Visible Light Communication

Visible light communication (VLC) is a wireless method that uses light emitted by LEDs to deliver networked, mobile, high-speed communication similar to Wi-Fi, leading to the term Li-Fi. It can be used as standalone solution or in a supplementary role to radio-frequency (RF) or cellular network communication.

The basis of the technology, conceived by Professor Harald Haas of the University of Edinburgh, involves switching LEDs ON and OFF within nanoseconds at a very high frequency. Haas demonstrated the technology at a TED Global talk in 2011 and went on to co-found PureLiFi, a Li-Fi technology OEM for LED manufacturers.

As the visible light spectrum is 10,000 times larger than the radio frequency spectrum, VLC is regarded as a solution to RF bandwidth limitations. Industry has generated very high data transmission rates, making it competitive.

Though the signal cannot penetrate obstructions such as walls, a direct line of sight is not required as long as long as light is reflected from other surfaces. The LED lighting must be ON for the signal to transmit but can be dimmed to very low levels. VLC has an advantage over Wi-Fi in that transmission does not cause electromagnetic interference.

Applications are broad, but one application has attracted key interest by major lighting manufacturers Acuity Brands, GE and Philips. That is to say, big box retail.

Lighting has long been considered the “silent salesperson” in retail because it facilitates wayfinding and can be used to attract shoppers to key merchandise. VLC introduces a new way to connect retailers and their customers to enhance the shopping experience and improve value.

According to Deloitte Consulting LLP, in 2012, more than 60% of mobile shoppers used smart phones while in the store, and 85% of consumers were using retailers’ native apps or websites during shopping trips. In the solutions being demonstrated by Acuity, GE and Philips, the LED luminaires provide a communication point with shoppers using mobile phones (or camera-enabled tablets) loaded with an app, appealing to a ready market. With VLC, the store’s luminaires communicate with shoppers in two primary ways.

First, VLC provides indoor GPS-like location-positioning functionality that enables wayfinding. Shoppers looking for particular items in their shopping list can be guided straight to them. Second, the owner can deliver targeted information to its customers. As a shopper passes a product section in an aisle, for example, their phone can receive coupons, recipes and other information.

Philips’ “connected lighting system,” demonstrated earlier this year at EuroShop and LIGHTFAIR, consists of LED luminaires in a dense network that provides illumination while also functioning as a positioning grid. Each luminaire is identifiable and able to communicate its position to an app on a shopper’s smart device.

“The beauty of the system is that retailers do not have to invest in additional infrastructure to house, power and support location beacons for indoor positioning,” says Gerben van der Lugt of Philips. “The light fixtures themselves can communicate this information by virtue of their presence everywhere in the store.”

GE partnered with ByteLight to demonstrate “LED infrastructure” that will be available in the next generation of GE LED luminaires. The technology uses a combination of VLC and Bluetooth for communication. The lighting can communicate with smart phones and tablets with a camera.

“GE Lighting’s next generation of LEDs not only will save energy and maintenance costs, they will be a strategic enabler to combining big data with location to deliver a more engaging shopping experience that increases customer loyalty and value,” says Jaime Irick, general manager of North America Professional Solutions, GE Lighting.

Acuity Brands partnered with Qualcomm Technologies to develop a solution based on its eldoLED driver platform. Lumicast determines a mobile user’s location within 10 centimeters, as well as the user’s orientation within the aisle. Like GE and Philips, Acuity is currently engaging top retailers to conduct proof of concept testing.

“This new technology allows LED lighting to be an asset for retailers, not only because of the productivity gains, energy savings and environment improvements it provides, but also because of its emerging capacity for enhancing and changing in-store customer experiences,” says Steve Lydecker, senior vice president for Acuity Brands Lighting. “Guiding the shopper through the store based on the shopper’s actual position, visible light communication technology opens the door for retailers to more effectively engage and influence consumers on the retail floor.”

VLC is an exciting development and represents a potential shift in the chief value conversation about retail lighting from light/dollar to how the lighting system can more directly support sales. Based on VLC’s success in big box, more commercial building applications will likely follow. There is also strong potential to incorporate other devices within the LED luminaires, such as sensors, that can be used to capture traffic and buying activity throughout the store, providing valuable analytics for retailers.