Wide-Coverage Beam-Steered 40-Gbit/s Non-Line-of-Sight Optical Wireless Connectivity for Industry 4.0

Abstract

In the coming Industry 4.0, there is a long-standing challenge to transfer real-time broadband data (e.g., video monitoring data) among machines. Optical wireless communication (OWC), which can easily carry tens of gigabit/s data, is a promising technology but suffering from non-line-of-sight (NLOS) limitation. In the NLOS scenario, the power of diffused light is heavily attenuated while the diffuse-induced multi-path effect suppresses the band-width of received signals. In this article, the diffuse light reflected off a rough surface (e.g., ceilings or walls) can be focused at a target receiver with an average 18-dB-power-enhancement. A record 40-Gbit/s >80°-coverage beam-steered NLOS OWC system enabled by the proposed diffuse reflection focusing (DRF) is experimentally demonstrated over a diffused 25-cm free-space link. The fast-focusing transmission matrix (TM) algorithm, which takes only 513 iterations to do the focusing, is introduced to make the DRF technique more practical for daily applications. The low-cost intensity-modulation/direct-detection (IM-DD) transmission scheme and the simple on-off keying (OOK) signal are selected to support low-cost applications. All these features exhibit its great potential for high-speed indoor wireless communications, especially in the scenarios of Industry 4.0.