Metameric modulation for diffuse visible light communications with constant ambient lighting

Advances in solid-state lighting are renewing interest in the adoption of the visible spectrum for optical wireless communications. Under the luminaire-as-transmitter model, wireless communication is achieved by modulating LED(s) that must simultaneously meet the illumination mission. Illumination requirements include maintaining energy efficiency, constant color and intensity control whereas communications requirements are speed and BER goals. In this paper we explore the perceptual qualities of visible light from LED luminaires to render color. We then propose a novel modulation scheme for visible light communications which can maintain constant perceived ambient lighting. By using D>;3 LEDs, multiple lighting states that are indistinguishable to humans but are distinguishable to an electronic receiver can be achieved. Changes between these states are detected as intensity modulation in different wavelength bands.