LI-FI (LIGHT FIDELITY) THE FUTURE TECHNOLOGY IN WIRELESS COMMUNICATION 1
Presented by:- Jinal K. Dhobi M.E.(E.C)
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PRESENT SCENARIO IN WIRELESS COMMUNICATION Wi-Fi – IEEE 802.11n
Speed up to 150mbps Bluetooth
Speed up to 3mbps IrDA
Speed up to 4mbps
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ISSUES WITH WI-FI USING RADIO WAVES
Capacity
Several Ten’s of Mbps
Efficiency
Maximum 1.2((bits/s)/Hz per site)
Health Issues & Security
Radio Waves Injurious To Health The Radio Wave Penetrate Through The Walls
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ALTERNATIVES TO RADIO WAVES IN EM SPECTRUM
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WHO CAN REPLACE RADIO WAVES FOR WIRELESS COMMUNICATION ?
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LI-FI
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INTRODUCTION OF LI-FI
Li-Fi is a VLC, visible light communication, technology developed by a team of scientists including Dr Gordon Povey, Prof. Harald Haas and Dr. Mustafa Afgani at the University of Edinburgh.
Li-Fi is now part of the Visible Light Communications (VLC) PAN IEEE 802.15.7 standard.“Li-Fi is typically implemented using white LED light bulbs.
Li-Fi can be thought of as a light-based Wi-Fi. That is, it uses light instead of radio waves to transmit information. And instead of Wi-Fi modems, Li-Fi would use transreceiver-fitted LED lamps.
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CONSTRUCTION OF LI-FI
Power supply
Light sources
Photo detector
Signal processing unit or controller
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HOW LI-FI WORKS? Its working is much simply explained as follows:
If the LED is on, The digital 1 is transmitted
And if it is off, The digital 0 is transmitted
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.
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Continue…..
Further enhancements can be made in this method, like using 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 advancement promise a theoretical speed of 10Gbps – meaning you can download full high-definition film in just 30seconds.
This method of using rapid pulses of light to transmit information wirelessly is technically referred to as visible light communication and it can compete conventional Wi-Fi.
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EFFICIENCY
Blazing fast data rate and depleting bandwidth worldwide are not the only reason that give this technology an upper band
Since LI-FI uses just the light, it can be used safely in aircraft 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 operation.
Light is inherently safe and can be used in place where radio frequency communication is often deemed problematic, Such as in aircraft cabins or hospitals.
The visible light spectrum is unused, it’s not regulated, and can be used for communication at very high speeds.
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LI-FI ENVIRONMENT
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BENEFITS OF LIGHT WAVES
CAPACITY
Light is a readily available form of energy and it covers the major portion of the EM Spectrum. Visible light Spectrum is 10000times more compared to radio waves spectrum.
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AVAILABILTY
Light is readily available in every part of the world these makes it easy for people in airplanes to work on the internet. there are an estimated 14billion light sources on the earth and each can be easily converted into a LI-FI hotspot
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SECURITY
Unlike Radio Waves, light Waves can not penetrate through out opaque objects thus providing plenty of network privacy. No other person can share a network unless the owner has permitted them to use it. The sources can be used as normal lights when there is no use for a hotspot.
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ECONOMIC
The tariff rates can be very cheap as light waves are a cheap resource. There can be transparency in spectrum allocations due to it’s cheapness.
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ADVANTAGES
SUPERIORITY OVER RF WAVES
The visible light has considerable edge over RF waves in many fields.
LITTLE INFRASTRUCTURE REQUIREMENTS
There are an estimated 14 billion bulbs in the world today. Since Li-Fi can operate on conventional LEDs infrastructure is pretty much present already .
SIMPLE SYSTEM STRUCTURE
A typical Li-Fi system consists of an LED array, a photoreciever , a de/modulator pair.
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DISADVANTAGES
The biggest disadvantage is that it needs direct line of sight to transmit data, so one wouldn't be able to have a single router in his/her house and the data does not goes through walls etc..
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APPLICATIONS OF LI-FI SMART LIGHTING
Any private or public lighting including street lamps can be used to provide Li-Fi INDOOR POSITIONING
Transmission of a unique ID is all that is required for basic positioning. Multiple LED light bulbs can be used with trilateration for more accurate indoor positioning and navigation.
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MOBILE CONNECTIVITY
Laptops, smart phones, tablets and other mobile devices can interconnect directly using VLC. Short range links give very high data rates and also provides security via the visible pairing method. HAZARDOUS ENVIRONMENTS
VLC provides a safe alternative to electromagnetic interference from RF communications in environments such as mines and petrochemical plants.
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VEHICLES & TRANSPORTATION
LED headlights and tail-lights are being introduced. Street lamps, signage and traffic signals are also moving to LED. This can be used for vehicle-to-vehicle and vehicle-to-roadside communications. This can be applied for road safety and traffic management. HOSPITAL & HEALTHCARE
VLC emits no electromagnetic interference and so does not interfere with medical instruments, nor is it interfered with by MRI scanners.
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UNDERWATER COMMUNICATIONS
Due to strong signal absorption in water, RF use is impractical. Acoustic waves have extremely low bandwidth and disturb marine life. VLC provides a solution for short-range communications. RF AVOIDANCE
Some people claim they are hypersensitive to radio frequencies and are looking for an alternative. VLC is a good solution to this problem.
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THE FUTURE IS VERY BRIGHT In the next decade this technology can be made available every where. Places where optical fiber are difficult to reached using this technology. Every light sources on earth can be hotspot making technology very much available to every person on earth.
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CONCLUSION
The possibilities are numerous can be explode further. If this technology can be put into practical use, every light sources can be used something like a Wi-Fi hotspot to transmit wireless data end 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 clogged, 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 hospital. One of the shortcomings however is that it only work in direct line of sight.
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REFERENCES [1] Megha Goyal, Dimple Saproo, Asha Bhagashra, “New Epoch of Wireless Communication: Light Fidelity,” International Journal of Innovative Research in Computer and Communication Engineering Vol. 1, Issue 2, April 2013 [2] Jyoti Rani, Prerna Chauhan, Ritika Tripathi “Li-Fi (Light Fidelity)The future technology In Wireless communication,” International Journal of Applied Engineering Research, ISSN 0973-4562 Vol.7 No.11 (2012). [3] http://en.wikipedia.org/wiki/Li-Fi. [4] http://www.lificonsortium.org [5] seminarprojects.com/s/seminar-report-o-Li-Fi. [6] http://blog.ted.com/
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