We would like to congratulate Malte Hinrichs, research associate for metro, access, and in-house networks in the Photonic Networks and Systems (PN) department at the Fraunhofer Heinrich Hertz Institute (HHI), on successfully completing his doctorate! In his dissertation entitled “Physical Layer Design for Pulsed Modulation Optical Wireless Communications,” he has made an important contribution to the further development of LiFi systems. LiFi systems are wireless communication systems that transmit data via light rather than radio waves, as is the case with Wi-Fi.
The aim of the work was to increase the range and reduce energy consumption by integrating pulsed on-off keying (OOK) modulation as an alternative to the complex and energy-intensive orthogonal frequency division multiplexing (OFDM) method. The results show that digital signal processing (DSP) techniques previously developed for OFDM can also be used for OOK with only minor adjustments. This facilitates integration into already standardized systems.
The dissertation comprises a detailed evaluation of the existing physical layer 802.15.13 PM-PHY, the extension of the methods used there to increase throughput, and the demonstration of multi-Gbit/s transmission with a laser-based transmitter. Particularly noteworthy is the 39% reduction in overhead in PM-PHY and the successful demonstration of data rates of up to 4.25 Gbit/s with a VCSEL-based transmitter for LiFi applications.
Malte Hinrichs began working at Fraunhofer HHI as a student assistant in 2015 and has been a research associate since 2017. His research focuses on optical wireless communication and fiber optic networks in the access area. He is the author or co-author of 26 scientific publications and 16 contributions to standardization projects.
The doctoral committee consisted of Prof. Giuseppe Caire, Ph.D. (chair), Prof. Ronald Freund, Prof. Volker Jungnickel, Prof. Jean-Paul Linnartz (TU Eindhoven), and Prof. Harald Haas (University of Cambridge).
This work represents a significant step forward for LiFi research at Fraunhofer HHI – towards energy-efficient, powerful, and sustainable optical wireless communication systems.