Detailed literature review on visible light communication

1. VISIBLE LIGHT
COMMUNICATION
ALWIN POULOSE
3MTCN,Dept.of ECE
Reg.No:1567001
Christ university
LITERATURE REVIEW
ON
MENTOR : Mr. Abhijith B N
Asst.Professor,
Dept. of E&C,
CUFE

2. CONTENTS
• ABSTRACT
• INTRODUCTION
• LITERATURE REVIEW
• PROBLEM IDENTIFICATION
• OBJECTIVES
• METHODOLOGY
• CONCLUSION
• BIBLIOGRAPHY

3. ABSTRACT
• The detailed study of VLC research, it was found that it can be used for various
applications.
• Applications include vehicle to vehicle data transmission using their headlights,
Position detection, intelligent transport system, and image sensor
communications, and internet access, audio and video transmission.
• From the survey on VLC, it shows VLC has great influence in future
communication areas and it can be easily implement on different applications.
• This literature review deals with the literature survey on visible light
communication and their applications and challenges.
• This literature review also discuss about the fundamental analysis of visible light
communication and Indoor Visible Light Communications challenges and
prospects. A MATLAB-based simulation program for indoor visible light
communication system and Real-time Audio & Video Transmission System
Based on Visible Light Communication are explained.
• For implementation MATLAB software is used and created a VLC system and
analyzed distribution of received power for one LED and four LED.

4. INTRODUCTION
• The idea of using light as a communication
medium was implemented by Alexander Graham
Bell in 1880 with his invention of the photo
phone, a device that transmitted a voice signal on
a beam of light.
• Bell focused sunlight with a mirror and then
talked into a mechanism that vibrated the mirror.
• The vibrating beam was picked up by the detector
at the receiving end and decoded back into the
voice signal, the same procedure as the phone did
with electrical signals.
• But Bell could not generate a useful carrier
frequency, nor was he able to transmit the light
beam from point to point.
• Obstacles in nature such as fog and rain which
could interfere with the photo phone made Bell
stop any future research into his invention.

5. • With the invention of LED (Light
Emitting Diode), the idea of using light
as a communication medium has started
again. VLC uses white Light Emitting
Diodes (LED), which send data by
flashing light at speeds undetectable to
the human eye.
• One major advantage of VLC is that we
can use the infrastructure around us
without having to make any changes to
it. LEDs’ ability to transfer information
signals over light (light which is between
400THz to 800THz of frequency and
whose wavelength is between 400nm to
700nm) makes it a very good
communication medium.
• Now the light we use in our daily life
can not only be used for providing light
but also for communication.
VLC Technology

6. LITERATURE REVIEW
[1] T. Komine and M. Nakagawa , “ Fundamental Analysis for Visible-Light
Communication System Using LED Lights ”, IEEE Transactions on Consumer
Electronics, Vol. 50, no. 1,pp. 100-107, February 2004.
In this paper, Toshihiko Komine and his student member had a fundamental analysis on VLC
system using LED lights. In which requirements for optical lighting and optical transmission
were discussed and an example of design was set up.
Optical Wireless Communication Design Setup

8. The distribution of received power
The distribution of received power
with reflection
• From their work they understood that the system made communication and
lighting possible and they discussed about the influence of reflection and inter
symbol interference.
• From their analysis they showed that the communication performance is
degraded severely by inter symbol interference.
• Finally they concluded that relation between the data rate and the FOV and
suggested the potential of high speed data transmission like 10 GB/s.

9. [2] P. Amirshahi (Member) and M. Kavehrad (FIEEE) “Broadband Access over
Medium and Low Voltage Power-lines and use of White Light Emitting Diodes for
Indoor Communications” (IEEE Communications Society subject matter experts for
publication in the IEEE CCNC 2006 proceedings.)
In this paper, P. Amirshahi and M. Kavehrad not only discussed the potential
capacities of emerging power line communications and white LED indoor
communications for broadband access, but also the fundamental analysis of VLC
systems using white LEDs. In which they designed a white LED system for lighting
and high data rate indoor communications in a model room such that there is no
blind spot in the room for data communications.
Optical Wireless Communication Design Setup

10. There are several important findings were in this paper:
1. If the receiver’s coverage area radius is greater than 2 meters, receivers at the
corners will at least receive one LOS signal from the closest transmitter.
2. The design for the receiver needs a field of view (FOV) equal or greater than 25
degrees.
3. Reflected signals have so much less power at the receiver compared to LOS path
signals is confirmed by the equation

11. In comparison to the study of previous paper (Toshihiko Komine
2004) which is using a simpler set-up, a conclusion can be drawn:
1. With an absence of blind spot in the room, this set up outshone
the model shown in a previous research in 2004 by Toshihiko
Komine
2. The study found that a wider FOV could certainly provide a
larger receiver area yet more complex.
3. A narrower FOV resulted in a smaller delay spread, caused by
reflections of the optical signals on the walls, in the channel.
4. To attain a higher data rate, impedance matching in the
network is necessary.

