Visual wireless communications with smartphones

Abstract

The advent of smartphones has certainly brought many advantages for communications among people. Due to their diverse features, smartphones allow to exchange information in different ways. The most widespread communication technologies for mobile devices - such as WiFi, Bluetooth and Long Term Evolution - exploit wireless transmissions based on electromagnetic radio signals. However, the use of these technologies present some issues with respect to security, coverage and interference.

Recent studies have revealed new approaches for data exchange, such as visible light communication. Using an optical channel for data transmission provides interesting advantages over current technologies: the use of unlicensed spectrum, no interference with radio signal, secure communication and no need for a special infrastructure.

In this thesis, we implemented an application that transfers data between smartphones through visible light communications. To this purpose, the application employs QR codes shown on the display to encode transmitted data and the front-facing camera for receiving the data. We also designed a supporting communication protocol for ensuring a successful transmission between two smartphones. Finally, we evaluated our solution in terms of power consumption and communication performance. The results showed that our solution is suitable for exchanging files of small size.