Reflection based coupling efficiency enhancement in a fluorescent planar concentrator for an optical wireless receiver.
TL;DR: In this article, an analysis of the light coupling efficiency enhancement in the electrical power gain is presented, in particular a practical method to improve the coupling efficiency by introducing edge and back reflection using Lambertian-, specular-, and retro-reflectors is presented.
Abstract: Fluorescent planar concentrators have been proposed as optical concentrators that can have both a wide field of view and a high optical gain stemming from a large collection area for optical wireless communications. However, the fluorescent concentrators with such a large collection area often lead to a low light coupling efficiency due to the edge coupling mechanism leading to a considerable optical power loss. In this work, an analysis of the light coupling efficiency enhancement in the electrical power gain is presented. In particular, a practical method to improve the coupling efficiency by introducing edge and back reflection using Lambertian-, specular-, and retro-reflectors is presented. It is demonstrated that by choosing the optimal reflectors, the received signal strength can be improved by more than a factor of two. Also demonstrated with the proposed method is a data rate more than 1.12 Gbps with bit error rate less than 3.8 × 10−3 using a DC-biased optical orthogonal frequency division multiplexing. This is, to the best of our knowledge, the first Gbps class demonstration using a commercial fluorescent planar concentrator.
Citations
More filters
TL;DR: In this paper , the authors describe the development of an organic photodiode (OPD) receiver for high-speed optical wireless communication, which achieves the highest data rate ever achieved on an OPD-based VLC system by a factor of 40 over the previous fastest reported.
Abstract: The present work describes the development of an organic photodiode (OPD) receiver for high‐speed optical wireless communication. To determine the optimal communication design, two different types of photoelectric conversion layers, bulk heterojunction (BHJ) and planar heterojunction (PHJ), are compared. The BHJ‐OPD device has a −3 dB bandwidth of 0.65 MHz (at zero bias) and a maximum of 1.4 MHz (at −4 V bias). A 150 Mbps single‐channel visible light communication (VLC) data rate using this device by combining preequalization and machine learning (ML)‐based digital signal processing (DSP) is demonstrated. To the best of the authors' knowledge, this is the highest data rate ever achieved on an OPD‐based VLC system by a factor of 40 over the previous fastest reported. Additionally, the proposed OPD receiver achieves orders of magnitude higher spectral efficiency than the previously reported organic photovoltaic (OPV)‐based receivers.
5 citations
TL;DR: A smart license plate receiver incorporated with a fluorescent concentrator is proposed, enabling a fast vehicle-to-vehicle communication with a large field of view and high optical gain, and real-time video streaming through the beam-steering channel is presented.
Abstract: Vehicle-to-vehicle communication based on visible light communication has gained much attention. This work proposes a smart license plate receiver incorporated with a fluorescent concentrator, enabling a fast vehicle-to-vehicle communication with a large field of view and high optical gain. Communication performance is experimentally analyzed using off-the-shelf light-emitting diode-based headlamps for low-latency direct line of sight channel. Additionally, a blue laser diode-based beam-steering and tracking system, through image processing of taillights with a steerable mirror, is investigated. Data rates of 54 Mbps from the headlamps and 532 Mbps from the beam-steering channel with ±25° are demonstrated. In addition, real-time video streaming through the beam-steering channel is presented.
1 citations
TL;DR: In this paper , the authors introduce a new and flexible way of creating fluorescent optical antennas, which is a glass capillary which is filled with a mixture of epoxy and a fluorophore before the epoxy is cured.
