What is the fine-grained topic of the following text: Visitors to the 2019 embedded world Exhibition & Conference, being held from 26-28 February in Nuremberg, can experience the possibilities of optical wireless data transmission in an augmented reality scenario at the Fraunhofer IPMS Booth 123 in Hall 3. Only return the topic.
Optical wireless data transmission demonstration at the 2019 embedded world Exhibition & Conference