VISIBLE LIGHT COMMUNICATION BASED DATA TRANSMISSION

International Conference on Emerging Engineering Trends and Science(ICEETS-2016)

ISSN : 2348 – 8549 www.internationaljournalssrg.org Page 198

VISIBLE LIGHT COMMUNICATION BASED

DATA TRANSMISSION SYSTEM USING Li-Fi

K.Priyanka,S.Priyanka and G.G.Renuga Devi Student, Department of Electronics and

Communication Engineering P.S.R.Rengasamy college of engineering for women, Sivakasi, Tamil Nadu, India

Abstract Visible Light Communication (VLC) based on white

Light Emitting Diodes (LEDs) is promising for realiz ing

ubiquitous wireless networks, since LEDs would be used for

both illumination and wireless transmission simultaneously. In

our project, we are going to implement visible light

communication for data transmission from one PC to another

PC. Visible Light Communication (VLC) is an emerging fie ld

in O ptical Wireless Communication (OWC) which utilizes the

superior modulation bandwidth of Ligh t Emitting Diodes

(LEDs) to transmit data. In modern day communication

systems, the most popular frequency band is Radio Frequency

(RF) mainly due to little interference and good coverage.

However, the rapidly dwindling RF spectrum along with

increasing wireless network traffic has substantiated the need

for greater bandwidth and spectral relief. By combining

illumination and communication, VLC provides ubiquitous

communication while addressing the shortfalls and limitations

of RF communication. In this project, we have implemented a

system which can transmit and receive data by using visible

light communication. We have also discussed about working,

features and implementation of visible light communication in

our system. The recent progress made by various research

groups in this fie ld is discussed along with the possible

applications of this technology. Finally, the limitations of VLC

as well as the probable future directions are presented. Keywords Visible light communication; Light Fidelity(Li-Fi);

Wireless Fidelity(Wi-Fi); Solar panel; Data transmission.

I. INTRODUCTION

In earlier days the system size is very large, so it is difficult to use. Hence we go for embedded system. Embedded system seems to be used in all places. It is a fast growing technology in various fields like automation, home appliances, automobiles, aeronautics etc., After using embedded system, we dump the large program into small chip and it reduce the size of the system. It provides real time response. So embedded system is referred to as real time operating system. Visible light provides about 400THz unlicensed and secure and radio-free media for wireless communications. The bandwidth of visible light is over 1000 times wider than all the previously used radio frequencies together which allows enormous capacity for communications purposes. A human eye is sensitive only to the visible light part of the electromagnetic spectrum

Ms. T. Karpagadevi M.E.,(AP/ECE)

Assistant Professor, Department of Electronics and Communication Engineering

P.S.R.Rengasamy College of Engineering for Women

Sivakasi, India. between ultraviolet and infrared spectrum. The whole spectrum between wavelength of 380 to780 nanometers can be used for the VLC. VLC facilitates the reuse of existing lighting infrastructure for the purpose of communication. This means that such systems can be deployed with relatively lesser efforts and at a lower cost. In our project we are going to implement, visible light communication for eco-friendly data transmission. VLC offers secure communication between the rooms because it can be easily blocked by walls. These days LEDs are used in many places such as traffic lights, automobiles indoor and outdoor lightning. On-off transient time of LED is short which offers high data transmission in VLC. II. VISIBLE LIGHT COMMUNICATION SYSTEM

This section provides an over view of data transmission in VLC. VLC uses white LEDs, where the data transmitted using intensity modulation (IM) technique. The detected intensity is converted as electrical signal by photo detector. This process is called direct detection (DD).

TRANSMITTER

DATA TRANSMITTER

CIRCUITARY LED

OPTICAL

MEDIUM

RECEIVER

(AIR)

DATA RECEIVER SOLAR

CIRCUITARY PANEL

Figure.1.Visible Light Communication System



International Conference on Emerging Engineering Trends and Science (ICEETS-2016)

A.WHITE LED TRANSMITTER

Light emitting diode is two lead semi conductor device that emits visible light when electrical current passes through it. It is a PN junction diode which emits light, when a suitable voltage is applied to the lead, electrons are able to recombine with electron holes with in a device and releasing energy form of protons. Older LED made up of gallium arsenide (red and green) semi conductor material. Present LED is made up of P-phenylenevinylene (any color) synthetic material. It works on principle of electro luminescene. It offers advantageous properties such as high brightness, low power consumption, reliability and long life time. B.ILLUMINANCE OF LED LIGHTING

