Distributed 8×6 MIMO Experiments for Optical Wireless Communications

We experimentally investigate antenna diversity schemes for robust optical wireless communications with large coverage in industrial manufacturing environments. Our proposed scheme improves the average and peak data rates by up to 28 % and 75 %, respectively

Nonlinear digital pre-distortion of transmitter components

Based on measurements, we derive a linear and nonlinear pre-distortion tailored to the components of an optical transmitter and investigate their performance in simulations and experiments. Significant performance improvements are demonstrated for higher-order modulation formats such as 64- and 128-QAM

Four-dimensional trellis coded modulation for flexible optical transponders

We experimentally demonstrate 4-D TCM based on PDM-16QAM, PDM-32QAM and PDM-64QAM formats. A multi-rate optical transponder is enabled by only a single encoder/decoder structure. The scheme is resilient to cycle-slip events due to its 90° phase rotation invariant property

Use cases for optical wireless communication

We present results from trials in three promising uses cases for optical wireless communication (OWC): Mobile backhaul, industrial wireless, and indoor Li-Fi. We point out specific requirements and illustrate performance through measurements in typical scenarios

Multi-Gigabit Real-Time Signal Processing for Future Converged Networks

The increasing demand for higher data rates in fixed and mobile networks requires the deployment of optical fibre, which is, however, not always possible. In order to bridge such missing links wirelessly, commercial radios support 1 Gbit/s. The main limitation towards higher data rates is the baseband signal processing speed, as the range above 1 Gbit/s is not yet covered by existing chipsets. In this paper, we present a further-developed bidirectional 5 Gbit/s mm-wave link, where the previously presented link [1] has been extended so that the major impairment effects on the real radio link, namely the carrier frequency offset (CFO) and I/Q imbalance, are now compensated for. The enhanced system has shown a 5 Gbit/s transmission over a wireless link of approximately 1 m with an average error vector magnitude (EVM) of -16.9 dB. This allows for an error-free transmission using standard Forward Error Correction (FEC) method

Digital pre-distortion techniques for next generation bandwidth variable transponders

Next generation bandwidth variable transponders require digital pre-compensation techniques (DPC) to generate high order high symbol rate modulation formats. In this invited paper, we revise recently proposed DPC techniques for optical transponders

Impact of brillouin backscattering on signal distortions in single-fiber diversity loop based polarization-insensitive FOPAs

We both experimentally and numerically investigate the impact of Brillouin backscattering in single-fiber-loop based polarization-insensitive fiber-optical parametric amplifiers. We show that the loop configuration can cause distortions in the pump spectra due to Brillouin interactions of the counter-propagating pumps. This can result in significant distortions for amplified data signals at high gain when conventional highly nonlinear fibers are used. We thoroughly investigate the effect in experiments and derive a numerical model. This allows to compare the results from system experiments with 28 GBd quadrature-phase shift keying signals to system simulations showing a good agreement on the system. Based on the model, we finally estimate that a large gain (~ 20 dB) with a low optical signal to noise ratio (OSNR) penalty (0.15 dB at bit error rate of 1e-4) for the amplified data signal should be possible in a single-fiber loop with Brillouin-suppressed highly nonlinear fibers

A review of lipase immobilization on hydrophobic supports incorporating systematic mapping principles

A review of the literature covering research on the immobilization of lipases on hydrophobic supports was performed using systematic mapping (SM) concepts. This approach consists of a rigorous review of the methodology used to catalog evidence, to identify gaps at the frontier of knowledge, to identify unknown trends, and to list research groups. Our results show a wide variety of available lipases, including commercial, wild-type and recombinant strains. However, the most commonly used lipases are lipases from Thermomyces lanuginosus (TLL), Candida rugosa (CRL) or Rhizomucor miehei (RML) and lipase B from Candida antarctica (CALB). A wide variety of supports with different degrees of hydrophobicity were identified and the supports activated with a layer of octyl or octadecyl groups were the most commonly used. The advantages of lipase immobilization on these supports are discussed. Among them, the immobilization, purification, stabilization and hyperactivation of lipases in a single step stand out. Moreover, problems related to lipase immobilization by interfacial activation are highlighted (mainly enzyme release). Strategies to overcome these problems include immobilization on heterofunctional supports or intermolecular crosslinking of enzymes immobilized by physical and/or chemical agents. The possibility of increasing the capacity of supports by lipase multilayer immobilization is also discussed. Finally, the structure, distribution of the network and the frequency of co-occurrence between lipases and supports are elucidated to determine the possible hotspots and hitherto unexplored advances in knowledge. © 2023 The Royal Society of ChemistryThis work was funded by São Paulo Research Foundation (FAPESP, grant number 2016/10636-8), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES, Finance Code 001), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, project numbers 405889/2016-0 and 308212/2017-7), Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (Spanish Government) (project PID2022-136535OB-I00 and MCIN/AEI/10.13039/501100011033/) and by FEDER A Way of Making Europe funds (project PID2021-123079OB-I00), and Generalitat Valenciana (CIPROM/2021/70).Peer reviewe

Transmission of 512SP-QAM Nyquist-WDM signals

We report on the experimental realization of 28-GBd four-dimensional 512-ary set-partitioning QAM signals and investigate them in a Nyquist-WDM scenario. In transmission experiments over standard single-mode fiber, we compare them with 28-GBd PDM-16QAM and PDM-32QAM Nyquist-WDM signals

Channel measurement campaigns for wireless industrial automation

Um vernetzte und dennoch flexible Herstellungsprozesse zu ermöglichen, wird die Industrie der Zukunft voll von der Digitalisierung durchdrungen sein. In diesem Zusammenhang bieten insbesondere drahtlose Technologien Vorteile für die industrielle Automatisierungstechnik. Jedoch stellt die hohe Dichte an metallischen Objekten und die sich hieraus ergebende Mehrwegeausbreitung des Sendesignals mit Schwundkanälen eine große Herausforderung für den verlässlichen Einsatz von drahtlosen Übertragungssystemen im industriellen Umfeld dar. Um die Gegebenheiten der Signalausbreitung in industriellen Umgebungen zu erfassen, werden in diesem Beitrag die Ergebnisse verschiedener Kanalmesskampagnen präsentiert. Die Messkampagnen wurden durch die deutsche Forschungsinitiative „Zuverlässige drahtlose Kommunikation in der Industrie“ gefördert und decken drahtlose Kommunikation im optischen Spektrum sowie im Spektrum unterhalb von 6 GHz ab. Es werden statistische Analysen verschiedener Einflussgrößen des drahtlosen Kanals durchgeführt. Abschließend diskutieren wir die Bedeutung der Ergebnisse für die Entwicklung industrieller drahtloser Kanalmodelle