A Multi-LED Dome Bulb Prototype for Dense Visible Light Communication Networks

In this paper, we employ imaging-basedbeam-steering to enable multi-datastream visible light communication networks serving dense Internet-of-Things (IoT) deployments. We demonstrate a “dome bulb” transmitter that consists of a multi-LED array with a dome-shaped lens to separate each LED’s beam for better spatial reuse. Each LED has a Lambertian irradiance distribution that is collected efficiently and directed along a particular line-of-sight using a wide field-of-view lens system. At focus, the image of the LED array is projected to a distant conjugate plane, and LED beam divergence is minimized to the geometric limit. This improves spatial reuse by minimizing interference between adjacent beams but results in spotty illumination due to gaps between LEDs in the array. Moderate defocusing blurs the beams to increase illumination uniformity at the expense of increased cross-channel interference. We present a model for the bulb that correlates to the experimental results and quantify the performance of the prototype for dense IoT networks.