Alternative wireless technology achieves stable outdoor data transmission

Researchers at Tokyo Polytechnic University have developed a low-cost visible light communication (VLC) system using commercially available hardware that enables stable outdoor data transmission even under strong ambient light conditions, such as direct sunlight exceeding 90,000 lux. The system achieves reliable data rates up to 3.48 Mbit/s over distances of about 3 meters by implementing a novel 8B13B line coding scheme on an FPGA connected to a Raspberry Pi. This coding scheme uses a return-to-zero format with balanced logical bits to suppress flicker and maintain synchronization, and it is robust against pulse-width distortions caused by LED characteristics. This VLC system addresses key challenges that have hindered practical deployment, including sensitivity to ambient light and waveform distortion, by employing multiple photodiodes and a narrow-band optical filter to reduce background interference. The technology is particularly promising for intelligent transportation systems (ITS), where traffic lights and street lamps could serve as communication nodes to transmit data such as intersection or blind-spot video information to vehicles