12. [3] Dominic O’Brien Hoa Le Minh, Lubin Zeng and Grahame Faulkner, Kyungwoo
Lee,Daekwang Jung, YunJe Oh, Eun Tae Won, “Indoor Visible Light
Communications: challenges and prospects”
• In this paper they explained the typical basic configuration, and the performance
available using simple modulation schemes for visible light communication
• Unmodified LEDs typically have modulation bandwidths of several MHz, but
typical lighting levels provide a communications channel with a Signal to Noise
Ratios in excess of 40dB.
• Different techniques can be used to improve the data rate and one of the
techniques is the equalization process.
• In this paper they explained several approaches to offer data rates of 100 Mb/s
and above.
Typical indoor environment

13. Characteristics of the modeled system
• In this work they also consider different parameters for improving data rates which
are: Optical filtering, Transmitter equalization, Receiver equalization, Optical
Multi-Input Multi-Output (MIMO) transmission.
• By analyzing these parameters they found how these are related to data rate and
they concluded by reporting future challenges.
• For achieving high data rates up to 100 Mb/s communications requires
equalization, complex modulation and signal processing or parallel
communications.
• Combinations of different techniques should allow much higher rates to be
achieved, up to Gb/s in some cases, although this will require more complex
systems.

14. [4] H.Q. Nguyen, J.H. Choi, M. Kang, Z. Ghassemlooy, D. H. Kim, S.K. Lim, T.G.
Kang, and C. G. Lee, “A MATLAB-based simulation program for indoor visible
light communication system”
• In this paper they report a simulation program for indoor visible light
communication environment based on MATLAB and Simulink.
• The program considers different positions of transmitter and the reflections at
each wall.
• For visible light communication environment, the illumination light-emitting
diode is used not only as a lighting device, but also as a communication device.
• Using the simulation program, calculates the illumination distribution, RMS
delay spread, and received signal waveform considering the positions of the
transmitters and the reflections on walls.
Indoor visible light communication environment

15. Simulation parameters The position of transmitters on the ceiling
Distribution of illuminance in case of
one transmitter
Illuminance distribution in case of 4
transmitters
After analyzing these Illuminance distributions they consider the Distribution
of RMS delay spread for one transmitter and four transmitters. They also
demonstrated the waveforms for NRZ-OOK using MATLAB/Simulink.

16. [5] Yingjie He, Liwei Ding, Yuxian Gong, Yongjin Wang, Real-time Audio & Video
Transmission System Based on Visible Light Communication, Optics and Photonics
Journal, 2013, 3, 153-157
• In this paper Real-time Audio & Video Transmission System Based on Visible
Light Communication presents a prototype of real-time audio and video
broadcast system using inexpensive commercially available light emitting diode
(LED) lamps.
• Their Experimental results showed that real-time high quality audio and video
with the maximum distance of 3 m can be achieved through proper layout of
LED sources and improvement of concentration effects.
• They designed and simulated the Lighting model within room environment which
indicates close relationship between layout of light sources and distribution of
illuminance.
• As compared to other papers, in this paper they explained the simulation of
illuminance distribution for two different light source arrangements is shown in
Figure
Square array (Left) & Round array (right).

17. • The corresponding Illuminance distribution with the LED semi-angle of 45
degree as shown in figure.
Illuminance distribution for 4x4
square deployment
Illuminance distribution for round
deployment.
• From the simulation results it is clear that the round array light sources
have less Illuminance distribution as compared to Illuminance distribution
for 4x4 square array light source.

