Non-line-of-sight WDM-MIMO optical camera communications with the DBPWR algorithm

• Published in: Optics communications Vol. 518; p. 128371
• Main Authors: Jiang, Ningcong, Lin, Bangjiang, Lai, Qiwei, Huang, Tianming, Ghassemlooy, Zabih, Younus, Othman Isam, Luo, Jiabin, Xie, Yufang, Dai, Lingfeng, Huang, Zhuo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2022
• Subjects: Multiple-input multiple-output (MIMO); Non-line-of-sight (NLOS); Optical camera communication (OCC); Visible light communications (VLC); Wavelength division multiplexing (WDM); Visible light communications (VLC); Multiple-input multiple-output (MIMO); Optical camera communication (OCC); Wavelength division multiplexing (WDM); Non-line-of-sight (NLOS)
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2022.128371

Non-line-of-sight (NLOS) optical camera communications (OCC) is a potential wireless communication technology, which offers robustness to blocking and blooming effect, higher data throughput over longer transmission distances compared with line-of-sight OCC. In this work, we propose a wavelength division multiplexing (WDM)-multiple inputs multiple outputs (MIMO) NLOS OCC system with multi-level pulse width modulation (MPWM) and difference-based pulse width recognition (DBPWR) schemes. Signals on different color channels are separated through the RGB filter of the CMOS camera, while MPWM signals on the same color channel are separated using the DBPWR algorithm. Compared with the conventional threshold-based demodulation scheme, the proposed DBPWR scheme has lower complexity, higher reliability, and improved sampling frequency offset tolerance. A total data rate of 10.8 kb/s is experimentally demonstrated over more than 2 m NLOS link using the proposed WDM-MIMO OCC system, which is sufficient in many Internet of things applications. •In this work, we first time employ the wavelength division multiplexing (WDM) and multiple inputs multiple outputs (MIMO) for NLOS OCC.•A total data rate of 10.8 kb/s is experimentally demonstrated over more than 2 m NLOS link, which is the highest reported so far to the best of our knowledge.•Signals on different color channels are separated through the RGB filter of the CMOS camera, while MPWM signals on the same color channel are separated using the DBPWR algorithm.•Through the proposed MPWM and DBPWR algorithm, we have addressed the implementation challenge of WDM-MIMO in a NLOS OCC link.