VideoBack: High Quality Video Backscatter with Ambient WiFi

Recent works have achieved considerable success in increasing the transmission rate of video streaming backscatter communications. However, they do not consider the ease of deployment in real-world environments where these dedicated excitations are not readily available. In addition, these works are transmitted with lower image resolution, and the images received by users are not eye-friendly. In this paper, we propose VideoBack, a high quality video backscatter system with commercial WiFi excitation for easy-to-use monitoring. The key idea is to perform JPEG compression on high-pixel images to adapt to intermittent ambient WiFi transmission. This approach allows ambient commercial routers to be used for excitation. Furthermore, our work enables high-quality video transmissions by devising a low bit error rate decoding scheme. We build a prototype of VideoBack and use a commercial WiFi adapter to excite the tag to realize the transmission and reception of video. The prototype uses RF signals to charge and store energy. Our evaluations show that VideoBack can transmit images at a throughput of nearly 250 kbps with bit error rate below 0.0005 within 9 meters, while the images only have minor distinctions. VideoBack can support sending one frame of image after just 2 seconds of power acquisition within 3m.