ABSTRACT
Visible light communication (VLC) is an important application of optical wireless communications techniques and refers to unguided optical transmission via the use of light emitting diodes (LEDs). LED lighting offers many advantages over conventional lighting, such as low power consumption, low cost, high luminance efficiency, long lifetime, etc. For these reasons, LEDs have become strong in the lighting market compared to traditional lighting solutions. In many indoor environments, there exists a strong ambient radiation arising from sunlight and non-transmitting lighting sources, which induces noise in a VLC receiver. In order to maximize signal-to-noise ratio, it is therefore desirable to employ an optical concentrator to increase the effective collection area and optical filters to attenuate ambient radiation. Intensity modulation is commonly used in VLC where the intensity of the emitted light signal is modulated. Therefore, the modulated signal must be real and positive in the baseband. The frequency responses of VLC channels are relatively flat near direct current.
