LIFI technology

Li-Fi Technology

2015-16

VISVESVARAYA VISVESVARAYA TECHNOLOGICAL UNIVERSITY, BELAGAVI

A Seminar Report On

Li-Fi Technology

Submitted By ASHWATH A

4NI13IS020

Under the guidance of Mrs.C.K Vanamala Associate Professor Professor Dept of ISE NIE, Mysore Mysore

The National Institute of Engineering (Autonomous Institution)

Department of Information Science and Engineering MYSORE – MYSORE – 570008 570008 Dept of Information Science and Engineering

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Li-Fi Technology

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THE NATIONAL INSTITUTE OF ENGINEERING MYSORE-570008

Department of Information Science and Engineering

Certificate Certifies that the seminar work entitled ―Li-Fi Technology ‖ is a work carried out by ASHWATH A bearing 4NI13IS020 in partial fulfilment for the seminar prescribed by National

Institute Of Engineering, Autonomous Institution under Vishvesvaraya Technological University, Belagavi, for the Eighth Eighth Semester B.E Information Science & Engineering. It is certified that all correction/suggestions indicated for Internal Assessment have been incorporated. The Seminar report has been approved as it satisfies the academic requirements in respect of the seminar work prescribed for the Eight Semester.

Signature of Guide (Mr. Guide)

Dept of Information Science and Engineering

Signature of HOD (Dr. K. Raghuveer)

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ABSTRACT

Li-Fi is a new wireless technology to provide the connectivity with in localized network environment. The main principle of this technology is we can transmit the data using light illumination by using light-emitting diodes where radio frequency is media in Wi-Fi and LED bulb light intensity is faster than human eye can follow. Prof Harald Haas an expert in optical wireless communications at the University of Edinburgh, he was demonstrated how an LED bulb equipped with signal processing technology could stream a high-definition video to a computer. By using this technology a one- watt LED light bulb would be enough to provide net connectivity to four computers. He coined the term "light fidelity" or li-fi and set up a private company, Pure VLC, to exploit the technology. . He envisions a future where data for laptops, smart phones, and tablets is transmitted through the light in a room. And security would be snap – if you can‘t see the light, you can‘t access the data. Keywords: Li-fi, Wi-fi, LED, VLC.


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ACKNOWLEDGEMENT The seminar report on “Li-Fi Technology” is outcome of guidance, moral support and devotion bestowed on me throughout my work. For this I acknowledge and express my profound sense of gratitude and thanks to everybody who have been a source of inspiration during the seminar preparation. First and foremost I offer our sincere phrases of thanks with innate humility to Mrs.C.K Vanamala, Associate Professor of National Institute of Engineering, Bareilly and guide of my seminar for providing help whenever needed. If I can say in words I must at the outset tender our intimacy for receipt of affectionate care to National Institute of Engineering for providing such a stimulating atmosphere and wonderful work environment.

ASHWATH A


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CONTENTS Page No 1. Introduction

7

1.1 Objective

7

1.2 Scope of Li-Fi

8

1.3 System Analysis

8

1.3.Wi-Fi Technology

8

1.3.2 Disadvantages of Wi-Fi 1.4 Li-Fi Technology 1.4.1 Advantages of Li-FI

2. Literature survey

8 8 8

9

2.1 Wi-Fi

9

2.2 Li-Fi

9

3. Genesis of Li-Fi

10

4.Li-Fi Requirements and Specification

11

4.1 Requirements 5. Li-Fi Architecture

11 12

5.1 Basic Architecture

12

5.2 Function of the Bulb

13

6. Working Principle of Li-Fi

14-16

7. Applications of Li-Fi

17-19

8. Lifi vs Wi-fi

20

9. Conclusion

21

References

21


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LIST OF FIGURES Figure no. 2.2

3.1a

Figure Description Li-Fi as a superset of different optical wireless technologies involving communication, positioning, natural user interfaces and many more.

