Reliable and bidirectional camera-display communications with smartphones

Wireless technologies such as WiFi and Bluetooth are widely used for mobile data communications. However, these technologies are affected by interference resulting from shared access to unlicensed frequency bands. Visible light communication is an alternative means for data exchange over an optical channel. It has several advantages over currently used radio-based technologies, including a full-duplex channel and limited interference from other sources. We designed and implemented a system for bidirectional visible light communications between smartphones. Specifically, our solution employs dynamically changing Quick Response (QR) codes shown on the display of one mobile phone to encode the data and the front-facing camera of another phone to receive the data. We devised a supporting communication protocol for reliable communications and realized a file exchange application. Moreover, we carried out an experimental evaluation of our system with focus on communication performance and power consumption. The obtained results show that our solution is reliable and comparable with existing radio-based schemes from the user perspective.