1 research outputs found
Enabling Multiple Access for Non-Line-of-Sight Light-to-Camera Communications
Light-to-Camera Communications (LCC) have emerged as a new wireless
communication technology with great potential to benefit a broad range of
applications. However, the existing LCC systems either require cameras directly
facing to the lights or can only communicate over a single link, resulting in
low throughputs and being fragile to ambient illuminant interference. We
present HYCACO, a novel LCC system, which enables multiple light emitting
diodes (LEDs) with an unaltered camera to communicate via the non-line-of-sight
(NLoS) links. Different from other NLoS LCC systems, the proposed scheme is
resilient to the complex indoor luminous environment. HYCACO can decode the
messages by exploring the mixed reflected optical signals transmitted from
multiple LEDs. By further exploiting the rolling shutter mechanism, we present
the optimal optical frequencies and camera exposure duration selection strategy
to achieve the best performance. We built a hardware prototype to demonstrate
the efficiency of the proposed scheme under different application scenarios.
The experimental results show that the system throughput reaches 4.5 kbps on
iPhone 6s with three transmitters. With the robustness, improved system
throughput and ease of use, HYCACO has great potentials to be used in a wide
range of applications such as advertising, tagging objects, and device
certifications.Comment: 12 pages, 13 figure