Harald haas

Page no. 9

10

3.1b LED

10

4.1a Requirements of Li-Fi

11

5.1a

Basic Architecture

12

5.2a

Functionality of Bulb

13

6.1a

Visible light communication (VLC) 15 Typical Example of Visible light

6.1b

communication: Use of LED

16

illumination as a transmitter

8.1a

Lifi vs Wifi


20

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Chapter 1

INTRODUCTION LiFi is transmission of data through illumination by taking the fiber out of fiber optics by sending data through a LED light bulb that varies in intensity faster than the human eye can follow.Li-Fi is the term some have used to label the fast and cheap wireless-communication system, which is the optical version of Wi-Fi.

The term was first used in this context by Harald Haas in his TED Global talk on Visible Light Communication. ―At the heart of this technology is a new generation of high brightness lightemitting diodes‖, says Harald Haas from the University of Edinburgh, UK,‖Very simply, if the LED is on, you transmit a digital 1, if it‘s off you transmit a 0,‖Haas sa ys, ―They can be switched on and off very quickly, which gives nice opportunities for transmitted data.‖It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s.

University of Oxford and the University of Edingburgh are focusing on parallel data transmission using array of LEDs, where each LED transmits a different data stream. Other group are using mixtures of red, green and blue LEDs to alter the light frequency encoding a different data channel.Li-Fi, as it has been dubbed, has already achieved blisteringly high speed in the lab. Researchers at the Heinrich Hertz Institute in Berlin,Germany,have reached data rates of over 500 megabytes per second using a standard white-light LED. In October 2011 a number of companies and industry groups formed the Li-Fi Consortium, to promote high-speed optical wireless systems and to overcome the limited amount of radio-based wireless spectrum available by exploiting a completely different part of the electromagnetic spectrum. The consortium believes it is possible to achieve more than 10 Gbps, theoretically allowing a high-definition film to be downloaded in 30 seconds.

1.1OBJECTIVE 

Issues regarding radio spectrum,such as capacity, availability,efficiency, security are solved using LIFI



To increase the Speed of Data Transmission(upto 100gbps).


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1.2 SCOPE OF Li-Fi Given the bandwidth crunch being faced, Li-Fi provides a great solution as it uses optical spectrum instead of radio spectrum. Also, LED-based technolo gy is tantalizingly close tosolving both the indoor location problem (accuracy and information update intervals) and also high speed data communications , using an infrastructure that has already been deployed primarily for lighting purposes. Despite a number of fundamental barriers, companies can see the benefits of ubiquitous indoor centimeter level accuracy with millisecond updates that Li-Fi is p romising.

1.3 System Analysis 1.3.1 Wifi technology 

Wi-Fi is to hide complexity by enabling wireless access to applications and data, media and streams



It uses radio waves to transmit the data.



Through wifi Technology we can transfer data in terms of kbps/mbps.

1.3.2Disadvantages of wifi technology 

Wi-Fi has a limited radius of action and it is suitable for home networking, which is more dependent on the environment.



Data Reliability,speed,Accuracy are less in Wifi as it make use of Radio waves.

1.4 lifi technology     

Light Based Wifi . Light is used instead of radio-waves to transmit information Transceiver fitted LED lamps acts like Wi-Fi modems LED lamps can light a room as well as transmit-receive information Provides illumination as well as data communication

1.4.1 Advantages in lifi technology 

Li- Fi uses light rather than radio frequency signals so are intolerant to disturbances.



Li-Fi ensures reliability,accuracy,and high speed.


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Chapter 2

LITERATURE SURVEY 2.1 wi-Fi Most of us are familiar with Wi-Fi (Wireless Fidelity), which uses 2.4-5GHz RF to deliver wireless Internet acess around our homes, schools, offices and in public places. We have become quite dependent upon this nearly ubiquitous service. But like most technologies, it has its limitations.

Disadvantage While Wi-Fi can cover an entire house, its bandwidth is typically limited to 50-10 megabits per second (Mbps) today using the IEEE802.1n standard. This is a good match to the speed of most current Internet services, but insufficient for moving large data files like HDTV movies, music libraries and video games. The more we become dependent upon ‗the cloud‘ or our own ‗media servers‘ to store all of our files, including movies, music, pictures and games, the more we will want bandwidth and speed. Therefore RF based technologies such as today‘s Wi-Fi are not the optimal way. In addition, Wi-Fi may not be the most efficient way to provide new desired capabilities such as precision indoor positioning and gesture recognition.

