Traffic light : R/G/B color multiplexing (Walk/Stop)

http://en.wikipedia.org/wiki/File:Turkish_heliograph_at_Huj2.jpg

http://www.trafficlights.com/T5ad.htm

Introduction: History …

34

Alexander Grahm Bell’s Photophone (1880) Optical source: sunlight Modulation: vibrating mirror Receiver: parabolic mirror Distance: 700 ft (213m)

Source: http://www.freespaceoptic.com/

In 1920, somewhat by accident, Losev foresaw the usage of optical links to relay information.

In 1969, Gfeller presented “Wireless In-House Data Communication via Diffuse Infrared Radiation”. It became the stepping stone to VLC.


Facts, Figures, and Trends of Wireless Networks and Technology

35

Several Technologies move in the same direction

4G Many Access

Networks

5G


Introduction

36






Introduction • Wireless data transmission via optical carriers:

opportunity, many yet unexplored.

37

Optical Wireless Communication (OWC): Significant technical and operational advantages.

OWC, in some applications: a powerful alternative to radio frequency (RF) and,

complementary to existing RF wireless systems.


Frequency Spectrum

38

1024 1022 1020 1018 1016 1014 1012 1010 108 106 104 102 100 ν(Hz)

λ(m)10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2 100 102 104 106 108

Increasing Frequency(ν)

Increasing Wavelength(λ)

380nm 780nm

γ rays X rays UVMicrowaveIR FM AM

Radiowave

Longwave

Visible Spectrum

Licensing Area/ISMSpecial purposed Area

Non-Licensing Area

1024 1022 1020 1018 1016 1014 1012 1010 108 106 104 102 100 ν(Hz)

λ(m)10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2 100 102 104 106 108



380nm 780nm


Radiowave

Longwave

Visible Spectrum


Non-Licensing Area

Low Frequency (High wavelength)

Large Coverage Mobility

High Frequency (Small wavelength)

High Bandwidth Security

IrDA : 334THz(900nm) to 353THz (850nm) Monday, May 12, 2014

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Introduction … • Variations of OWC can be employed in a

diverse range of communication applications:

39

outdoor inter-building links (on the order of kilometres)

very short-range (on the order of millimetres) optical interconnects within integrated circuits


Optical Wireless Communication and Systems

40

• Usually, OWC includes:

J. M. Kahn, and. J. R. Barry, "Wireless infrared communications," Proc. of the IEEE, pp. 265-298, 1997.

1. Infrared (IR): for short range [Kahn & Barry,

1997], - approximately 1 to 400THz frequency band,

(Much of the energy from the Sun arrives on Earth in the form of infrared radiation).


OWC – Infrared …

Used for -night vision equipment when there is insufficient visible light to see.

• Infrared imaging (capturing invisible infrared images and making them visible)

• as heating source

• IR data transmission in short-range communication

• These devices usually conform to standards published by IrDA, (Infrared Data Association).

• Remote controls, etc.

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http://en.wikipedia.org/wiki/Infrared_Data_Association




OWC – Free Space Optics

42

- A technology that can be installed license-free worldwide, - can be installed in less than a day. -Offers optical fiber like bandwidth and data speed - Normally so called, Wide band Home Access or --Last Mile Access Network

This line-of-sight technology approach uses invisible beams (193.5GHz and 382.2GHz: 1550 nm, 785 nm) of light to provide optical bandwidth connections.

2. Free-Space Optics communication: for longer range


FSO: Applications

43

Fig.: A Simple Point-to-point FSO Connection

Fig.: FSO Corporate Networks


FSO: Applications

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FSO: System Requirement and Design Issues

Tracking

• The requirements for tracking systems in carrier-class free-space optics systems.

45

Scintillation and atmospheric effects Scintillation effects and techniques for mitigating the detrimental effects of scintillation.

Power Control and Eyesafety The benefits of power control for long-term laser reliability and eyesafety


FSO: System Requirement and Design Issues

46

Fig.: Atmospheric Issues


FSO: System Requirement and Design Issues ….

• Ex.: Attenuation because of Fog/Snow storm

47

Taken from - Scott Bloom, The Physics of Free-space optics, white paper AirFiber Inc.


