Li-Fi stands for Light-Fidelity. The technology is very new and was proposed by a German physicist Harald Haas in 2011. Li-Fi provides transmission of data through illumination by sending data through an LED light bulb that varies in intensity faster than human eye can follow. I'll discuss the technology in detail and also how Wi-Fi can be replaced by Li-Fi. Wi-Fi is useful for general wireless coverage within buildings while Li-Fi is ideal for high density wireless data coverage in confined areas where there are no obstacles. Li-Fi is a wireless optical networking technology that uses light emitting diodes (LEDs) for transmission of data. The term Li-Fi refers to visible light communication (VLC) technology that uses as medium to deliver high-speed communication in a manner similar to Wi-Fi.
Li-Fi provides better bandwidth, efficiency, availability and security than Wi-Fi and has already achieved high speeds in the lab. In this article i'll share everything about Li-Fi, its advantages and its future scope.
In an experiment, Professor Haas used a table lamp with an LED bulb to transmit a video of a blooming flower that was then projected onto a screen. During his TED talk, he periodically blocked the light from the lamp with his hand to show that the lamp was indeed the source of the video data. Li-Fi can be regarded as light-based Wi-Fi, i.e. instead of radio waves it uses light to transmit data. In place of Wi-Fi modems, Li-Fi would use transceivers fitted with LED lamps that could light a room as well as transmit and receive information. It makes use of the visible portion of the electromagnetic spectrum which is underutilized. Li-Fi can be considered better than Wi-Fi because there are some limitations in Wi-Fi. Wi-Fi uses 2.4 – 5 GHz radio frequencies to deliver wireless internet access and its bandwidth is limited to 50-100 Mbps. With the increase in the number of Wi-Fi hotspots and volume of Wi-Fi traffic, the reliability of signals is bound to suffer. Security and speed are also important concerns. Wi-Fi communication is vulnerable to hackers as it penetrates easily through walls.
Problems with Wi-Fi which we need to overcomeEfficiency: There are 1.4 million cellular radio masts worldwide. These masts consume massive amounts of energy, most of which is used for cooling the station rather than transmission of radio waves. In fact, the efficiency of such stations is only 5%
Availability: Radio waves cannot be used in all environments, particularly in airplanes, chemical and power plants and in hospitals.
Security: Radio waves can penetrate through walls. This leads to many security concerns as they can be easily intercepted.
Capacity: The visible light spectrum is 10,000 times wider than the spectrum of radio waves. Additionally, the light sources are already installed. Hence Li-Fi has greater bandwidth and equipment which is already available.
Efficiency: LED lights consume less energy and are highly efficient. Availability: Light sources are present in all corners of the world. Hence, availability is not an issue. The billions of light bulbs worldwide need only be replaced by LEDs.
Security: Light of course does not penetrate through walls and thus data transmission using light waves is more secure.
The applications of Li-Fi are derived from many of these benefits and will be studied in detail in later sections.
Frank Deicke, who leads Li-Fi development at Fraunhofer Institute for Photonic Microsystems in Germany, has said that Li-Fi can achieve the same data rates as USB cables which is challenging for wireless technologies such as Bluetooth and Wi-Fi. He also cites another advantage of Li-Fi being that the latency of Li-Fi is in the order of microseconds where as that of Wi-Fi is in the order of milliseconds.
With the above benefits encouraging us to adopt this new technology, the actual need for Li-Fi can be confirmed from Cisco’s Visual Network Index which suggests that user demand is increasing faster than gains in spectral efficiency. By 2020, traffic from wireless devices is expected to exceed that from wired devices. Such increases in network traffic require significant changes in how we think of wireless communication and Li-Fi may be the change that we need.
Reason why Light is better than Radio-Frequency for wireless data transmissionThe reason why data transmission by light is faster is the wavelength of light:
As you can see in this spectrum, visible light has lower wavelength and high frequency (10^15) which makes it about 10^7 times faster than FM waves (10^8) to transfer data.
General working principle of LiFiLight emitting diodes (LEDs) can be switched on and off faster than the human eye can detect since the operating speed of LEDs is less than 1 μs, thereby causing the light source to appear to be continuously on. This invisible on-off activity enables data transmission using binary codes. Switching on an LED is binary ‘1’, switching it off is binary ‘0’. It is possible to encode data in light by varying the rate at which LEDs flicker on and off to give different strings of 1s and 0s. Modulation is so rapid that humans cannot notice it. A light sensitive device (photo detector) then receives the signal and converts it back into original data.
This method of using rapid pulses of light to transmit information wirelessly is technically referred to as Visible Light Communication (VLC).The term Li-Fi has been inspired due to its potential to compete with conventional Wi-Fi. The VLC uses visible light between 400 THz (780 nm) and 800 THz (375 nm) as the optical carrier for data transmission and for illumination. Data rates of greater than 100 Mbps can be achieved by using high speed LEDs with adequate multiplexing. Parallel data transmission using arrays of LEDs where each LED transmits a separate stream of data can be used to increase the VLC data rate. Though the lights have to be kept on in order to transmit data, they can be dimmed to the point that they are not visible to humans but still be capable of transmitting data.
Setup basically has 2 components, the LED bulb (1) and a photo detector (2) to analyse signals.
How can CbyGE bulbs disrupt the market using this technology?CbyGE can be used in various places. Here are the applications below:
The possibilities of CbyGE are endless because it has tons of applications.
Design for the bulbThis is the design for the bulb which I ideated.
The bulb will consist of a PCB which you modulate data to be sent over the bright LED's connected. It would have a Ethernet cable slot so that cable can be plugged into it for data transmission.
ConclusionI would like to conclude that Li-Fi has the potential to change the way how people access the internet.
Today there are tons of companies which make smart light bulbs, but none of them offer facilities like data transmission. With this idea, GE would be able to offer great value to its customers who are fond of smart bulbs and hence it would become a leader in the smart lighting industry in the future.
Smart lighting market size expected to rise by $8.14 Billion, and Li-Fi by $75 Billion by 2020 which makes Li-Fi the next big opportunity.
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