High-speed bi-directional wireless technology that uses light to send information securely offers faster, safer transfer of data than conventional wi-fi. In addition, because it does not rely on the radio spectrum, it provides 10,000 times more bandwidth — the fundamental resource of all communication systems. Light-enabled wi-fi, or Li-Fi, was first developed by Professor Harald Haas, Chair of Mobile Communication with the University of Edinburgh. Haas is co-founder of the spin-out company pureLiFi.

As increasing amounts of Internet data are transmitted through mobile networks, the current radio spectrum could run out of capacity in the next five years. This looming spectrum crunch could severely limit people’s ability to access information, potentially costing the world’s economy billions of dollars.
 
Haas said: “The UK industry regulator for communications, Ofcom, has warned that the available radio spectrum will run out by 2020. By that time, it is forecast that there will be a staggering 7 trillion wireless devices in use. This means, for every person on the planet, there will 1000 wireless devices; so, a solution is needed.”
 
Li-Fi creates the possibility of everyday objects housing LED lights to also transmit data. In many cases, vehicles, household appliances, even jewelry already have LEDs within them. The technology offers opportunities across sectors, including mobile communications, energy, healthcare, transport, manufacturing, lighting, security and advertising. The industry is estimated to be worth at least $6 billion in the next five years.
 
In healthcare, micro LEDs integrated into an earring, for example, could monitor temperature, blood pressure or sugar levels and transmit the data to a mobile phone or a doctor’s surgery. In hazardous environments where radio signals are not permitted, such as offshore oil and gas platforms, using light waves to send data wirelessly could save the industry hundreds of millions of dollars a year in maintenance cost and could greatly enhance safety.
 
Self-driving cars could use their lights to communicate with each other to enhance road safety, and intelligent traffic lights could transmit local congestion data; billions of smart household appliances from TVs to toasters could gather data and save energy through Internet-enabled light sources — Li-Fi can be instrumental in realizing the future ‘Internet-of-Things.’
 
Haas explains that Li-Fi offers greater security compared with wi-fi: “Light waves do not pass through walls, so secure wireless communication is possible in cyber-secure spaces. Moreover, there are areas where radio simply does not work, or is not permitted, such as underwater and in aircraft cabins. The possibilities are nearly unlimited.”
 
Li-Fi technology also gives much higher transmission speeds and capacity. By utilizing a LED light bulb, data can travel at over 10 gigabits per second, and with tens of light bulbs in an office or factory space, there would be hundreds of gigabits per second available.
 
With conventional wi-fi, the same room can only have a single wi-fi access point, as the radio signals from additional access points interfere with each other, compromising transmission capacity. The latest wi-fi technology, WiGig, can transmit up to 7 gigabits per second. However, in a Li-Fi enabled room, the total capacity could be increased significantly.  
 
The development of white LED bulbs — essential for Li-Fi — followed the invention of blue LEDs, the importance of which was recognized earlier this month by the award of the Nobel Prize for Physics 2014 to three Japanese researchers for their work in this field.
 
The University of Edinburgh has set up the Li-Fi Research & Development Centre to lead the technology’s global development. Partners already include Texas-based National Instruments.