TunnelLiFi: Bringing LiFi to Commodity Internet of Things Devices.

LiFi, light-fidelity, is a wireless technology that uses visible light for data transmission. It has several advantages, such as using a different part of electromagnetic spectrum than radio communication and providing enhanced privacy because light transmission is blocked by walls. Internet of Things applications with low-to-moderate data rates represent a promising arena for LiFi adoption. However, it is difficult to bring LiFi to IoT devices for several reasons, including some of LiFi's strengths. We present TunnelLiFi, a new receiver architecture that acts like a bridge between the light and radio spectrums. A key aspect of TunnelLiFi's design is the use of the unique self-oscillating mixing property of the tunnel diode oscillator, which enables the mixing of a photodiode signal with a locally generated radio frequency carrier signal while drawing under 100 μW of power consumption. In our experiments, Tunnel-LiFi demonstrates the ability to replicate the information contained in light signals onto radio signals at tens of microwatts, even in low-light conditions (300 lux) and at low bitrates (2.93 Kbps). We also show the potential of TunnelLiFi to support high bitrates. TunnelLiFi opens up new possibilities for LiFi technology by enabling communication in areas where light propagation is challenging. It also allows commodity IoT devices to receive LiFi transmissions using their existing transceivers, thus expanding the reach of LiFi.