With LED automotive lighting now becoming commonplace, newer automobiles have the ability to communicate with each other (V2V communications) and with roadside infrastructure by quickly flashing their lights (LiFi) instead of using radio protocols. Researchers at OKATEM—the Centre of Excellence in Optical Wireless Communication Technologies at Ozyegin University in Turkey—have developed an OFDM-based LiFi demonstrator for V2V (vehicle-to-vehicle) and V2I (vehicle-to-infrastructure) applications that has achieved 50Mbps communications between vehicles as far apart as 70m in a lab atmospheric emulator.
Inside the OKATEM LiFi Atmospheric Emulator
The demo system is based on PXIe equipment from National Instruments (NI) including FlexRIO FPGA modules. (NI’s PXIe FlexRIO modules are based on Xilinx Virtex-5 and Virtex-7 FPGAs.) The FlexRIO modules implement the LiFi OFDM protocols including channel coding, 4-QAM modulation, and an N-IFFT. Here’s a diagram of the setup:
Researchers developed the LiFi system using NI’s LabVIEW and LabVIEW system engineering software. Initial LiFi system performance demonstrated a data rate of 50 Mbps with as much as 70m between two cars, depending on the photodetectors’ location in the car (particularly its height above ground level). Further work will try to improve the total system performance by integrating advanced capabilities such as multiple-input, multiple-output (MIMO) communication and link adaptation on the top of OFDM architecture.
This project was a 2017 NI Engineering Impact Award Winner in the RF and Mobile Communications category last month at NI Week. It is documented in this NI case study.