Abstract—In this paper, we present
initial designs and results of a small-scale prototype of a vehicle to vehicle
communication system using light fidelity (Li-Fi) technology. By modulating the
vehicle’s tail lights, it is possible to transmit event-based messages with the
current status of the car. Vehicle to vehicle communication is the most
effective solution that has been used in order to reduce vehicles accidents.
Several case studies mimicking the vehicle
to vehicle communication via LI-FI are explored in this work.
Keywords—V2V, LI-FI, LED’s, VANET, MANET, WI-FI, GPS,
Li-Fi is an important and popular technology in the communication
system. Li Fi is nothing but the Light fidelity communication systems. It is
the very fast and inexpensive wireless communication systems and is the optical
version of the Wi-Fi. The technology works by adapting light emitting diode
(LED’s) to send digital type of information, invisible to the naked eye. The
usage of light emitting diode (LED) eliminates the need of complex wireless
networks and protocols.1
In this, we present initial designs and results of a small-scale
prototype of a vehicle to vehicle communication system using light fidelity
(Li-Fi) technology. Vehicle to vehicle communication is the most effective
solution that has been used inorder to reduce vehicles accidents. The proposed
use of Li-Fi technology comprises mainly light-emitting diode (LED) bulbs as
means of connection of sending data through LED spectrum as an optical wireless
medium for signal propagation.
1) 5.9 GHz DSRC Wireless
Dictated short range (1000 meters) communication (DSRC) for Intelligent
Transportation Systems (ITS) has opened the door to hundreds of projects and
applications of vehicle to vehicle communication around the world. In 1999 the
federal communication commission reserved licensed bandwidth of 75 MHz
spectrum around 5.9 GHz that allows
information to be exchanged among vehicles regardless of their brand.
This spectrum will provide very high data rates with low latency and high
security in matter of supporting this wireless communication between vehicles,
set of standards were needed to ensure that vehicles understand each other, for
example, IEEE 802.11p-2010 standard of wireless link for V2V communications and
IEEE P1609.x/D5.8 protocols for information exchange across the wireless link.3
2) Wireless Ad Hoc Networks
Vehicular Ad-hoc network (VANET) technology was introduced in 2000 as a
specified application of mobile ad hoc networks (MANETs). This network uses
vehicles in the road as a router or node in order to communicate at a distance
of 100-300 m using several protocols. The networks basically rely on Wi-Fi,
WI-Max and DSRC technologies in addition to 3G networks.4
3) Without Wi-Fi or GPS
Husain Fidvi have proposed vehicle to vehicle communication system that
does not require a tracking global positioning System or even a Wi-Fi or 3G
wireless connectivity. It was proposed to use Programmable Interface Controller
(PIC) sonar which sends 40 KHz short pulse of sound that is undetectable by
human ear. The echo of the signal will be detected by microcontroller. The distance
is calculated by the time required for echo signal to be transmitted and
received. This technology is demonstrated in the figure below.5
Several concepts of Li-Fi had been introduced along with existing
techniques and classical trends used for vehicle to vehicle communications.
Using visible light for communication does not influence in the radio-frequency
frequencies from the electromagnetic spectrum used for other common communication
In this work, we aim to develop a cost effective yet inexpensive
mechanism for vehicle to vehicle communication using an optical wireless
communication medium, which is light.
III. LI-FI & V2V COMMUNICATION.
the last decade Light Emitting Diodes (LEDs) have become a familiar technology
for a variety of lighting applications, including automotive. It’s easy to verify
their superior efficiency (measured by lumens/watt) and quality
by color stability and lifetime) compared to the incandescent or halogen lamps
commonly used in the past, and as the price of LED devices has fallen it’s hardly
a surprise that LEDs are emerging as the dominant lighting technology.
manufacturers have been adopting LED lights on their premium models for more
than 10 years. As the technology has matured, LED lights mounted on mid-range
models are now also commonplace. In parallel to this
car manufacturers have been looking at ways to pass data about driving
conditions and behaviors
cars – an application known as Vehicle to Vehicle Communications or V2V. The aims
of V2V are to make driving safer and make road use more efficient. One approach
is to use the LED lights of a car to transmit some of this V2V communications
1. Testing of LI-FI transmitter and receiver module
proposed system requires a transmitter and a receiver in each vehicle in both
rear and front sides of the vehicle, hence we first need to test the
transmitter and receiver module successfully as they are the building block of
vehicle 1 is braking, the speed meter in the vehicle will be sensing that the
current speed is lower than the previous speed.
