Channel characterization for indoor visible light communications

Through the numerical simulation of the channel impulse response, we investigate the limitation on the data rate due to multipath reflections for an indoor visible light communication system. Three different metrics of channel are studied for medium-sized and large rooms, namely the root-mean-square delay spread, 3-dB bandwidth, and signal-to-interference ratio. To focus on the channel effect, we assume no bandwidth constraint on the LEDs and consider simple intensity modulation techniques excluding discrete multitone modulation. We show the interest of the proposed signal-to-interference ratio metric in determining the necessity of channel equalization at the receiver.