FSO: Overall Functional Blocks

48

Transmitter Laser, Lens, Driver

Receiver

Photo Detector Front End Amplifier

Tracking

Microprocessor based tracking/alignment system

Fig.: Overall FSO Block Diagram


BASIC COMPONENTS: OPTICAL WIRELESS

Transmitter

•

49

Optics

Array of sources can also be used

Source

LED or Laser diode -Eye safety regulation means that high power required sources to be modified -Three ranges:

# Visible (used for both illumination and data transmission) # Near infrared

700nm>Wavelength<1400nm- Low cost Wavelength>1400nm- Eye safe


OWC – Basic Components …

Receiver consists of:

50

Photo Detector

- Optical power to photo current

Input radiation

Photodetector (or array of detectors)

Optical filter

Supported by: Optical filter

Rejects ‘out-of-band’ ambient illumination noise

Concentrator

AMP

Amplifier and following processing

Concentrator or Lens Collection of radiation

Preamplifier (or number of preamplifiers) normally Transimpedance Amp. and signal processing


OWC Configuration

51

Lin

e-o

f-si

ght

(Lo

S)

Non LoS

BASIC CONFIGURATION: LoS or DIFFUSE


Configuration Characteristics

52

Diffuse -Multipaths from Transmitter to Receiver Robust to blocking

o Large coverage

- Path loss More - Subject to multipath dispersion

LoS - Single path from Transmitter to Receiver

No dispersion Path loss Less

o Very high bandwidth available

Difficult to provide coverage


OWC Characteristics

53

MERITS - Very High Bandwidth

o 200THz carrier frequency

-Secure (LoS) -Cost Effective -Interference

o Suitable for RF sensitive

environments

-Potential for low power

Problems and possible Solutions - Noise from ambient light

o Optical filtering o Electrical filtering in receiver

- Less sensitive than radio - Link Blocking

o Geometrical solutions o Diffuse channels o Combine with RF

- Available components optimised for fibre-optic applications

o Higher performance available if optimised for OW


Development

54

Optimal Integration into 4G Infrastructures

Emerging Area Visible Light Communication






VLC… VLC is a novel kind of Optical Wireless which uses

license-free visible light spectrum (380nm-780nm) to carry information wirelessly.

Monday, May 12, 2014 55

1024 1022 1020 1018 1016 1014 1012 1010 108 106 104 102 100 ν(Hz)

λ(m)10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2 100 102 104 106 108



380nm 780nm


Radiowave

Longwave

Visible Spectrum


Non-Licensing Area

1024 1022 1020 1018 1016 1014 1012 1010 108 106 104 102 100 ν(Hz)

λ(m)10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2 100 102 104 106 108



380nm 780nm


Radiowave

Longwave

Visible Spectrum


Non-Licensing Area

VLC …

Monday, May 12, 2014 56

The emitter is normally LED source which has inherent characteristics of high speed switching and therefore, technology performs DUAL FUNCTIONs of Lighting and Data Communication simultaneously.

It is a cost effective technology, no interference to RF and widely suitable as supplementary technique to the most popular RF systems.

VLC offers short/medium range data communication


VLC: Advantages VLC System has many advantages especially derived from advancement in

light emitting diodes (LEDs) technology.

– Cost effective (can be designed on existing infrastructure)

– Energy efficient system (LED usage can save over 60% energy)

– Long life (LEDs technology usage)

– Unlicensed and unregulated spectrum (free in life is the best)

– Theoretically Unlimited bandwidth (limited to electronics devices)

– Harmless to human (unlike Infrared)

– Uses at restricted places (unlike RF-EMI) such as Hospital, aeroplane

– Parallel and Directive communication ( use of colour and directive LEDs)

– Highly Secure (LOS – what you see is what transmit)

– Considered a Green Technology (less CO2 emission – use of LEDs)

– Ubiquitous characteristics (where light can reach, data comm is possible)

– and many more……….

57 Monday, May 12, 2014

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58

Visible Light Communication (VLC)

That is, Communications of information using light (visible to the human eyes).

VLC offers short/medium range data communication

Visible Light Communication is a Novel kind of Optical Wireless Communication which uses visible light (400THz to 790THz) from Light Emitting Diodes (LEDs) as a medium for data communication.


5/12/2014 59

VLC Motivation

Intrinsic Characteristic of VLC •Visibility •No interference /No regulation

Environmental trend •Energy saving •Green Technology

Communication Community trend •Ubiquitous (Connected anywhere, anytime) •Security

LED Advancement •LED technical evolution (efficiency, brightness) •LED illumination infrastructure

Advancement in LEDs Technology.

60

VLC Motivation …

LEDs as brighter as our conventional lights (Fluorescent or Incadescent lamp)

-Switching speed.

-Illumination characterisitics

Mostly in terms of:

Inherent characteristic (Semiconductor Device).

&


61

VLC Motivation – LED Illumination

0

20

40

60

80

100

120

140

160

180

200

2 7 1020

3040

47

115

136

186

200lm/WLuminous Efficacy






62

VLC Motivation –LED Advancement


Therefore, Visible Light emitted from LED can be modulated to send information data i.e. Simultaneous operation of Lighting and Switching.

