Distributed Multiuser MIMO for LiFi in Industrial Wireless Applications

• Published in: Journal of lightwave technology Vol. 39; no. 11; pp. 3420 - 3433
• Main Authors: Bober, Kai Lennert, Mana, Sreelal Maravanchery, Hinrichs, Malte, Kouhini, Sepideh Mohammadi, Kottke, Christoph, Schulz, Dominic, Schmidt, Christian, Freund, Ronald, Jungnickel, Volker
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-06-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers (IEEE)/Optical Society of America(OSA)
• Subjects: Access control; Computer architecture; Electronic devices; Engineering Sciences; Industrial communication; LiFi; Light fidelity; MIMO; MIMO (control systems); MIMO communication; Multiplexing; multiuser; On-Off Keying; Optical fibers; optical propagation; Optical sensors; Optical variables measurement; Optical wireless; optical wireless communications; Optics; Photonic; Reliability; spatial diversity; Time measurement; Wireless communication; Wireless communications; Wireless sensor networks; LiFi; Industrial communication; spatial diversity; optical propagation; MIMO; multiuser; optical wireless communications
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2021.3069186

We present a concept for networked optical wireless communications, also denoted as LiFi, to meet the requirements of industrial wireless applications. These are primarily mobility support with moderate data rates per device, reliable real-time communication, and integrated positioning. We describe a distributed multiuser multiple-input multiple-output architecture, serving mobile devices via an optical wireless infrastructure. The system consists of a central unit, being connected to a number of distributed optical frontends covering a larger area. Our main contribution is a medium access control protocol based on space division multiple access. Evaluation results demonstrate the advantages of joint transmission from adjacent optical frontends and the dynamic switching between spatial diversity and multiplexing. The relevance of spatial multiplexing becomes obvious through channel measurements in an indoor scenario. Moreover, we highlight a low-power physical layer based on on-off-keying for battery-powered mobile devices. Our architecture can easily integrate positioning by simultaneously measuring the time-of-flight between multiple optical frontends and the mobile device. We highlight the use of plastic optical fiber as an analog fronthaul technology and discuss the integration with other networks. The main functions described in this paper will be supported by the upcoming IEEE Std 802.15.13.