DynaLight: A Dynamic Visible Light Communication Link for Smartphones

Nowadays, Visible Light Communication (VLC) has attracted the attention of the scientific community due to its great potential in creating smart communication links. Exploiting visible light modulations, could in time enable Internet connectivity via light lamps. Recent research studies have shown that modern smartphones have the ability to capture high frequency light patterns and increase the applicability of VLC links, enabling smart applications. However, creating flexible camera-based VLC links brings-up several challenges that are introduced by the diversity of the available devices. Firstly, existing VLC systems offer inflexible setups that are designed to operate at fixed distances. This fact causes problems when it comes to varying the distance between the transmitter and the receiver. This thesis introduces DynaLight: an adaptive line-of-sight VLC system for smartphones that dynamically adjusts and maximizes its channel capacity by estimating the distance between the transmitter and the receiver. Secondly, the wide diversity in smartphones’ hardware introduces problems when it comes to implementing a generic VLC link for market smartphones. In order to increase the applicability of our system, we chose to utilize inexpensive hardware, that introduce performance limitations, such as limited camera control. We present an image processing pipeline that identifies and overcomes effects that are caused by off-the-shelf hardware, and we further increase the amount of information, that can be extracted, by 40%. Last but not least, we develop a smartphone application that implements our enhancements and draws attention to synchronization challenges. Our conclusions indicate that the applicability of smartphone VLC links will be further extended due to the rapid evolution of modern smartphones.