2.2 Li-Fi Optical wireless technologies, sometimes called visible light communication (VLC), and more recently referred to as Li-Fi (Light Fidelity), on the other hand, offer an entirely new paradigm in wireless technologies in terms of communication speed, flexibility and usability.

Fig. 2.2: Li-Fi as a superset of different optical wireless technologies involving communication, positioning, natural user interfaces and many more.


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Chapter 3 Genesis of Li-Fi

Harald Haas, a professor at the University of Edinburgh who began his research in the field in 2004, gave a debut demonstration of what he called a Li-Fi prototype at the TEDGlobal conference in Edinburgh on 12th July 2011. He used a table lamp with an LED bulb to transmit a video of blooming flowers that was then projected onto a screen behind him. During the event he periodically blocked the light from lamp to prove that the lamp was indeed the source of incoming data. At TEDGlobal, Haas demonstrated a data rate of transmission of around 10Mbps -- comparable to a fairly good UK broadband connection. Two months later he achieved 123Mbps.

3.1a Harald haas Back in 2011 German scientists succeeded in creating an800Mbps (Megabits per second) capable wireless network by using nothing more than normal red, blue, green and white LED light bulbs (here), thus the idea has been around for awhile and various other global teams are also exploring the possibilities. Fig 3.1b LED


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Chapter 4

LiFi Requirements and Specification Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. This very property of optical current is used in Li-Fi setup. The operational procedure is very simple-, if the LED is on, you transmit a digital 1, if it‘s off you transmit a 0. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data. Hence all that is required is some LEDs and a controller that code data into those LEDs. All one has to do is to vary the rate at which the LED‘s flicker depending upon the data we want to encode. Further enhancements can be made in this method, like using an array of LEDs for parallel data transmission, or using mixtures of red, green and blue LEDs to alter the light‘s frequency with each frequency encoding a different data channel. Such advancements promise a theoretical speed of 10 Gbps – meaning one can download a full high-definition film in just 30 seconds..

4.1 Requirements • Bulb • RF power amplifier circuit (PA) • Printed circuit board (PCB) • Enclosure fig4.1a Requirements Li-Fi


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Chapter 5

Li-Fi ARCHITECTURE 5.1 Basic Architecture

Fig 5.1a The PCB controls the electrical inputs and outputs of the lamp and houses the microcontroller used to manage different lamp functions. An RF (radio-frequency) signal is generated by the solid-state PA and is guided into an electric field about the bulb. The high concentration of energy in the electric field vaporizes the contents of the bulb to a plasma state at the bulb‘s center; this controlled plasma generates an intense source of light. All of these subassemblies are contained in an alu minum enclosure.

5.2 FUNCTION OF THE BULB:At the heart of LIFI is the bulb sub-assembly where a sealed bulb is embedded in a dielectric material. This design is more reliable than conventional light sources that insert degradable electrodes into the bulb. The dielectric material serves two purposes; first as a waveguide for the RF energy transmitted by the PA and second as an electric field concentrator that focuses energy in the bulb. The energy from the electric field rapidly heats the material in the bulb to a plasma state that emits light of high intensity and full spectrum. Dept of Information Science and Engineering

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Fig 5.2a functionality of Bulb To further get a grasp of Li-Fi consider an IR remote.(fig 3.3). It sends a single data stream of bits at the rate of 10,000-20,000 bps. Now replace the IR LED with a Light Box containing a large LED array. This system, fig 3.4, is capable of sending thousan ds of such streams at very fast rate.