18. [6] Penghua Lou, Hongming Zhang , Xie Zhang, Minyu Yao, Zhengyuan
Fundamental Analysis for Indoor Visible Light Positioning System.
• In this paper, they first demonstrate the indoor positioning system
prototype.
• Some numerical analyses for the proposed system were performed,
and a MATLAB–based simulation is made to study the
effectiveness and accuracy of positioning algorithm, the probability
distribution of detection and the acceptable movement speed.
• Thereafter, they concluded that their lab prototype basically
satisfies the required accuracy in some coarse location
environments.
• After studying the paper it is clear the concept of Fundamental
Analysis for Indoor Visible Light Positioning System.
• How the LED-ID technology used in visible light communication
into a kind of indoor positioning system also explained in the
paper.

19. From the detailed analysis, Penghua Lou and his team members reached the
following conclusions:
 The positioning accuracy, which is related to the effective positioning radius,
reaches 1.3m. It is less than that most of wireless location or infrared location
systems.
 If the receiver position is fixed, the detection depends on the pitch angle of the
receiver, which is defined as the probability distribution detection. The
probability is beyond 50% while the distance between the receiver and the
vertical projection of LED source is within the range of 1.08m.
 The normal movement speed in interior environment is completely acceptable
in their positioning system.

20. [7] Yang Liu,Kevin Liang,Hung-Yu Chen,Liang-Yu Wei,Chin-Wei Hsu,Chi-Wai
Chow,Chien-Hung Yeh, Light Encryption Scheme Using Light-Emitting Diode and
Camera Image Sensor, Volume 8, Number 1, February 2016.
• Yang Liu and his team members
proposed a Light Encryption
Scheme Using Light-Emitting
Diode and Camera Image Sensor.
• The original visible signal sending
from the lamp can be first
received by the proposed light
encrypter
• The information can be encrypted and then emitted. The light encrypter acts as an
encryption gateway for signals in optical domain.
• The rolling shutter effect of the complementary metal–oxide semiconductor
(CMOS) camera in the mobile phone can be used.
• By demodulating the rolling shutter pattern, the data information can be obtained.

21. [8] Hrushit Parikh , Jimesh Chokshi, Nimit Gala and Tanaji Biradar “Wirelessly
Transmitting a Gray scale Image Using Visible Light”
• This paper use common data encryption techniques followed by modulation of the signal
using Orthogonal Frequency Division Multiplexing.
• The modulated signal is used to drive common Light Emitting Diodes which transmit a
binary bit-stream in the form of light, through air as the medium.
• A photo detector, used at the receiver, along with a driver circuit and the appropriate
decryption block is used to get back the original data.
• In this paper shows how a regular gray scale image can be transmitted with this method
and faithful reproduction is achievable at the receiver.
• LED bulbs are used as transmitters and the intensity of the LEDs is varied at very high
rate, using OFDM modulation technique to encode the image data, such that the intensity
appears constant to the human eye.
• The sensitive receiver circuit is designed to detect these small instantaneous changes in
the LED intensity and hence decode the received data, thereby reproducing the image in
its original quality.

22. Modulation and transmission. The LED is biased before applying the OFDM signal
Receiver block diagram to demodulate the OFDM signal.

23. [9] Farag Mousa,Tran The Son, Andrew Burton, Hoa Le Minh, Zabih Ghassemlooy,
Trung Q. Duong, Anthony C.Boucouvalas,Joaquin Perez, and Xuewu Dai1
“Investigation of Data Encryption Impact on Broadcasting Visible Light
Communications” 2014 IEEE
• This paper investigates the impact of data encryption and decryption in
indoor broadcasting visible light communications (VLC) system embedded
in the physical layer.
• The RSA encryption has been implemented to provide a secure data
transmission in the physical layer.
• The paper shows that the bit error rate (BER) performance for the un-
secured and secured VLC systems (8 and 12-bit) for data rates of 2 and 12
Mbps.

24. • The results showed that the
block error severely affected
the system BER performance
especially for the 16-bit
encryption key length.
• The power penalties observed
were ~1.2 dB and ~1.75 dB
for the 8-bit and 16-bit
encryption key lengths,
respectively within the 3 dB
LED bandwidth
Block diagram of RSA applied in VLC system

25. PROBLEM IDENTIFICATION
• From the literature survey it is clear many interesting things related to visible
light communication.
• Literature survey also explains the concept of fundamental analysis for visible-
light communication system using LED lights, Indoor Visible Light
Communications challenges and prospects, A MATLAB-based simulation
program for indoor visible light communication system, Real-time Audio &
Video Transmission System Based on Visible Light Communication and Light
Encryption Scheme Using Light-Emitting Diode and Camera Image Sensor.
• In addition to that it is found some of the challenges faced by today’s engineers
in implementing VLC system for various applications. Few among them are:
High Data Rate
Uplink Issue
Regulatory Issues
Line of sight
Range (distance between transmitter and receiver)
Interference from other light source like sun, fluorescent lamp, etc.
Secure data communication