63

VLC Motivation…

Free Spectrum (Best things in life are free )

At the same time, LEDs can switch at high rate (over 10 MHz) [as such they are Semiconductor devices]


64

VLC Motivation – LED Applications

Illumination moving from incandescent/ fluorescent to solid state sources (LEDs) - Predicted to become predominant method for room illumination - Used extensively in traffic systems (traffic signals, rear light cluster) - Headlight is being also used - Extra wireless capacity available at (potentially) low cost


5/12/2014 65

LED- The VLC Source

Single chip LED spectrum

Red Green Blue -Higher cost -Higher bandwidth -For WDM -Modulation without colour shift

Blue LED & Phosphor -Low cost -Phosphor limits bandwidth -Modulation can cause colour shift

General Characteristics:

Ubiquitous: Omni-presence.

Harmless for human body and electronic devices.

Available visible light bandwidth is about 300THz. It is considerably larger than the current available radio frequency bandwidth (about 300GHz)

Achievable at Low Cost and on Existing Infrastructure or with slight modification

66

VLC Characteristics


Ambient interference:

Obstacles: Must obtain a Line-of-Sight (LoS).

Interferences from other visible light sources (sun, bulbs…)

Also suffer from the multi-path effect as light reflects.

67

VLC Characteristics


5/12/2014 68

VLC Characteristics: Relative Advantages and Disadvantages with Radio and Infrared (IR)

Communication

Parameters Radio Infrared VLC

Bandwidth Around 300GHz Few 100 THz 300 THz

Data Rate Few 100 Mbps Few 10 Mbps Dependent on distance and limited by LED switching speed

Spectrum Regulation Licensed Regulated & Licensed Not licensed

Safety Issue Susceptible to the biological damages to humans by the electromagnetic wave.

Eye safety problem No danger to eyes or biological effect. Easily used with medical instruments or even on airplane.

Usage Everywhere with cell phones and the wireless LAN, etc

Notebook, Cell Phone, PC etc.

Getting popularity

Suitability Wide applications and popularity. Restricted in Hospital and airplane

Short range (mostly indoor) Short & Medium, both indoor and outdoor

Implementation and cost Complex, Costly Easier, cost effective Cost effective, Used on existing infrastructure or with slight modification

Security Many complex algorithm needed May be secured (very short distance)

Secured (What you see is what you transmit)

Complex and Challenging

VLC Can be a supplementary and not replacement to Radio

69

RF or Optical Link?

OW OW


70

VLC Applications






INDOOR

VLC Applications …

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VLC Applications: Indoor

LiFi Configuration

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VLC Applications: Indoor …

Music Broadcast Parallel Transmission (Taken

from Nakagawa Lab, Japan)

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VLC Applications: Outdoor UNDERWATER

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VLC Applications: Outdoor …

75 Monday, May 12, 2014

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INTELLIGENT TRANSPORTATION SYSTEMS (ITS)

VLC Applications: Outdoor …

5m

7m

3m

30mLED Lights

A scenario of VLC in ITS Ubiquitous Communication with Road Illumination


The project VIDAS (VIsible light communication for advanced Driver Assistance Systems) discusses one of the use cases of the emerging technology, VLC and the THESIS is in the framework of the project. 76

VLC Applications: Outdoor - ITS

What’s behind the bend?

Integration of VLC with ITS

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VLC Applications: ITS-Road Safety

VLC as Advanced Driver Assistance System: pls clk to

see

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Overall Architecture

VLC System

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Block Diagram: Conceptual Design

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Emitter Characteristics and Model:

LED (Lambertian Model):

81

VLC Modelling

where θ is the viewing angle and E0(d) is the irradiance (W/m^2), also given in luminous flux (lm) on the axis at a distance d from the LED.

Fig.: Lambertian Emitter Source

(1)


82

Field Programmable Gate Array & Hardware Implementation

PN Code

Sequence Corr. Pk

Partial Corr. Pk

Observations

Novel Designed

+1+1+1-1-1 -1+1-1-1+1

±10

±2

-DC Balanced -Low resources -Easy Implementation -PG = 10dB

Barker +1+1+1-1-1-1+1-1-1+1-1

±11

±1

-Nearly DC Bal. -High Resource -Complex -PG = 10.4dB

PN Code

Input Data

MicroBlaze

DPLB

IPLBILMB

DLMB INTR

BRAM

INTC UART

LMB

LMB

PLBClock

IRQ Lines

50 MHzMB

PLBLMB

SIK

DataBuffer

+Frame

Processing

Binary

DSSS EMITTER CORE

AWGN(channel SNR

simulation)

