Continuous synchronization for LED-to-LED visible light communication networks

Off-the-shelf Light Emitting Diodes (LEDs) and low-cost microcontrollers provide the foundation for networking using the visible light as communication medium. These networks require fast and stable synchronization and a distributed protocol to handle shared medium access. We present and evaluate a physical layer and a distributed, contention-based medium access control protocol that enables reliable communication over room-range distances; both are implemented in software using low-cost commercial off-the-shelf building blocks. Experiments with a testbed consisting of embedded devices equipped with only LEDs demonstrate the scalability of this approach. The performance evaluation indicates that Visible Light Communication is a reliable solution for more than ten devices to bring low-cost and non-complex connectivity to a large number of devices.