26. • Beyond these problems secure data communication is the major
problem.
• To overcome this problem I am planning to carry out research with
the following problem statement which involves light encryption
for visible light communication.
Problem Statement
Light encryption for visible light communication
1. A encryption scheme which affects least by noise
2. Noise Removal - Estimation of noise
3. Independent of the position of the noise source.

27. OBJECTIVES
• Implementing different VLC model
• Simulate Illuminance distribution in case of different transmitters.
• Simulate the distribution of received power with reflection.
• Simulate the distribution of RMS delay spread for different
transmitters.
• Analyze the simulation results.
• Analyze the different light source arrangements and their
Illuminance distribution.
• Analyze the current light encryption schemes used in visible light
communication
• Propose a new light encryption method for visible light
communication

28. METHODOLOGY
• Conducting detailed literature survey on light
encryption for visible light communication.
• Usage of Matlab and Simulink software for
implementing of VLC system and for simulation of
Illuminance distribution of different transmitters.
• Demonstrate the proposed new light encryption method
for visible light communication.

29. CONCLUSION
• VLC technology has a bright scope in future.
• This technology demonstrated a solution to the problem of integrating Visible
Light Communication technology with present infrastructure, without having to
make major changes to that infrastructure. .
• Visible Light Communication is a rapidly growing segment of the field of
communication.
• There are many advantages to using VLC.
• There are also many challenges.
• VLC will be able to solve many of the problems people have been facing for
many years, mainly environmental and power usage issues.
• The preliminary literature survey is carried out to identify the problem statement,
to define objectives, and methodology to be followed and to find suitable
resource requirements and access to the resources.
• This phase helped me a lot in understanding the basic concepts of visible light
communication and their problems and challenges.
• It also helped me to create a timeline which can be a guideline to complete my
objectives.

30. REFERENCE
[1] Dominic O’Brien Hoa Le Minh, Lubin Zeng and Grahame Faulkner, Kyungwoo
Lee,Daekwang Jung, YunJe Oh, Eun Tae Won, “ Indoor Visible Light
Communications: challenges and prospects.”
[2] H.Q. Nguyen, J.H. Choi, M. Kang, Z. Ghassemlooy, D. H. Kim, S.K. Lim, T.G. Kang,
and C. G. Lee, “A MATLAB-based simulation program for indoor visible light
communication system.”
[3] P. Amirshahi and M. Kavehrad, “Broadband Access over Medium and Low Voltage
Power-lines and use of White Light Emitting Diodes for Indoor Communications.”
[4] Penghua Lou, Hongming Zhang , Xie Zhang, Minyu Yao, Zhengyuan Fundamental
Analysis for Indoor Visible Light Positioning System.”
[5] Toshihiko Komine,Masao Nakagawa, “ Fundamental Analysis for Visible-Light
Communication System using LED Lights”, IEEE Transactions on Consumer
Electronics, Vol. 50, No. 1, FEBRUARY 2004
[6] Yang Liu,Kevin Liang,Hung-Yu Chen,Liang-Yu Wei,Chin-Wei Hsu,Chi-Wai
Chow,Chien-Hung Yeh, “Light Encryption Scheme Using Light-Emitting Diode and
Camera Image Sensor”, Volume 8, Number 1, February 2016.
[7] Yingjie He, Liwei Ding, Yuxian Gong, Yongjin Wang, “Real-time Audio & Video
Transmission System Based on Visible Light Communication”, Optics and
Photonics Journal, 2013, 3, 153-157
[8] Hrushit Parikh , Jimesh Chokshi, Nimit Gala and Tanaji Biradar “Wirelessly Transmitting a
Gray scale Image Using Visible Light”.
[9] Farag Mousa,Tran The Son, Andrew Burton, Hoa Le Minh, Zabih Ghassemlooy, Trung Q. Duong,
Anthony C.Boucouvalas,Joaquin Perez, and Xuewu Dai1 “Investigation of Data Encryption Impact on
Broadcasting Visible Light Communications” 2014 IEEE