Bipolar to

Unipolar

Output to Optoelectronics

GPIO

Frame

Processing

ClockManager

Unipolar to Bipolar

ADC

GPIO

Output Data

MicroBlaze

DPLB

IPLB ILMB

DLMBINTR

BRAM

INTCUART

LMB

LMB

PLB Clock

IRQ Lines

50 MHzMBPLBLMB

DSSS RECEIVER CORE

Input from Optoelectronics

SYNC

Matched Filter

PN Code

Treshold Detector

PER Bipolar to Unipolar

EMITTER ARCHITECTURE RECEIVER ARCHITECTURE


Conceptual Design ....

Layer Architecture and ITS Integration ..

83

Under Review –(1) Navin K., Luis A. Nero and Rui L. Aguiar, “VLC Layer Architecture for ITS”, IEEE ITS Magazine

(2) Navin K., Luis A. Nero and Rui L. Aguiar,” Employing Traffic Lights as Road Side Unit for Road Safety Information Broadcast”, Book Chapter


Emitter Model and Design

84

Optimized Placement Multilane Traffic Light System set-up

(1) Navin Kumar, Luis Nero Alves and Rui L. Aguiar, “Design and Analysis of the Basic Parameters for Traffic Information

Transmission using VLC”, Proc. IEEE Intl. Conf., Wireless Vitae’09, May 17-20, 2009 .

(2) Navin K., Nuno R., Luis A Nero and Rui L. Aguiar, “Analysis and Design of LED-based Traffic Light Emitter Model for Road Safety Application”, Elsevier Journal Transportation Research Part C. – Under Review

200mm dia TL, 240 LEDs, 1200mcd


Modulation Analysis

85

OOK Multilevel PPM Inverted PPM Sub Carrier PPM DSSS SIK - Interference cancellation - Avoid Jamming - Tolerance of Noise - Very High Data Rate is not important

DSSS SIK Operation

(1) Navin K., Luis A. Nero and Rui L. Aguiar, “Performance Study of Direct Sequence Spread Spectrum based VLC Systems for Traffic Information Transmission,” – Under reivew (IEEE Transaction on VTS)


FPGA & Hardware Implementation

86

PN Code

Input Data

MicroBlaze

DPLB

IPLBILMB

DLMB INTR

BRAM

INTC UART

LMB

LMB

PLBClock

IRQ Lines

50 MHzMB

PLBLMB

SIK

DataBuffer

+Frame

Processing

Binary

DSSS EMITTER CORE

AWGN(channel SNR

simulation)

Bipolar to

Unipolar

Output to Optoelectronics

GPIO

Frame

Processing

ClockManager

Unipolar to Bipolar

ADC

GPIO

Output Data

MicroBlaze

DPLB

IPLB ILMB

DLMBINTR

BRAM

INTCUART

LMB

LMB

PLB Clock

IRQ Lines

50 MHzMBPLBLMB

DSSS RECEIVER CORE

Input from Optoelectronics

SYNC

Matched Filter

PN Code

Treshold Detector

PER Bipolar to Unipolar

PN Code

Sequence Corr. Pk

Partial Corr. Pk

Observations

Novel Designed

+1+1+1-1-1 -1+1-1-1+1

±10

±2

-DC Balanced -Low resources -Easy Implementation -PG = 10dB

Barker +1+1+1-1-1-1+1-1-1+1-1

±11

±1

-Nearly DC Bal. -High Resource -Complex -PG = 10.4dB

EMITTER ARCHITECTURE RECEIVER ARCHITECTURE


VLC Prototype

87

VLC Receiver

OPTOELECTRONICS & FPGA

Receiver

FPGA Rx

FPGA Tx

OPTOELECTRONICS AND FPGA DEVELOPMENT


VLC Prototype Experiment in Lab

88

(1) Domingos Terra, Navin Kumar, Nuno Lourenço, Luis Nero Alves, and Rui L. Aguiar,” Design, Development and Performance Analysis of DSSS-based Transceiver for VLC”, IEEE EUROCON, Lisbon, Apr. 2011


Experiment Scenario (Lab Environment)

89

Distance Tx –Rx (2.5m) Height (0.85m) -Lights ON -Lights OFF


Experiment Scenario Outdoor/Daylight

90

Bright Sky, Directly Under Sun at Noon time – Detector facing the Sun


Experiment Scenario Pavilion of (60 x 40m)

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Experiment Scenario Outdoor/Night

