Research Team Uses Conventional Solar Cell as LiFi Receiver in Prototype

Researchers at the University of Edinburgh have developed a prototype system that combines solar power and Li-Fi. In the developing world, access to reliable power is a prohibitive obstacle to accessing Internet communication and Wi-Fi. The idea, which Edinburgh University’s Professor Harald Haas pioneered, seeks to bring solar powered Li-Fi to give Internet access to rural communities in the developing world where just getting electricity is an issue.

Wi-Fi Access requires an electric infrastructure that is not available in the developing world. The infrastructure uses transmitters that operate at only about 5% efficiency. With LiFi, light from rapidly pulsed LEDs is used to transmit data. The data is encoded in subtle changes in the brightness of the LED. LEDs have a unique property of being able to be turned on and off at very high speeds, and its brightness can be modulated at high speeds.

The remarkable demonstration was able to show how standard, off-the-shelf LED lights could be used to transmit data through subtle changes in their brightness to standard off-the-shelf solar cells. The solar cells receive subtle power fluctuations through the changing brightness of the LEDs.

In the lab, Haas and his team claim to have been able to transmit up to 50 GB per second of data through this method. Haas noted is greater bandwidth than most broadband can achieve. The specific encoding mechanism that the team created transmits thousands of data streams simultaneously. Solar panels on the prototype device can serve a dual purpose of providing electricity to power the LEDs and acting as a receiver for Li-Fi signals. The conventional LED bulbs can continue to be used to light a room. The subtle changes in brightness are not visible to humans. The data transmission is completely secure. It does not go through walls.

Professor Harald Haas lead a research team at the University of Edinburgh’s Li-Fi R&D Center that developed the solar-powered Li-Fi prototype in partnership with pureLiFi Ltd, a University of Edinburgh spin-out company. pureLiFi Ltd is widely acknowledged as the corporate pioneers of using the visible light spectrum instead of radio frequencies to enable wireless data communication.

At this year’s TED Global event in London, professor Haas demonstrated how Li-Fi can be used with solar cells to receive data. At the TED talk, Haas explained the potential of using solar panels on houses and future mobile devices to both absorb power and access the Internet and also play a role in spreading the Internet of Things for all kinds of smart electronic appliances.

Edinburgh Research & Innovation (ERI), the commercialization branch of the University of Edinburgh, is now seeking industrial partners to collaborate with the University’s Li-Fi R&D Centre in developing the technology for commercial use.

Tom Higgison, ERI’s IP projects manager, commented,
“This University of Edinburgh technology combines light-based data communications, or ‘Li-Fi’, with energy harvesting, to create an exciting set of applications not previously anticipated including in rural broadband access, smart city networks, and the internet of things. The wider opportunity is to transform global communications by speeding up the process of bringing internet and other data communication functionality to remote and poorer regions in a way not previously thought achievable due to lack of infrastructure and investment.”
During his presentation, Professor Haas explained that more than four billion people around the world do not have access to the internet, and the developing world has little energy infrastructure to support traditional broadband and Wi-Fi. Therefore, Haas asserts that solar energy and LEDs can help overcome the data divide.
Professor Haas said,
“The potential expansion to the internet is massive, and my aspiration is that this broadband solar panel receiver technology for Li-Fi will help solve the challenges of the digital divide throughout the world, and catalyse the uptake of the IoT as connectivity and battery-free power supplies are essential if we want to connect a trillion objects to the internet.”

In conventional optical wireless communications, the steady background component of an optical signal is usually discarded, but Haas says it can instead be used to directly power to the receiving terminal.

Professor Haas delivered a recent TED Talk on this technology. The video of his TED talk is available at:

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