Tag Archives: communication

Say Hi to Li Fi

Abhishek K

How would you feel if somebody tells you that Wi-Fi is going to get a hundred times faster? You are ready to welcome Li-Fi. Li-Fi is coming to the markets soon at the speed of Light.

Li-Fi is successor of the Wi-Fi technology. While Wi-Fi uses radio waves to transfer data, Li-Fi uses visible light. In Li-Fi, there is no radio router, but an LED light emitter. This technology was conceived by Professor Harald Hass who started researching on it back in 2003 as saw the upcoming spectrum crunch. He correctly predicted that the lack of radio frequency spectrum for mobile devices would become a real problem. Around the same time, new LED light technology hit the market, and Hass saw an opportunity to bring the two together. He found a way to use these electronic lighting components for high speed data communication, without interfering with existing radio frequency infrastructures.

His Li-Fi setup consists of brick-sized boxes attached to LED lamps and they are called as LED downlighters, which when illuminated cover an area of around 20 square meters. The boxes effectively turn the lights into wireless antennas; antennas which emit visible light. Very high speed fluctuation in emitted light is what transfers data. To receive data from these lights you need a dongle that acts as a wireless modem of sorts, which is plugged into your laptop or tablet. The dongles are a bit smaller than a pack of cards and plug in via USB, which also provides the power. There’ s a sensor that catches the light coming down and then an infrared component that sends a signal back up. The overhead lights also have a networking component, so it’ s possible for multiple users to connect to a single light source, and to move from one light source to another without losing your connection.

The speed of that system is 40Mbps, both downloading from the light and uploading from the dongle. The light has a 60-degree field of view which provides a coverage area of 9 to 10 square meters. The maximum data rate reduces slightly if you move to the edges of the light, dropping to around 75 percent, but the light can bounce off objects and still deliver a signal, it’ll just be slower the further you are from the main beam.

The more Li-Fi enabled lights you have in an area, the higher your total capacity is. Light also doesn’t penetrate through walls the same way Wi-Fi does, so it allows you to create networks with much higher security. Wi-Fi uses radio frequency waves, a technology which has limited space and is quickly reaching its capacity. The limited capacity is why the radio frequency spectrum is heavily regulated all over the world. One of the most endearing facets of Li-Fi is that it uses the visible light spectrum. The visible light spectrum is 10 000 times larger than the radio frequency spectrum and is unregulated. So you don’t need a license to take advantage of the light spectrum. Internet speed of 10gbps is no more a dream as far as Li-Fi is concerned although it can’t guarantee any increase in internet speed through our regular optic fibre cables.

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