LiFi is a revolutionary new technology capable of transmitting high volumes of data through the modulation of visible light. It is a form of visible light communication technology that is capable of transmitting data in two directions. As such, to define its history, we must also define the history of VLC technology.
Visible Light Communications
Visible Light Communications (VLC) technology uses visible light for the transmission of data. Although it may be considered a relatively new form of technology, it can actually be traced back to the time of Alexander Graham Bell and his invention, the photophone.
On February 19, 1880, Alexander Graham Bell and his assistant Charles Sumner Tainter jointly invented the photophone. The photophone was a device that wirelessly transmitted speech using a beam of light.
The photophone’s design was modeled after the contemporary phone at the time – except that it used modulated light instead of modulated electrical signals. The sound was projected toward a mirror through a sound-receiving device. The resulting sound waves caused similar vibrations on the mirror. Sunlight was directed into the vibrating mirror and was projected back to the receiver, which was converted back to sound.
Bell considered the photophone as one of his most important inventions. It was revolutionary as it was the first to utilize modulated light for communication. It also served as a precursor to various optical communications technologies including fiber optics and VLC.
The earliest known work on modern VLC began at Nakagawa Laboratories in Keio University, Japan. Research on the technology focused on transmitting data by visible light through the use of light emitting diodes (LEDs).
Japanese researchers proposed the concept of communication through visible light in 2000. Using LED lights as a base station, the researchers simulated an indoor communication system that would utilize overhead lighting as a medium of transmission.
The researchers at Nakagawa saw the prospects brought by VLC technology. They placed plenty of effort into their research into the technology and in 2009, were able to create a high-speed communication technology that reached 100 Mbit/s.
VLC Developments in the USA and Europe
In 2006, CICTR researchers at Pennsylvania State University suggested the combination of power-line transmission and LED technology for efficient broadband access. Through this channel, home networking becomes available while also providing low-cost, efficient lighting.
The European Union (EU), in 2008, launched their own research project into VLC called OMEGA. The project aimed to develop an ultra-high-speed home access network capable of speeds up to 1 Gbit/s. The theoretical test network speed was 1.25 Gbit/s. They were able to reach a transmission speed of 300 Mbit/s.
In the same year, the US National Science Foundation performed various projects focused on Smart Lighting Communications (SLC) aimed at improving wireless communication technology. The initiative provided research grants to Boston University, Rensselaer Polytechnic Institute, and the University of New Mexico. Grantees were tasked to develop communication technology through the use of LED bulbs as a WiFi access point equivalent.
Numerous research projects were conducted within the EU and the US, including several conducted within the University of Edinburgh in Scotland that led to the invention of LiFi.
Invention of LiFi
VLC is an umbrella term that encompasses all communications technologies that use visible light. LiFi makes use of the basic principles of VLC yet uses a two-way network protocol to provide high-speed network connectivity. Much of the research into LiFi was conducted by a team of researchers at the University of Edinburgh, spearheaded by Prof. Harald Haas.
Professor Harald Haas and LiFi
Professor Harald Haas and his team of researchers are pioneers in the field of LiFi. They began their research into VLC technology as early as 2006. Much of their research ventured into the use of light as a medium for two-way transmission of data, which paved the way for LiFi technology.
Although it wasn’t the exact moment it was invented, the term LiFi was introduced to the world in 2011 during his TED Talk. The talk was entitled Wireless Data from Every Lightbulb. It was at the talk where he coined the term Light Fidelity (LiFi), a play on the term Wireless Fidelity (WiFi). To demonstrate the capabilities of the new technology, Prof. Haas provided a live demonstration by streaming a large, high-definition video from a standard LED lamp.
Prof. Haas helped start a company that would market LiFi technology in 2012. The company was named pureVLC, but was later renamed pureLiFi, and was an original equipment manufacturer (OEM) that was set to commercialize LiFi products and push for their integration with existing LED-lighting systems.
Through the years, pureLiFi was able to produce a variety of LiFi products designed for easy integration of LiFi into existing devices.
The LiFi Consortium
In 2011, four industry leaders from four different countries created a group that seeks to enhance and promote different Optical Wireless Communication (OWC) technologies. The group was known as the LiFi Consortium. It was founded by Fraunhofer IPMS, Germany, IBSENtelecom, Norway, Supreme Architecture, Israel/USA, and TriLumina, USA.
The focus of the consortium is not limited to LiFi, however, as previously stated. Instead, it pushes for the advancement of all forms of OWC, which include LiFi and fiber optics, among others.
Advances in LiFi technology were on display over the years. In August 2013, LiFi systems were able to demonstrate data rates of over 1.6 Gbit/s over a single color LED.
One of the biggest concerns about using LiFi for wireless communication is that it would require a line of sight to gain a signal. Those concerns were assuaged, thankfully, as it was announced in 2013 that LiFi systems will not require line-of-sight conditions.
In October 2013, Chinese manufacturers were working on LiFi development kits. The scientists say data speeds of up to 150 Mbps were possible through the use of microchipped bulbs. Chi Nan, the lead scientist on the team, acknowledges that LiFi’s success as a commercial technology will rely on the development of key pieces of technology. These will include light communication controls and microchip design and manufacturing.
In April 2014, Russian company Stins Coman announced their development of BeamCaster, a LiFi wireless local network capable of transferring 1.25 gigabits of data per second. They foresee boosting speeds of up to 5 Gb/s in the near future.