Each day we use Wi-Fi and Bluetooth to communicate and send data. This wireless technology has revolutionized the way we use mobile phones and tablets, making the internet accessible from almost anywhere. However, carrying data via radio frequencies is becoming increasingly crowded and the technology is flawed. Using radio waves to communicate offers a decent speed but transmits slowly and the signal can be blocked or affected by other equipment, such as the microwave in the kitchen.
Scientists have been working on a new, extremely fast alternative called Li-Fi, which was first introduced by Harald Haas from the University of Edinburg in 2011. Li-Fi, short for light fidelity, uses pulsing light from a special LED as a medium to deliver secure, networked, mobile, high speed communications, transmitting data in a more effective and secure way than traditional radio-based communication technology.
Light might seem an unusual choice, but in fact it is already a very popular means of sending data over long distances; fiber optics send information via tiny strands of silicon and make up the arteries of much of our modern internet.
Li-Fi works in a very similar way to Wi-Fi, but instead of spewing out radio waves in all directions to allow a device to connect to the internet, Li-Fi employs LED lights flickering – 1 for on, 0 for off - at high speeds to spread light around a room to allow all devices to connect. The light is switched on and off incredibly quickly to transmit data which can be encoded by the light flickering at different rates to give a different string of 1s and 0s. The LED intensity is modulated so the human eye can not detect the flickering and the output appears constant.
Li-Fi is expected to have many uses and it offers several advantages over Wi-Fi, including the ability to operate over higher bandwidths including the visible light spectrum, ultraviolet and infra-red. It is also much faster; while Wi-Fi can reach speeds of up to 867 megabits per second, Li-Fi has the potential to reach 10.5 gigabits per second.
Li-Fi is also more secure than Wi-Fi. It only works when a device can detect light being emitted by a Li-Fi router, so in the same room or area that the light us being emitted from. Since the signal can’t be hacked from a remote location, because light can’t penetrate walls, it will be easier to control access to networks – meaning people can no longer piggyback off your connection - and access to a Li-Fi channel will be limited to devices inside the room.
Li-Fi also has the added benefit of being able to function in areas susceptible to electromagnetic interference, such as aircraft cabins and hospitals. It offers a more secure means of transmitting information about patients and has the added benefit of having little to no effect on medical instruments and the human body.
Other uses could be found in remotely operated underwater vehicles which are currently controlled by wired connections, thus limiting their operational range. Since light travels through water, Li-Fi-based communication could offer increased mobility, but it is still limited by light’s ability to penetrate water at around 200m.
Vehicles such as cars and buses could use their front and back lights to communicate with each other to improve road safety, while street lights and traffic signals could also employ the technology to provide updates on current road conditions.
It is also expected that all future home and building automation will be dependent upon the technology, thanks to its fast and secure nature. Li-Fi could also help with industrial automation by replacing industrial ethernet and providing an alternative to common industrial wireless LAN standards.
Li-Fi has the potential to revolutionize wireless communications and benefits from the existing lighting infrastructure, meaning little investment is needed, but we are still a long way off seeing it in our homes.
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