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CHAPTER 6

Working Prinicple of Li-fi

This brilliant idea was first showcased by Harald Haas from University of Edinburgh, UK, in his TED Global talk on VLC. He explained,‖ Very simple, if the LED is on, you transmit a digital 1, if it‘s off you transmit a 0. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data.‖ So what you require at all are some LEDs and a controller that code data into those LEDs. We have to just vary the rate at which the LED‘s flicker depending upon the data we want to encode. Further enhancements can be made in this method, like using an array of LEDs for parallel data transmission, or using mixtures of red, green and blue LEDs to alter the light‘s frequency w ith each frequency encoding a different data channel. Such advancements promise a theoretical speed of 10 Gbps – meaning you can download a full high-definition film in just 30 seconds. Simply awesome! But blazingly fast data rates and depleting bandwidths worldwide are not the only reasons that give this technology an upper hand. Since Li-Fi uses just the light, it can be used safely in aircrafts and hospitals that are prone to interference from radio waves. This can even work underwater where Wi-Fi fails completely, thereby throwing open endless opportunities for military operations. Imagine only needing to hover under a street lamp to get public internet access, or downloading a movie from the lamp on your desk. There's a new technology on the block which could, quite literally as well as metaphorically, 'throw light on' how to meet the ever-increasing demand for highspeed wireless connectivity. Radio waves are replaced by light waves in a new method of data transmission which is being called Li-Fi.Light-emitting diodes can be switched on and off faster than the human eye can detect, causing the light source to appear to be on continuously. Light-emitting diodes (commonly referred to as LEDs and found in traffic and street lights, car brake lights, remote control units and countless other applications) can be switched on and off faster than the human eye can detect, causing the light source to appear to be on continuously, even though it is in fact 'flickering'. This invisible on-off activity enables a kind of data transmission using binary codes: switching on an LED is a logical '1', switching it off is a logical '0'. Information can therefore be encoded in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. This method of using rapid pulses of light to transmit information wirelessly is technically referred to as Visible Light Communication (VLC), though it‘s potential to compete withconventional Wi-Fi has inspired the popular characterization Li-Fi. Visible light communication (VLC)- “A potential solution to the global wireless spectrum shortage”

LiFi (Light Fidelity) is a fast and cheap optical version of Wi-Fi, the technology of which is based on Visible Light Communication (VLC).VLC is a data communication medium, which uses visible light between 400 THz (780 nm) and 800 THz (375 nm) as optical carrier for data transmission and illumination. It uses fast pulses of light to transmit information wirelessly. The main components of this communication system are 1) a high brightness white LED, Which acts as a communication source and 2) Dept of Information Science and Engineering

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a silicon photodiode which shows good response to visible wavelength region serving as the receiving element? LED can be switched on and off to generate digital strings of 1s and 0s. Data can be encoded in the light to generate a new data stream by varying the flickering rate of the LED. To be clearer, by modulating the LED light with the data signal, the LED illumination can be used as a communication source. As the flickering rate is so fast, the LED output appears constant to the human eye. A data rate of greater than 100 Mbps is possible by using high speed LEDs with appropriate multiplexing techniques. VLC data rate can be increased by parallel data transmission using LED arrays where each LED transmits a different data stream. There are reasons to prefer LED as the light source in VLC while a lot of other illumination devices like fluorescent lamp, incandescent bulb etc. are available.

6.1aVisible light communication (VLC)-―A potential solution to the global wireless spectrum shortage‖


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Fig. 6.1b Typical Example of Visible light communication: Use of LED illumination as a transmitter


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Chapter 7 APPLICATIONS OF Li-Fi Technology 

Airways:-

Whenever we travel through airways we face the problem in communication media ,because the whole airways communication are performed on the basis of radio waves. To overcomes this drawback on radioways ,li-fi is introduce.



Green information technology:Green information technology means that unlike radiowaves and other communication waves affects on the birds , human bodys etc. Li-Fi never gives such side effects on any living thing.


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Free From Frequency Bandwidth Problem:-

Li-fi is an communication media in the form of light ,so no matter about the frequency bandwidth problem . It does not require the any bandwidth spectrum i.e. we don‘t need to pay any amount for communication and licence. 

Increase Communication Safety:-

Due to visual light communication , the node or any terminal attach to our network is visible to the host of network . 

Multi User Communication:-

Li-Fi supports the broadcasting of network , it help s to share multiple thing at a single instance called broadcasting. 

Lightings Points Used as Hotspot:-

Any lightings device is performed as a hotspot it means that the light device like car lights, ceiling lights , street lamps etc area able to spread internet connectivity using visual light communication. Which helps us to low cost architecture for hotspot. Hotspot is an limited region in which some amount of device can access the internet connectivity . 

