Lightweight Display-to-device Communication Using Electromagnetic Radiation and FM Radio

This paper presents Shadow, a novel display-to-device communication system working in radio frequency. It leverages Electromagnetic Radiation (EMR) signals emanating from displays to transmit information. Specifically, Shadow modulates the high-frequency electric signals flowing in the display interface and makes the leaked EMR signals fall into the FM band. In this way, nearby mobile devices can receive information from the display through FM receivers. Compared with other display-to-device communication approaches, Shadow does not rely on cameras, and is thus more lightweight and requires fewer user actions. Furthermore, Shadow's transmissions do not incur any degradation in the display quality, as they only take place in the Blanking Interval, which will not be shown on the display panel. Shadow requires no modification to existing hardware. The prototype is implemented with commodity display systems and mobile devices. Results show that it can achieve 1.5 kbps at distances of up to 20 cm from the display panel.