ABSTRACT
In last few years, we have seen a growing research in visible light communications (VLC), and the idea of using LEDs for both illumination and data communications. The main drivers for this technology include the increasing popularity of solid-state lighting, longer lifetime of high-brightness LEDs compared to other sources of artificial light like the incandescent light bulbs, high bandwidth/data rate, data security, no health hazards and low power consumption. The dual functionality provided by VLC (i.e., lighting and data communication from the same high-brightness LEDs) has created a whole range of interesting applications, including but not limited to home networking, high-speed data communication via lighting infrastructures in offices, car-to-car communication, high-speed communication in aeroplane cabins, in-trains data communication, traffic lights management and communications to name a few. The levels of power efficiency and reliability offered by LEDs today are by far superior compared to the traditional incandescent light sources used for lighting. Although the high-brightness white LEDs used in solid-state lighting are still a lot more expensive than the incandescent or compact fluorescent lamp that they are meant to replace, it is expected that the prices will drop considerably with time and wider adoption. In fact, solid-state lighting is anticipated to gain a lot more traction with the recent ban on incandescent light bulbs in Europe, Australia and other countries of the world. Recent research in VLC has successfully demonstrated data transmission at over 500 Mbps over short links in office and home environments. Further research and developments will open up new possibilities to partly resolve some of the issues associated with the present-day infrared, radio/microwave communication systems and lighting technologies. This chapter gives an overview of the visible light communication technology, highlighting the fundamental theoretical background, devices available, modulation and diming techniques and system performance analysis. Multiple-input–multiple-output and cellular visible light communication systems are also covered in this chapter.