Abstract: The use of fluorescent optical antennas in visible light communications (VLC) systems can enhance their performance by selectively absorbing light from the transmitter and concentrating the resulting fluorescence, whilst preserving a wide field of view. In this paper, we introduce a new and flexible way of creating fluorescent optical antennas. This new antenna structure is a glass capillary which is filled with a mixture of epoxy and a fluorophore before the epoxy is cured. Using this structure, an antenna can be easily and efficiently coupled to a typical photodiode. Consequently, the leakage of photons from the antenna can be significantly reduced when compared to previous antennas created using microscope slides. Moreover, the process of creating the antenna is simple enough for the performance of antennas containing different fluorophores to be compared. In particular, this flexibility has been used to compare VLC systems that incorporate optical antennas containing three different organic fluorescent materials, Coumarin 504 (Cm504), Coumarin 6 (Cm6), and 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), when a white light-emitting diode (LED) is used as the transmitter. Results show that, since it only absorbs light emitted from the gallium nitride (GaN) LED, a fluorophore that hasn't previously been used in a VLC system, Cm504, can result in a significantly higher modulation bandwidth. In addition, the bit error rate (BER) performance at different orthogonal frequency-division multiplexing (OFDM) data rates of antennas containing different fluorophores is reported. These experiments show for the first time that the best choice of fluorophore depends on the illuminance at the receiver. In particular, when the illuminance is low, the overall performance of the system is dominated by the signal-to-noise ratio (SNR). Under these conditions, the fluorophore with the highest signal gain is the best choice. In contrast, when the illuminance is high, the achievable data rate is determined by the bandwidth of the system and therefore the fluorophore that results in the highest bandwidth is the best choice.
1 citations
References
More filters
Southeast University1, ShanghaiTech University2, Beijing University of Posts and Telecommunications3, University of Electronic Science and Technology of China4, China Mobile Research Institute5, University of Southampton6, University of Waterloo7, University of Technology, Sydney8, University of Manchester9, University of Edinburgh10, Huawei11, Linköping University12, Queen's University Belfast13, Georgia Institute of Technology14, University of Surrey15, Princeton University16, Dresden University of Technology17
TL;DR: 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.
Abstract: The fifth generation (5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability, and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation (6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle (UAV) communication networks, thus achieving a space-air-ground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6 GHz, millimeter wave (mmWave), terahertz (THz), and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence (AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.
935 citations
700 citations
TL;DR: This study is based on ray tracing, which allows for an accurate description of the interaction of rays emitted from the lighting source within a specified confined space and is capable of obtaining channel impulse responses for any nonideal sources, as well as specular and mixed specular-diffuse reflections.
Abstract: In this paper, we present a comprehensive channel modeling and characterization study for visible light communications. Our study is based on ray tracing, which allows for an accurate description of the interaction of rays emitted from the lighting source within a specified confined space. Contrary to existing works, which are mainly limited to ideal Lambertian sources and purely diffuse reflections, our approach is capable of obtaining channel impulse responses (CIRs) for any nonideal sources, as well as specular and mixed specular–diffuse reflections. Furthermore, we can precisely reflect the presence of objects (e.g., furniture) and wavelength-dependent reflection characteristics of surface materials (e.g., ceilings, floor, walls, and furniture) in a channel study. As case studies, we consider a number of indoor environments with various dimensions and different surface materials, i.e., plaster, gloss paint, wood, aluminum metal, and glass. We further consider various scenarios with different transmitter specifications (i.e., single versus multiple transmitters and array type) and receiver specifications (i.e., location and rotation). For each environment, we obtain CIRs and present a channel characterization study where channel parameters, such as channel DC gain, root mean square (RMS) delay spread, coherence bandwidth, and mean excess delay, are obtained. We also make one-to-one comparisons between infrared and visible-light CIRs for the same environments to emphasize the differences between two optical bands.
270 citations
TL;DR: It is envisaged that VLC will become an indispensable part of 6G given its high-speed transmission advantages and will cooperate with other communication methods to benefit the authors' daily lives.
Abstract: 6G networks are expected to provide extremely high capacity and satisfy emerging applications, but current frequency bands may not be sufficient. Moreover, 6G will provide superior coverage by integrating space/air/underwater networks with terrestrial networks, given that traditional wireless communications are not able to provide high-speed data rates for nonterrestrial networks. Visible light communication (VLC) is a high-speed communication technique with an unlicensed frequency range of 400-800 THz and can be adopted as an alternative approach to solving these problems. In this article, we present the prospects and challenges of VLC in 6G in conjunction with its advances in high-speed transmissions. Recent hot research interests, including new materials and devices, advanced modulation, underwater VLC (UVLC), and signal processing based on machine learning, are also discussed. It is envisaged that VLC will become an indispensable part of 6G given its high-speed transmission advantages and will cooperate with other communication methods to benefit our daily lives.
247 citations
TL;DR: This paper explains what Light-Fidelity (LiFi) is and argues that it is a 5th Generation (5G) technology and illustrates the potential impact this technology can have across a number of existing and emerging industries.
224 citations