Optical Wireless Transmission – Li-Fi


Modern navigation systems or traffic information services have been communicating wirelessly with cars and drivers for years. In some situations, however, wireless capacity reaches its limits. Here, an optical solution – Visible Light Communication or Li-Fi for short – offers a modern and powerful complement. With the help of a modulator developed by Fraunhofer Heinrich Hertz Institute, LED lamps are switched on and off very quickly and data is sent to the receiver as ones and zeros – invisible to the human eye. Transmission via LEDs offers many advantages. LEDs are already widely used, energy-efficient and cost-effective due to the energy savings. A photodiode on the receiver device captures the light and converts the information into electrical impulses. This enables bidirectional data transmission. In the future smart city, there will be numerous potential applications for data transmission with light. Li-Fi enables a real time exchange of a wide range of information between road users and the local infrastructure. Traffic-relevant data, such as map updates and multimedia data can also be exchanged with the data cloud. In a tunnel, wireless connections are susceptible to interference. Li-Fi offers the possibility to transmit data optically via tunnel illumination or from car to car. This allows information to be streamed live and avoids data congestion on the wireless system. Local events also need local solutions and should not burden other communication channels. Fast image transfer from car to car immediately creates a good overview. This avoids stress and significantly relieves drivers. In the future, every communication channel will be used for immediate information transmission. Even street lighting can be used for Li-Fi. Various local information, such as a traffic jam caused by a traffic accident, can be transmitted via Li-Fi modules between cars and street lamps. Optical data transmission helps to better assess the traffic situation and to react safely and appropriately. Cars approaching a traffic jam are informed in time; suitable alternatives can be suggested. Saving all parking garage maps of a city or of the whole country requires an unnecessary amount of memory space. It is important to get the information on the spot, where it is needed. Especially in underground car parks, radio communication coverage is often not available. Illumination, on the other hand, is available everywhere. Local optical transmission enables the exchange of large amounts of data. It works like a wireless cable extension. Li-Fi can do even more: In future autonomous driving, unforeseen situations can lead to traffic jams. For example a delivery van blocking the road. In such a case, autonomous vehicles have to stop the drive for safety reasons. Therefore, it is important to transmit current road situations quickly. This should happen in a timely manner and in the immediate proximity, so that other road users can be informed quickly. The future Car-to-X communication will be a part of the 5G technology. Li-Fi can significantly increase the performance of future communication systems. For the development of applications with Li-Fi, Fraunhofer HHI offers finished components as “plug and play solutions”. Modular units can also be individually integrated into customer technologies, e.g. in the automotive industry. Please do not hesitate to contact us.

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