LiFi - Using Ordinary Light as a Source of WiFi?

Li-Fi, standing for "Light Fidelity," essentially  uses visible light systems and sources to communicate data wirelessly at phenomenal speeds.

To understand Li-Fi and appreciate it, we must first know the basics about Wi-Fi.  Wi-Fi is wireless connectivity, allowing your devices to connect at high speed to the internet without any need for physical wires (unlike Ethernet which converts data to electrical signals and travels via a wire), whereas using wireless connectivity, data is carried by radio waves.  Wi-Fi signals are transmitted at two specific frequencies, 2.4GHz and 5.0 GHz which allow for a constant communication between your router and device. How do radio waves carry such complex variants of information across the air and into our devices? Well, the data that is being communicated from our device is broken down into binary data, i.e. a complex thought or process is broken down into only the numbers 0 (false) and 1 (true). Strings of these numbers code for various types of data which is patternized via amplitude modulation. Lets say we wanted to send a piece of data - it has been broken down into the code 10011 - a waveform like this would be transmitted:

Like anything, Wi-Fi has its issues. One of the most prominent being slow connection. When attempting to research further issues about Wi-Fi, I was inundated with troubleshooting websites which took my search request too literally.

In an ideal world, we would like to eliminate a majority of these troubleshoots, which is where
Li-Fi could come in.

Light and radio waves are actually the same thing. Li-Fi is the "visible spectrum range (band of frequencies) within the EM spectrum.  In this case the visible spectrum is radio waves at a much higher frequency. The definition of frequency given by Google is "the rate per second of a vibration constituting a wave, either in a material (as in sound waves), or in an electromagnetic field." So the waves would be transferring data at a much faster rate. 

The maximum frequency light can reach is 790THz, whereas for radio waves it is a mere (relative) 390 GHz, so light has the potential to transmit more data in less time.

Harald Hass, a leading pioneer in this field gave a TED talk a couple years ago showing off this idea in its infancy. He says that the infrastructure is already there (as in we already have light bulbs and other sources of light everywhere), but if we could replace them with LEDs (which is now the case as they are much more efficient), then this could very easily work. LEDs are semiconductors, so its intensity can be modified at extremely high speeds e.g. turning off and on to mimic a 0 (false // off) and 1 (true // on) binary code which can then be used to transmit data, at even higher speeds due to higher frequencies.

Speeds of 10 Gigabits [1x10^10 bits] have been achieved in lab conditions, compared to 100 Megabits using standard Wi-Fi.  [[ For reference, a bit is the smallest unit of storage i.e. a 0 or a 1. 8 bits make up a byte, which are the conventional units of storage we see in our day to day lives e.g. megabytes, gigabytes etc. ]]

This promising technology has also been recently reported by the BBC here. The key parts of the article are stated below:

"Within the ceiling, the light bulbs have been connected to access points that are wired to the internet. If you didn't know that, though, you'd simply think you had walked into a well-lit room."

"Li-Fi could extend mobile connectivity into those hard-to-reach indoor spaces. Or Li-Fi bulbs could replace streetlights in well-lit urban areas to provide high-speed connections to densely packed crowds of people."

"Hospitals could easily hook up healthcare devices to the local network without having to rely on over-burdened Wi-Fi networks or relying on potentially hazardous cables."

"For the O2 demo, a dongle was plugged into a tablet to receive the Li-Fi signal. But for the technology really to take off, these light-reading sensors would have to be built in to devices - a considerable obstacle."

"And the most obvious drawback is that your phone won't be able to pick up a signal if it's in your pocket or bag. But given how much time we spend staring at our small screens, maybe this wouldn't be such an issue."