Li-Fi (optical wireless transmission, light fidelity) enables mobile communication with light. Li-Fi is used as a complement to radio, where higher user density requires more capacity. Moreover, Li-Fi fulfills special safety and electromagnetic compatibility requirements. Nowadays, a Li-Fi cell has 1-10 m diameter and delivers data rates from 100 Mbit/s to 1 Gbit/s. Li-Fi is based on commercially available high-performance LEDs, which are also used for lighting, and large-area photodiodes. Technology and costs are similar to those in radio: orthogonal frequency division multiplexing (OFDM) and adaptive transmission are used as well as multiple-input multiple-output (MIMO), relay function and handover between adjecent access points.
The Fraunhofer HHI has developed Li-Fi from its basics, is contributing to standardization and supports its transfer into applications. Pilot projects are currently taking place with end users in real operating environments.
Currently applications of Li-Fi are investigated in the commercial sector (business-to-business, B2B) but can also be increasingly address the public and private environment (business-to-customer, B2C).
Further fields of application are networking street lights (smart city), underwater, in medical facilities and in airplanes.