As LED becomes a more common source for room lighting, they’re opening a new pathway for linking mobile devices to the Internet, with the potential for wider bandwidth and quicker response time than Wi-Fi. Li-Fi encodes data on the light coming from LEDs by modulating their output. The rapid flickering is unnoticeable to the human eye, but a receiver on a desktop computer or mobile device can read the signal, and even send one back to a transceiver on the ceiling of a room, providing two-way communication. But many LEDs use a phosphor coating to convert blue light to white, and that limits how fast the devices can be modulated, holding down data rates. Li-Fi signals are confined to narrowly-focused beams that don’t travel through walls. Moreover, LED lights are natural beam formers, which makes it easier to create separate uplink and downlink channels, which essentially means more secure internet browsing, given that both channels have to be intercepted if someone did manage to coerce their way into the same room as you. the Li -1st allows you to network via desktop photosensitive unit that works in tandem with an off-the –shelf, unmodified light fixture.
The desktop unit has infrared LED to communicate in the uplink channel. We were given a demo by Haas in his light emporium. But Haas says that this version is limited by existing LEDs, and by the use of LEDs as transmitters and detectors at the same time. Members of the consortium, however, have created a better LED, which provides a data rate close to 4 gigabits per second operating on just 5 mill watts of optical output power and using high-bandwidth photodiodes at the receiver. With a simple lens to enhance the distance, they can send data 10 meters at up to 1.1 GB/s, and soon they will increase that to 15 GB/s, Haas says. The 802.11ad Wi-Fi standard for the 60-gigahertz radio band reaches just under 7 GB/s, so Li-Fi would more than double that rate.
You can have more or less the same data rate as over a USB cable,” Deicke says. “That’s very challenging for most wireless technologies, like Wi-Fi and Bluetooth.” Another advantage, says Deicke, is that the latency of Wi-Fi—the time between when a signal is sent and when it’s received—is measured in milliseconds, whereas Li-Fi’ latency is on the order of microseconds. In industrial applications, where data has to flow between sensors, actuators, and a control unit, low latency and high data rates would make Li-Fi useful in places where Wi-Fi is not. See more scenarios to get detailed information about visible light communications and how they are read to compete with Wi-Fi.