Smarter Power Plants: Wi-Fi and many other radiation types are bad for sensitive areas. Like those surrounding power plants. But power plants need fast, inter-connected data systems to monitor things like demand, grid integrity and (in nuclear plants) core temperature. The savings from proper monitoring at a single power plant can add up to hundreds of thousands of dollars. Li-Fi could offer safe, abundant connectivity for all areas of these sensitive locations. Not only would this save money related to currently implemented solutions, but the draw on a power plant‘s own reserves could be lessened if they haven‘t yet converted to LED lighting.


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Undersea Awesomeness:-

Underwater ROVs, those favourite toys of treasure seekers and James Cameron, operate from large cables that supply their power and allow them to receive signals from their pilots above. ROVs work great, except when the tether isn‘t long enough to explore an area, or when it gets stuck on something.If their wires were cut and replaced with light — say from a submerged, high-powered lamp — then they would be much freer to explore. They could also use their headlamps to communicate with each other, processing data autonomously and referring findings periodically back to the surface, all the while obtaining their next batch of orders.

It Could Keep You Informed and Save Lives Say there‘s an earthquake in New York. Or a hurricane. Take your pick — it‘s a wacky city. The average New Yorker may not know what the protocols are for those kinds of disasters. Until they pass under a street light, that is. Remember, with Li-Fi, if there‘s light, you‘re online. Subway stations and tunnels, common dead zones for most emergency communications, pose no obstruction. Plus, in times less stressing cities could opt to provide cheap high -speed Web access to every street corner. USES IN VARIOUS AREAS

Can be used in the places where it is difficult to lay the optical fiber like h ospitals. In operation theatre LiFi can be used for modern medical instruments. In traffic signals LiFi can be used which will communicate with the LED lights of the cars and accident numbers can be decreased. Thousand and millions of street lamps can be transferred to LiFi lamps tob transfer data. In aircraft LiFi can be used for data transmission. It can be used in petroleum or chemical plants where other transmission or frequencies could be hazardous.

Advantages 

High Security



Easy To Use



Fast Data Transfer



Reliable



Harmless ness



Low Cost


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Chapter 8 Li-fi vs Wi-fi LI-FI is a term of one used to describe visible light communication technology applied to high speed wireless communication. It acquired this name due to the similarity to WI-FI, only using light instead of radio.WI-FI is great for general wireless coverage within buildings, and li-fi is ideal for high density wireless data coverage in confined area and for relieving radio interference issues, so the two technologies can be considered complimentary. TECHNOLOGY

SPEED

DATA INTENSITY

Wi-Fi – IEEE 802.11n

150 Mbps

*

Bluetooth

3 Mbps

IrDA

4 Mbps

* ***

Wireless(future) WiGig Giga-IR Li-Fi >

2 Gbps 1 Gbps 1Gbps

** *** ****

Wireless(current)

The table also contains the current wireless technologies that c an be used for transferring data between devices today, i.e. Wi-Fi, Bluetooth and IrDA. Only Wi-Fi currently offers very high data rates. The IEEE 802.11.n in most implementations provides up to 150Mbit/s (in theory the standard can go to 600Mbit/s) although in practice you receive considerably less than this. Note that one out of three of these is an optical technology.

Fig 8.1 Lifi vs Wifi


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Chapter 9

CONCLUSION The possibilities are numerous and can be explored further. If his technology can be put into practical use, every bulb can be used something like a Wi-Fi hotspot to transmit wireless data and we will proceed toward the cleaner, greener, safer and brighter future. The concept of Li-Fi is currently attracting a great deal of interest, not least because it may offer a genuine and very efficient alternative to radio-based wireless. As a growing number of people and their many devices access wireless internet, the airwaves are becoming increasingly logged, making it more and more difficult to get a reliable, high-speed signal. This may solve issues such as the shortage of radio -frequency bandwidth and also allow internet where traditional radio based wireless isn‘t allowed such as aircraft or hospitals. One of the shortcomings however is that it only work in direct line of sight.

References 1:- http://timesofindia.indiatimes.com/home/science/Now-just-light-a-bulb-to-switch-on-your broadband/articleshow/9713554.cms 2:- http://oledcomm.com/lifi.html 3:- http://en.wikipedia.org/wiki/Li-Fi


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