The illuminance expresses the brightness of an illuminated surface. The luminous intensity in angle ϕ is given by,

I(ϕ)=I(0)cosm

(ϕ). (1) A horizontal illuminance Ehor at a point (x,y) is given by

Ehor =I(0)cosm(ϕ)/d

2.cos(ø) (2)

where I(0) is the center luminous intensity of an LED, ϕ is the angle of irradiance, ø is the angle of incidence, and d is the distance between an LED and a detector's surface. C.OPTICAL SOURCE

Two methods are typically used for the generation of white light. Mixing specified quantities of Red, Blue and Green colour that yields white light. The major reason for not using RGB LEDs in general lighting is that the junctions that produce and green light are not as efficient as the junction that produces blue light. Efficiency of blue light is about 80% whereas it is only it is only about 60% and 30% for red and green light respectively. Furthermore this technique has certain packaging and electronic complexities which make it a less favourable technique. More attractive technique is known as phosphor based white LED. HBLEDs that produce white light do indeed produce a blue light. However, the phosphor (which is predominantly yellow) only converts part of the blue light. The converted and non-converted parts are mixed to obtain the desired shade of white.

Talking of VLC based communication system focuses on investigating two basic properties of LED i.e. luminous intensity (i.e. energy flux per solid angle) and transmitted optical power (i.e. total energy radiated from optical source).Mathematically, we can express luminous intensity I by equation[3],

I= _ ∫ _ ( ) ( ) _ (3)

where φe is the energy flux, V(λ) is standard luminosity

curve and λ is the maximum visibility. D.LOS CHANNEL MODEL

In order to achieve high data rate there must be proper Line Of Sight (LOS) between the transmitter and receiver. The non-directed LOS or diffused lightning achieves only limited data rate. In NLOS case, the light is reflected by walls and any other obstacles.

r

α D RX

TX β

θ

Figure.4.LOS Channel Model

III.EXISTING SYSTEM

A simple, off-the-shelf LED can be used not only as a light emitter but can also replace photo detectors and fulfill their task as a light receiver. We consider that each device is equipped with one LED that is used for both transmission and reception. We now focus on the description of the receiver design, assuming that the sender transmits a periodic idle pattern, an optical signal with period 500s consisting of no-light(corresponding to 2 symbols ’0’) and light (corresponding to 2symbols ’1’) slots. The resulting signal frequency is 1 kHz, and this value is chosen because most humans are sensitive to light flickering below 1 kHz. To prevent flickering and brightness changes due to the transmission of other messages than the idle pattern, such as data messages, we use Manchester Coding to distribute the occurrences of ’1’ and ’0’ more evenly the human observer will perceive an

always-on optical signal. The LED-to-LED communication enables new

mobile applications for entertaining and creative use cases and provides a low-cost, low-complexity path to light communication. Visible light is already often part of our environments, so VLC provides a unique opportunity to provide communication capabilities that is not noticed. However, VLC requires cost-effective platforms, and this paper describes a simple design that leverages modern microcontrollers to overcome the limitations of simple, mass-produced LEDs. IV.PROPOSED SYSTEM

In the proposed system, we have used visible light communication for data transmission from one PC to



another PC. The entire system consists of two sections, the transmitter section and receiver section.



International Conference on Emerging Engineering Trends and Science (ICEETS-2016) A.VLC TRANSMITTER SYSTEM

The transmitter section consists of AT89S52 microcontroller, Visible light communication transmission module, UART cable and PC. We use hyper terminal software to write and save the data that we enter. That data will be transferred through visible light communication. In the hyper terminal, we have to open a new connection, to enter the data. We have to give a connection name, and port number, to which the microcontroller is connected. The USB to Serial cable is used to connect PC and Microcontroller. The microcontroller has the serial port and PC, now-a-days come with USB port. To connect the two, we have to use USB to Serial cable. In the hyper terminal, the new connection will be created between the PC and the microcontroller. The hyper terminal file can be saved. Whatever the data we enter in the hyper terminal, the data will be send to the microcontroller through serial communication. The microcontroller receives the characters in eight bits as per the ASCII Table. The microcontroller then sends the data to the receiver through visible light communication transmission module. The data is modulated to light source. B.VLC RECEIVER SYSTEM

The receiver section consists of Visible light receiver module, AT89S52 microcontroller, and PC. The received light source is detected by the photo detector and demodulated to data. The received data is read by the microcontroller as eight bits as per ASCII Table. The microcontroller then sends the data through serial communication to the PC. The connection between microcontroller and PC is done by USB to Serial cable. The received data will be displayed in the hyper terminal, for which we have to establish a new connection and set the port number. Whatever the characters received from the microcontroller, it will be displayed in the hyper terminal.

