Showing papers by "Frans Huijskens published in 2023"
DOI•
TL;DR: A beam-steered Gigabit Ethernet (GbE) bidirectional OWC system with user-hosted automatic self-calibrated alignment of the upstream beams has been designed and realized, using stepper motor translators, miniature retro-reflectors and a novel self-alignment center-of-gravity (CoG) algorithm as discussed by the authors .
Abstract: A beam-steered Gigabit Ethernet (GbE) bidirectional OWC system with user-hosted automatic self-calibrated alignment of the upstream beams has been designed and realized, using stepper motor translators, miniature retro-reflectors and a novel self-alignment center-of-gravity (CoG) algorithm. Broadband receivers with a Field-of View (FoV) >10 degree are used, which relaxes beam alignment. The accuracy of the CoG algorithm and the impact of lens aberrations in the upstream beam launching is analyzed. A good accuracy of the automated upstream beam steering within 200 μm relative to the center of the upstream receiver's aperture has been found up to a beam incident angle of 10 degree; this is well within the 25 mm aperture and the FoV of the upstream receiver. Hereto a relatively simple low-aberration triplet lens is used at the user site. The upstream beam alignment takes less than 10 seconds. The full system laboratory setup provides individual narrow beams for high user densities. It also includes automatic self-calibrated alignment of the downstream beams using similar retroreflector technology and a wavelength-tuned beam steering. TCP measurements show transfer speeds of 940 Mbit/s per user within 10 degree FoV. Real-time high-definition GbE video streaming to laptop computers via individual bidirectional OWC links has been demonstrated.
DOI•
TL;DR: In this article , the authors present a novel indoor communication network using 1-mm core diameter step-index plastic optical fibres as feeder line, and using the light emitted by the POF-end for wireless data transmission, creating a fully passive AP.
Abstract: We present a novel indoor communication network using 1-mm core diameter step-index plastic optical fibres as feeder line, and using the light emitted by the POF-end for wireless data transmission, creating a fully passive access point (AP). This has the advantage of not requiring electrical powering, resulting in low maintenance. Due to the large numerical aperture, the light emitted by the POF is extremely divergent, thus a lens must be placed in front of the POF-end to adjust the size of the coverage area to enable users movement or to increase the number of users served by the wireless link. We present a theoretical model for both multiple-input multiple-output (MIMO) transmission modes, spatial diversity (SD) and spatial multiplexing (SM), using orthogonal frequency division multiplexing (OFDM). We report the system throughput, that is estimated using the singular value decomposition (SVD) of the experimentally measured channel matrix $\mathbf {H}(f)$. We then present experimental results applying both SD and SM concepts and compare with the theoretical results. We demonstrate that this passive AP concept using OFDM achieves throughputs of around 5.2 Gbps when SM is applied, and 3.8 Gbps when SD is applied. Furthermore, we use eye-safe visible light laser for the POF feeder which, due to optical losses by POF and components, limited the wireless link to 1 m only and the coverage area to 45 cm diameter. We believe the proposed system represents a low-cost, high-capacity, highly secure, interference free wireless system, suitable for next generation for industrial and home applications