The Existing telecommunication system relies on radio waves of the electromagnetic spectrum for data transmission. Light waves (visible part of the spectrum between 400nm to 700nm) contains ten thousand times broader spectrum than radio waves. It has a promising potential for very high data transmission, theoretically up to 10 Gbps. The basic idea is to use light waves instead of radio waves for data transmission. It was first demonstrated by the German physicist Harald Hass. He termed this technology Li-Fi. We will check feasibility and challenges in implementing Li-Fi in our daily life. Let us check out how to convert any LED bulb into very high speed Internet hotspot.
How does it work?
Transmission: The input data is fed into the lamp driver. The lamp driver encodes the data in the form of light by flickering or changing the intensity of the LED bulbs. The LED bulbs generate combinations of 1’s and 0’s, according to the input data, by switching itself on and off faster than the human eye can trace. Parallel data transmission can be done by using an array of multiple LED’s or by using red, green, blue LED’s to alter light frequency with the frequency of different data channel. High data rates can be achieved by using a high-speed LED and appropriate multiplexing techniques.
Reception: A Li-Fi dongle is required similar to Wi-Fi dongle. Such dongles have a very simpler circuit. It doesn’t require radio circuits, antennas, and complex receivers, a simple photodetector, and amplifier can do the job. The Li-Fi dongle can receive the light wave and convert it back into electrical signals suitable for devices such as a laptop. If this concept is successful, future devices may come with in-built Li-Fi receiver.
Why is it a good deal?
- The visible light spectrum is free and it does not need any license, making it economical for the industry.
- It is faster and cheaper than other forms of wireless internet.
- It can be used in electromagnetic sensitive areas such as airplanes, hospitals, petrochemical industrial plants, nuclear power plants etc.
- Very fast ON time, users need to just switch on the lights.
- Infrastructure is already available, it can be easily integrated into the existing lighting systems.
- It is safe to use, In fact, it is just the light that we use every day.
What are the challenges?
- Any obstacle stopping the light will interrupt the Li-Fi connection. Light can’t pass through the walls and hence Li-Fi is limited within the walls, this makes it feasible only for short distances. But this shortcoming is also very beneficial, no one can sneak into your device via Li-Fi from another side of the wall. This makes it a highly secure network.
- You cannot use LiFi while the lights are off unless you use only Infrared spectrum, which restricts bandwidth.
- Li-Fi needs technical improvement to deal with interference with sunlight and other sources of light.
- Li-Fi has no standard yet, so equipment from one vendor won’t work with another.