92


Result Received Average Power

93

0.0E+0

2.0E-6

4.0E-6

6.0E-6

8.0E-6

1.0E-5

1.2E-5

1.4E-5

1.6E-5

1.8E-5

2.0E-5

0 10 20 30 40 50 60 70

Re

ceiv

ed

Po

we

r (W

/cm

2)

Distance (m)

Received Average Power over Distance

Axial Distance Received Power

Received Power at 3.5m Offset from Axis


Result Received Messages

94

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10

Me

ssag

e H

it [

%]

Signal-to-Noise ratio [dB]

25 Chars

50 Chars

100 Chars

256 Chars

Message Length:

(1) Navin Kumar, Domingos Terra; Nuno Lourenço; Luis Nero Alves, and Rui L. Aguiar,” Visible Light Communication for Intelligent Transportation in Road Safety Application”, IEEE IWCMC 2011, Vehicular Communications Symposium, Istanbul, Jul 2011.


Result Received Messages ....

95

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30 40 50 60

Me

ssag

e R

ece

ive

d (

%)

Distance (m)

Close Pavilion (Dark Environment)

Bright Sun Light (Noon Hour -Detector Directly Facing Sun Direction) Evening (Sun set) with Street/Road light ON

Street Light point

Street Light Point

0

20

40

60

80

100

0 5 10 15 20 25 30 35 40

Me

ssag

e H

it [

%]

Distance [m]

Outdoor Night

Outdoor Night - Height Offset Outdoor DayLight

Environment Test (25

(2,5m)


Result Synchronization Loss

96

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

0 10 20 30 40 50

Syn

chro

niz

atio

n L

oss

es

Distance (m)

Environment Test:

Outdoor Night

Outdoor Bright Sun Light

Controlled Dark: Height Offset (1,65m)






Result Packet Error Rate

97

1,0E-7

1,0E-6

1,0E-5

1,0E-4

1,0E-3

1,0E-2

1,0E-1

1,0E0

0 10 20 30 40 50

Pac

ket

Erro

r R

ate

Distance (m)

Environment Test:

Control: Dark (Height Offset 1,65m)

Outdoor Bright Sun Light

Outdoor: Night


Result Packet Error Rate ....

98 Monday, May 12, 2014

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A £5M Research Programme on Visible Light Communications… – ‘Ultra-parallel visible light communications (UP-VLC)’,

– Collaboration between leading research groups at the Universities of Strathclyde, Edinburgh, St Andrews, Oxford and Cambridge.

– Its basis is the >1Gb/s modulation capability recently shown for individual micro-sized gallium nitride LEDs

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Current Status …

http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/K00042X/1 .

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http://visiblelightcomm.com/a-5m-research-programme-on-visible-light-communications/

http://visiblelightcomm.com/a-5m-research-programme-on-visible-light-communications/

http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/K00042X/1

Noise Sources

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Challenges & Opportunities


–Minimizing the effect of external noise (artificial or natural)

–Ambient lights effect

– Interference minimization

Uplink design

Long range communication (LoS link required), and many more ....

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Challenges & opportunities ..


High data rate (limitation of LED/photo diode switching)

–Different modulation including Optical MIMO

–Adaptive Modulation technique for different applications

–Using Equalization

Front end with gain control

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Challenges & Opportunities ..


V-LAN

–V-LAN on aeroplane

–Ubiquitous high data rate communication

Integration with Infrastructure

–RF/VLC Integration

–UP Link / Retrofitting

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Challenges & Opportunities …


Though very interesting, but many challenges:

– Uplink design

– Minimizing the effect of external noise (artificial or natural)

– Ambient lights effect

– Front end receiver design with enough dynamic range

– Interference minimization

– High data rate (limitation of LED/photo diode switching)

– Long range communication (LoS link required), and many more ....

Challenges and Research

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Research: (VLC is at very early (infant) stage)

– Different modulation including Optical MIMO

– Adaptive Modulation technique for different applications

– Front end with gain control

– V-LAN

– V-LAN in aeroplane

– Long distance communication

– Underwater communication

– Ubiquitous high data rate communication

Challenges and Research …..

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Conclusions

• VLC is a cost effective system with many advantages especially leveraged from advancement in LEDs.

• VLC has prospective applications (still remains unexplored) both indoor and outdoor.

• Use of VLC in ITS as road safety system is a novel idea and directly related to human and material safety.

• Tremendous scope of research available in both VLC as well as ITS.

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Thank You !

[email protected]



Amrita Vishwa Vidyapeetham Bengaluru Campus




Visible Light Communication in Intelligent Transportation Systemsicc2014.ieee-icc.org/2014/private/Tutorial14.pdf · · 2014-05-30Visible Light Communication in Intelligent Transportation

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