Li-Fi in retail: Data transmission via light

Data is usually transmitted wirelessly, but these networks can reach their limits or be vulnerable to interference. The answer may be hanging in the lights above our heads: light as a new medium for data transmission.

This is exactly where Li-Fi comes in: Existing LED lighting is expanded into a fast, secure data network. Instead of relying on costly wireless upgrades, the technology uses light for stable connections, supports smart shelves, and enables seamless customer experiences or real-time inventory tracking. Combined with existing wireless networks, it creates resilient stores in which local infrastructure and digital omnichannel solutions work hand in hand.

Li-Fi uses LED lamps that switch on and off extremely quickly, effectively “blinking” millions of times per second. Although this is invisible to the human eye, data can be transmitted through variations in brightness.

On the transmitting side, the data stream is converted into light signals. A photodetector or a dedicated Li-Fi receiver captures these signals and converts them back into electrical data.

Depending on the system, communication is bidirectional, often using visible light in one direction and infrared or other optical methods in the other. This makes Li-Fi a fully fledged communications system that – much like Wi-Fi – enables interactive applications and real-time data processing.

In terms of range, Li-Fi typically covers just a few meters up to about 20 meters, depending on the system, light source, and environment, making it shorter-range than traditional wireless technologies. The reason is the required line of sight as well as the limited propagation of light, which does not pass through walls.

The high data rates of 100 Mbit/s to more than 1 Gbit/s are made possible by the large usable optical spectrum, which is far less congested than the radio spectrum.

Put simply, Li-Fi works a bit like Morse code with light – only much faster and bidirectional.

Since Wi-Fi and 5G are currently the dominant transmission technologies in retail, a direct comparison makes sense – especially because Li-Fi addresses precisely the points where wireless solutions begin to hit their limits. Li-Fi can offer particular advantages in dense or sensitive environments.

In retail, Li-Fi is especially suitable for areas with many devices or high requirements for stability and security – for example, IoT sensors or local data transmission.

• Indoor navigation: Using light-based positioning, a shopper’s location in the store can be captured precisely on smartphones, allowing customers to be guided directly to products.
• Smart shelves: Li-Fi transmits product information or personalized offers directly at the shelf to shoppers’ smartphones.
• Digital displays and AR applications: Content is delivered in real time via Li-Fi to displays or AR apps in the store, enabling interactive shopping experiences.
• Real-time inventory tracking: Connected sensors can transmit and update stock data immediately.
• Employee communication and task management: Staff receive tasks, status updates, and internal messages in real time on their Li-Fi-enabled devices.
• Warehouse and logistics: Autonomous transport robots communicate their position via Li-Fi and receive new assignments in real time.
• Events and pop-up stores: Li-Fi enables fast, interference-free networking of temporary retail spaces via existing lighting.

To use Li-Fi in stores or branch networks, the following are needed:

• LED lighting with integrated or retrofitted Li-Fi transmitters
• Receivers, such as USB dongles, integrated photodiodes, or specialized end devices
• Hybrid systems combining Wi-Fi/5G for seamless handoffs
• A suitable environment: line of sight, minimal obstruction, and integration into lighting controls

n a store network, the luminaires are typically connected centrally, often via PoE (Power over Ethernet). This allows power and data to be transmitted together over a single network cable, making it possible to integrate Li-Fi systems efficiently into existing infrastructures.

The standardization of IEEE 802.11bb in 2023 established an important foundation for interoperable Li-Fi systems.

Commercial solutions already exist today, particularly for specialized use cases such as industry, healthcare, or security-critical environments. Providers such as Signify and Fraunhofer are actively developing and testing relevant systems.

Li-Fi is currently used mainly in pilot projects and specific applications – especially where wireless connections are restricted or particularly high security is required.

Widespread adoption in retail still depends on factors such as hardware costs, integration into end devices, and the combination with existing wireless networks.

Li-Fi can be a meaningful complement to existing wireless technologies – especially in dense, interference-prone, or security-critical environments. The technology benefits from building on existing lighting infrastructure and tapping into a spectrum that has so far been largely underused.

At the same time, Li-Fi comes with clear limitations: The required line of sight and limited range make it unsuitable as a standalone networking technology in complex store layouts.

That means Li-Fi will not replace Wi-Fi and 5G, but rather complement them in targeted ways – above all where wireless reaches its limits or additional capacity is needed.

Over the long term, Li-Fi could establish itself as an additional network layer, especially in IoT-intensive environments – provided that costs, integration, and standardization continue to advance.

Sources: Fraunhofer IPMS, Signify Trulifi, Computer Weekly, EU-Projekt ELIoT, LiFiMAX Leitfaden