Fig1.V2V Communication via Light.
a message will be sent through the transmitter which is placed in the rear
lights to vehicle 2.The message will be received by vehicle 2 using the photodiode
which is placed at the front of vehicle 2. A notice of Slow DOWN will be
displayed in vehicle 2 using an LCD.
vehicle 1 is in T- cross section, it will keep sending its speed information to
vehicle 2 using the LED at the headlights. The speed information will be
received by the photodiode in vehicle 2 and is compared to vehicle 2 speed. If
vehicle 2 is about to cross the junction while vehicle 1 is moving with a high
speed, the driver will be alerted to check the other vehicle which is around in
Fig2.V2V Communication to avoid accidents
in T- junction
proposed use of Li-Fi technology in this paper comprises mainly light-emitting
diode (LED) bulbs as means of connectivity by sending data through light spectrum
as an optical wireless medium for signal propagation. In fact, the usage of LED
eliminates the need of complex wireless networks and protocols. There is a
great opportunity to improve road safety, vehicle efficiency and traffic management
by simply extending the capabilities and features that already exist on many
current vehicle designs.
function generator provides the PWM signal which drives the LED. Transistor
2N2222A acts as a small signal switch
Fig 2. The basic transmitter circuit is
given in Figure
Fig 3 The basic receiver
circuit is shown in Figure
On the receiver side, photodiode detects the photons and generates
current in the external circuit which is proportional to the incident power.
By creating an array of photo diode in parallel the current generated
can be increased. A trans-impedance amplifier which converts the generated
current into voltage is used. The signal received through photo detector is
very weak and it is in the m V range, so it needs to be amplified. Hence
voltage amplifier circuit is designed to amplify the detected voltage. The
LM324 is a low-cost, quad operational amplifiers. It has several distinct
advantages over standard operational amplifier types in single supply applications.
They operate at supply voltages in the range of 3.0 V to 32 V with quiescent
currents. An ADC is used to convert the analog voltage into digital output
which consists of transmitter in bit stream. Thus the transmitted signal is
recovered back at the receiver side.
Fig 4 Figure shows the output of the
The blinking of the LED is controlled by the signal generator, which
send a bit stream, e.g. 1010101010 and then changes the stream as 1111000011110000
based on the change in the speed of the vehicle.
Fig 5 Figure shows the output
of the receiver circuit.
Further, the output of the receiver circuit can be fed into the
microprocessor which changes into digital form and thus the transmitted data
can be recovered back at the receiver side.
Simulations show that the LEDs transmit the data in form of digital
sequence and photo diode receives the digital sequence without error. Thus we
conclude that the proposed design can be implemented in the cars to avoid
collisions. The cars alerting the driver can make the roads safer and reduce
the risk of loss of lives. The design is cost effective. However in real time
there can be disruptions in the transmission due to noise and attenuation in
which can be tackled by using novel modulation techniques which adds on to the
cost of the technology making it functional and effectual. A complete prototype
of the system will be implemented and tested to check the effectiveness of the
circuits in real time and to achieve the longest possible range for the
In conclusion, the concept of Li-Fi had been introduced along with
existing techniques and classical trends used for vehicle to vehicle
communications. Thus, V2V Communication will avoid severe road accidents and
work as an alternative to the more expensive radio system. The concept of LIFI
is currently attracting a great deal of interest, not least because it may
offer a genuine and efficient alternative to radio based wireless. As growing
number of people and their devices access wireless internet the air waves are
becoming increasingly clogged, making it more and more difficult to get a
reliable, high speed signal.
We extend our
gratitude towards our principal, Dr. B. K. Mishra. Under his helpful guidance
we could undertake this project and he also guided us in various areas in this
development. We are greatly indebted to our internal project guide Ms. Megha Gupta,for her guidance and constant supervision as well as providing
necessary information regarding the project and supporting us in our project.We
are also thankful to our Head of Department Prof. Vineet Dongre and Project
Co-coordinator Prof. Manoj Chavan & Prof Shailandra Shastri who have given
us constant motivation, guidance and encouragement for the project. We are also
grateful to our classmates and friends who have given us feedback and
encouragement. Finally we would wish to thank our college Thakur College of
Engineering and Technology for providing us with a platform and the necessary
facilities to make this project.
Survey on LIFI technology
Shivaji Kulkarni, Dept. of Electronics and Communication,
B.V.B. College of Engineering and Technology, Hubli, India
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