Visible light communication (VLC) is a particularly exciting technology in an industry that is already going through exciting technological change. This technology, popularly used in applications such as fiber-optics, now shows promise for general lighting due to the advent of LED lighting.
The potential is to create spaces that actively communicate with users.
What is VLC?
VLC is a free-space optical wireless communication technology that uses visible light to transmit data across distances.
The concept is simple. Varying the intensity of a beam of light can be used to encode information. So simple that humans have been using optical communication since at least the time of the ancient Greeks. You can try this at home by simply turning a flashlight ON and OFF to send Morse code.
Light travels 186,000 miles per second, so communication across long distances is virtually instantaneous.
In the modern era, technological advances allowed us to modulate the light at higher frequencies, allowing richer information. Light can be transmitted across a free space (e.g., lasers communicating between two buildings) or across a medium (e.g., fiber optics).
With the advent of LED, a new idea in VLC is to use general lighting to communicate with users in a space as a replacement or supplement to Wi-Fi. While traditional light sources present practical limitations, LED lighting can be modulated at very high frequencies, with a cycle as short as nanoseconds.
This concept, called Li-Fi, could be a solution to RF bandwidth limitations as the visible light spectrum is 10,000 larger than the radio spectrum.
As a bonus, VLC doesn’t cause electromagnetic interference. The light can transmit information either directly or reflected from a surface. It can do so while dimmed. However, light cannot penetrate obstacles such as walls.
This ambitious concept is still being developed. Meanwhile, manufacturers have moved to develop VLC for specific building applications, and these solutions, now being demonstrated, will be commercially available soon.
These manufacturers are focusing on two extraordinary capabilities of luminaires that both illuminate and communicate with light. The first is using LED lighting as a network for indoor positioning. The second is targeted communication with mobile devices. While there are numerous potential applications, the initial focus is retail stores.
Seven out of 10 Americans have a smart phone or tablet, according to Opus Research. Today’s smart phones and tablets feature navigation through use of Global Positioning System (GPS) satellite signals. These signals bounce around inside buildings, however, making indoor GPS positioning ineffective.
A number of approaches can be used to achieve indoor positioning, of which VLC is now a contender. A building owner installs VLC-enabled LED general lighting. The luminaires are overlaid onto a digitized map of the space. In a retail store, this would include showing the store layout and merchandise locations.
The user downloads a loyalty app to their mobile device. The app enables positioning and provides user access to the digitized map.
When producing light, the luminaires emit their unique codes, which are read by the mobile device’s camera.
By combining the two, the system calculates exactly where on the map the person is as well as their physical orientation. Accuracy ranges from less than four inches to less than four feet.
The benefit is wayfinding. In a store, a user could determine where they are and locate areas and merchandise within a store, which may be referenced via an app-based shopping list. In a mall or airport, a single app could guide the shopper through multiple venues and public spaces.
Users concerned about privacy can simply opt out. Either by not downloading the app or, if they have the app, but not taking their phone out and turning it on in the venue.
VLC offers the ability to go beyond wayfinding by allowing organizations to communicate with users and provide a more meaningful experience.
Consider retail. The infrastructure is there. 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.
This could include product advertising, coupons, cross promotion and upselling messages for specific merchandise; virtual greetings; friend locator; guided tours and storytelling; and gaming such as treasure hunts.
The possibilities, which vary by application, are numerous.
In the future, retail stores may end up competing another level—who can deliver the best digital experience for their customers.
The VLC system consists of VLC-enabled LED luminaires; mapping and application software, which typically will reside on a Cloud; and a database that houses a diagram of merchandise locations and luminaire location coordinates.
The luminaires are general lighting luminaires but with a modulator installed on a separate board or embedded in the LED driver. VLC functionality is part of the luminaire, so installation is the same. Aside from VLC functionality, the luminaire would be selected using the same criteria as selecting any other good lighting product. They will be sold through familiar lighting industry channels.
Coverage is seamless and wall to wall. Systems are highly scalable.
Solutions are being developed by GE, Acuity Brands, LG Innotek and Philips. Some of these companies are working with technology partners such as Qualcomm Technologies, Inc. (Lumicast VLC technology) and ByteLight. Acuity and GE have commercialized the technology and have been working with retailers to implement trial installations. A general rollout is expected in 2016.
Manufacturers are focusing on delivering good VLC-enabled lighting. Integrating hardware and software into a single delivered solution may fall to authorized resellers, partners or other players. These firms will produce custom apps for organizations to leverage the VLC capability into a meaningful user experience.