Figure.2.VLC Transmitter System

Figure.3.VLC Receiver System

V.APPLICATIONS

As far as LEDs based system applications are

concerned, their domain is very versatile ranging from commercial purpose, academic and industrial application. From inner satellite to military purpose, from hospitals (where electromagnetic interference must be avoided) to aircrafts, from lighting to automobiles, In Petrochemical plant Li-Fi system is used. As a remote control device under the ocean.

VI.CONCLUSION

This 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. VLC is still in its beginning stages, but improvements are being made rapidly, and soon this technology will be able to be used in our daily lives. In spite of the research problems it is our belief that the VLC system will become one of the most promising technologies for the future generation in optical wireless communication.

REFERENCES [1]. K.Sindhubala and B.Vijayalakshmi,‖Eco friendly data transmission in

visible light communication‖,IEEE Standard,2015



International Conference on Emerging Engineering Trends and Science (ICEETS-2016) [2] IEEE Standard for Local and Metropolitan Area Networks—Part 15.7: Short-Range Wireless Optical Communication Using Visible Light, pp. 1– 309, Sept.2011. [3] T. Komine and M. Nakagawa, ― Integrated system of white LED visible-light communication and power-line communication,‖ IEEE Trans.

Consum. Electron, vol. 49, pp. 71–79, Feb. 2003. [4] M.Saadi, L. Wattisuttikulkij, Y. Zhao, P. Sangwongngam, ― Visible

Light Communication: Opportunities, Challenges and Channel Models‖,

International Journal of Electronics and Informatics, vol.2, Feb.2013. [5] M.Shahin Uddin, J.Sang Cha, J.Young Kim and Y. Min Jang― Mitigation Technique for Receiver Performance Variation of Multi-Color Channels in Visible Light Communication‖, Sensors Journal, vol.11,pp.6131-6144,June.2011. [6] S. Kim, J.S Won, S.H Nahm, ― Simultaneous Reception of Visible Light

Communication and Optical Energy using a Solar Cell Receiver ‖ICT

convergence(ICTC),pp.896-897,Oct.2013. [7] S.Haruyama, ― Advances in Visible Light Communication Technologies‖ ECOC Technical Digest, 2012. [8] M.Syuhaimi Ab-Rahman, L. Al-Hakim Azizan, H.Ramza and Z.Musa, ― The Comparison of Experimental and Analytical Study of the Gaussian

Intensity Distribution for Light Emitting Diodes Beam‖, Journal of Computer Science,vol.8,pp.913-919, 2012.

[9] W. M. T. Vijayananda, K. Samarakoon, and J. Ekanayake, "Development of a demonstration rig for providing primary frequency response through smart meters," international Universities Power Engineering Conference, Cardiff Wales, Aug. 31- Sept. 3, 2010,pp. 1-6. [10] A. Jovicic,L. Junyi,and T. Richardson, "Visible light communication: opportunities, challenges and the path to maret," in IEEECommunication Magazine, vol. 51,no. 12,pp. 26-32,Dec. 2013. [11] E. Pisek, S. Rajagopal, and S. Abu-Surra, "Gigabit rate mobile connectivity through visible light communication," iEEE international Cotifrence on Communications, Ottawa, ON, June 10-15, 2012, pp. 3122-3127. [12]Y. F. Liu,C. H. Yeh,C. W. Chow,Y. Liu,Y. L. Liu,an H. K. Tsang,"Demonstration of bi-directional LED visible light communication using TOD traffic with mitigation of reflection interference," in Optics Express, vol. 20,pp. 23091-23024,8 Oct. 2012.

Documents

VISIBLE LIGHT COMMUNICATION BASED DATA TRANSMISSION