Holocube: 3D Opitcal IoT Connections via Software Defined Pepper's Ghost

Optical wireless communication (OWC) has inherent location aware and spatial reuse advantages over RF-based technologies due to the Line-of-Sight (LoS) propagation of optical signals. Hence, OWC presents a fresh opportunity for effective and secure IoT connectivity and data transmission. However, most OWC systems design transmitter as a point source without considering its spatial diversity in data delivery in 3D space, which is not suitable for real-world mobile IoT connections among devices and users. In this paper, we design and implement HoloCube, which provides 3D optical IoT connections via software defined optical camera communication and Pepper's ghost effect. At the heart of the HoloCube design is multiple virtual 3D hollowed-out cubes with adaptive Spatial-Color Shift Keying (SCSK) modulation. Specifically, the virtual cube seen from various directions has constant structure but embeds different data over time. The cube's positioning elements provide double reference for both 3D reconstruction (spatial) and robust color decoding (spectral). Our comprehensive experiments demonstrate that HoloCube achieves practical 3D omnidirectional IoT connections with 70 Kbps goodput at 4 m in real-world indoor setting.