Design of wireless optical access system using LED based android mobile

This report develops a prototype to demonstrate a directional wireless visible light communication (VLC) system based on Android Mobile. In this system, Two android mobiles can transmit local data to each other simultaneously. The system consists of two parts, the hardware and the software. The design of hardware is based on the USB port integrated in the Android Mobile. The development of software utilizes the protocol of AOA (Android Open Accessory) which is a new feature in Android 3.1 or more advanced version whereby a USB host device can connect to the Android device, allowing data transmission between Android devices over USB interfaces. Thus, the driver of the hardware needn´t be added into the kernel of android. Combing with a USB port on one board, it can achieve up to 2Mbps bit rates error free, which is mainly limited to the USB bridge circuit between two mobiles for data transmission such as text, audio and video. The software is used to set the transmission data rate, control bits, check bits so as to achieve real-time and directional transmission between two mobile devices with a USB port. This paper also shows the experimental results of the Q-factor of the eye diagram and bit rate during system transmission. The range and the angle of communication are also discussed in the paper.