Cost-effective communication through visible light

Abstract

Visible light communication (VLC) is an alternative to radio frequency communication. It has two advantages: first, it uses a wide frequency spectrum and second, it offers an intrinsic security dimension since the light cannot pass through walls. We present a cost-effective and energy-efficient system based on VLC for video transmission. Our system could be easily implemented without introducing major modifications to the existing infrastructure. This system does not entail special devices, nor does it require installing drivers. We overcome three main research challenges: 1) removing the noise caused by the ambient light and recovering data, 2) reaching transmission debit enabling high-quality video running fluidly, 3) establishing a distance between the transmitter and the receiver long enough to facilitate the use of the system in real conditions. We implemented a visible light communication prototype operating at 4 Mb/s capable of exceeding a distance of 2 meters. The transmitter is based on a regular white LED. Due to its nanosecond response and high sensitivity to light, the photodiode PD is the main component of the receiver. The system is based on an On-Off keying modulation and demodulation technique. A cyclic redundancy check (CRC) is implemented within the developed software to reduce the bit error rate (BER)._This communication technology can be implemented where radio frequency communication cannot, for example, in hospitals. In perspective, we intend to make progress at the software-level to enable realtime video transmission.