VLC-LE: Energy-Efficient and Secure Visible Light Communication for the Internet of Bodies

We present VLC-LE, a low-energy variant of Visible Light Communication (VLC) for energy-constrained devices such as on-body wearables that collect and transmit sensitive health data. VLC-LE is ultra-low-power and physically secure compared to traditional VLC, BLE, or WiFi. VLC-LE transmits data by modulating the LED at extremely low brightness levels by biasing it below its knee voltage, a method unique to VLC-LE and not previously explored in VLC technologies. The peak power consumption of VLC-LE is far less (approximate to 10 mu W), 100 times lower, compared to (approximate to mW) power consumed by traditional VLC, BLE and WiFi. Additionally, the low brightness levels of the LED in VLC-LE limit the signal transmission range to a few centimeters, improving the physical-layer security of the communication. Our specific contributions are as follows: We prototype the first version of VLC-LE, demonstrating data transfers from an embedded device to a smartphone. We created a dataset comprising 48,000 images of an LED at different brightness levels and ambient light conditions. We used this dataset to study the effect of VLC-LE on LED brightness and ambient conditions. The study helped us determine the lowest brightness level and, thus, the lowest power required for operating VLC-LE.