i-LightHouse: A Visible Light Communication system for the visually impaired

This paper introduces a Visible Light Communication (VLC) system using an LED sign panel, which allows the provision of broadcast-type information in public spaces. This system provides an additional function to an LED advertisement panel; the panel not only displays an advertisement, but also transmits wirelessly to other devices. We suggest its use in benefit of the visually impaired. They can obtain local information by using this system, named i-LightHouse (i-LH). For this purpose, i-LH transmits a long-range navigation signal to direct users to the LED sign panel and a short-range signal to download content information to the users´ devices. We propose its modulation scheme which can multiplex the navigation and content information at the same time. In this system, the interruption by a passerby and ambient lights may degrade the communication performance. On these issues, we propose an error correcting method and a filter to mitigate the interference of them and evaluate the effectiveness.