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Advances in Visible Light Communication
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Advances in Visible Light Communication

A special issue of Photonics (ISSN 2304-6732). This special issue belongs to the section "Optical Communication and Network".

Deadline for manuscript submissions: closed (31 May 2023) | Viewed by 42172

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Dr. Cuiwei He

E-Mail Website
Guest Editor
School of Information Science, Japan Advanced Institute of Science and Technology (JAIST), 1 Chome-1 Asahidai, Nomi, Ishikawa 923-1211, Japan
Interests: optical wireless communications; visible light communications; visible light positioning; modulation/demodulation techniques; digital signal processing; photon-counting receiver; machine learning; fluorescent antenna
Special Issues, Collections and Topics in MDPI journals
Dr. Wajahat Ali

E-Mail Website
Guest Editor
Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, UK
Interests: optical wireless communications (OWC); photon-counting receivers (SiPM); fluorescent concentrators; modulation techniques (OFDM/DFE-OOK); OWC for high-energy physics; eye safety for OWC
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In the past two decades, we have all witnessed a significantly growing interest in the development of visible light communication (VLC) technologies for a wide range of wireless applications. Thanks to the invention of semiconductor-based light sources, either LEDs or lasers, high-transmission bandwidths can be achieved using low-complexity intensity modulation to support Gbps data rates. The use of state-of-the-art photodetectors and advanced optics at the receiver also contributes to the development of VLC systems. Furthermore, smart signal processing algorithms and multiplexing techniques have been widely investigated to boost the data rate and/or improve the reliability of transmission. In recent research, a trend of using data-driven machine learning techniques in different VLC scenarios can be seen, and these approaches have shown very promising performances. Moreover, very interesting new interdisciplinary research is emerging regarding the use of advanced optical materials in VLC to improve the transmission performance. We hope all of these emerging techniques can make VLC a strong candidate for use in the next-generation wireless communication network.

This Special Issue aims to publish high-quality papers which study the emerging important technologies in VLC. Research areas may include (but are not limited to) the following topics:

  • Transmitter and receiver technologies for VLC;
  • Signal modulation/demodulation;
  • Advanced signal processing in VLC;
  • VLC experiments;
  • Image sensor communications;
  • Eye safety for OWC/VLC;
  • Underwater VLC;
  • Hybrid LiFi and WiFi networks;
  • Optical OFDM modulation;
  • Optical MIMO and spatial modulation;
  • Advanced optical materials in VLC;
  • Organic LEDs in VLC;
  • Photon counting receivers in VLC;
  • Machine learning and neural networks in VLC;
  • Indoor localization and positioning;
  • Optical wireless communications;
  • Vehicle-to-Vehicle VLC.

We look forward to receiving your contributions.

Dr. Cuiwei He
Dr. Wajahat Ali
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Photonics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • optical wireless communications
  • visible light communication
  • modulation/demodulation
  • Indoor localization and positioning
  • machine learning
  • photon counting

Published Papers (22 papers)

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Editorial

Jump to: Research, Review

5 pages, 185 KiB  
Editorial
Advances in Visible Light Communication
by Cuiwei He and Wajahat Ali
Photonics 2023, 10(11), 1277; https://doi.org/10.3390/photonics10111277 - 17 Nov 2023
Cited by 1 | Viewed by 1077
Abstract
Visible light communications (VLC) have been a highly popular area of research in recent years [...] Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)

Research

Jump to: Editorial, Review

13 pages, 4973 KiB  
Article
LiNEV: Visible Light Networking for Connected Vehicles
by Osama Saied, Omprakash Kaiwartya, Mohammad Aljaidi, Sushil Kumar, Mufti Mahmud, Rupak Kharel, Farah Al-Sallami and Charalampos C. Tsimenidis
Photonics 2023, 10(8), 925; https://doi.org/10.3390/photonics10080925 - 11 Aug 2023
Viewed by 1488
Abstract
DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) has been introduced to visible light networking framework for connected vehicles (LiNEV) systems as a modulation and multiplexing scheme. This is to overcome the light-emitting diode (LED) bandwidth limitation, as well as to reduce the inter-symbol [...] Read more.
DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) has been introduced to visible light networking framework for connected vehicles (LiNEV) systems as a modulation and multiplexing scheme. This is to overcome the light-emitting diode (LED) bandwidth limitation, as well as to reduce the inter-symbol interference caused by the multipath road fading. Due to the implementation of the inverse fast Fourier transform, DC-OFDM suffers from its large peak-to-average power ratio (PAPR), which degrades the performance in LiNEV systems, as the LEDs used in the vehicles’ headlights have a limited optical power-current linear range. To tackle this issue, discrete Fourier transform spread-optical pulse amplitude modulation (DFTS-OPAM) has been proposed as an alternative modulation scheme for LiNEV systems instead of DCO-OFDM. In this paper, we investigate the system performance of both schemes considering the light-emitting diode linear dynamic range and LED 3 dB modulation bandwidth limitations. The simulation results indicate that DCO-OFDM has a 9 dB higher PAPR value compared with DFTS-OPAM. Additionally, it is demonstrated that DCO-OFDM requires an LED with a linear range that is twice the one required by DFTS-OPAM for the same high quadrature amplitude modulation (QAM) order. Furthermore, the findings illustrate that when the signal bandwidth of both schemes significantly exceeds the LED modulation bandwidth, DCO-OFDM outperforms DFTS-OPAM, as it requires a lower signal-to-noise ratio at a high QAM order. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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18 pages, 13107 KiB  
Article
A Visible Light 3D Positioning System for Underground Mines Based on Convolutional Neural Network Combining Inception Module and Attention Mechanism
by Bo Deng, Fengying Wang, Ling Qin and Xiaoli Hu
Photonics 2023, 10(8), 918; https://doi.org/10.3390/photonics10080918 - 09 Aug 2023
Viewed by 1006
Abstract
To improve the accuracy of personnel positioning in underground coal mines, in this paper, we propose a convolutional neural network (CNN) three-dimensional (3D) visible light positioning (VLP) system based on the Inception-v2 module and efficient channel attention mechanism. The system consists of two [...] Read more.
To improve the accuracy of personnel positioning in underground coal mines, in this paper, we propose a convolutional neural network (CNN) three-dimensional (3D) visible light positioning (VLP) system based on the Inception-v2 module and efficient channel attention mechanism. The system consists of two LEDs and four photodetectors (PDs), with the four PDs on the miner’s helmet. Considering the height fluctuation of PD and the impact of wall reflection on the received light power, we adopt the Inception module to perform a multi-scale extraction of the features of the received light power, thus solving the limitation of the single-scale convolution kernel on the positioning accuracy. In order to focus on the information that is more critical to positioning among the numerous input features, giving different features of the optical power data corresponding weights, we use an efficient channel attention mechanism to make the positioning model more accurate. The simulation results show that the average positioning error of the system was 1.63 cm in the space of 6 m × 3 m × 3.6 m when both the line-of-sight (LOS) and non-line-of-sight (NLOS) links were considered, with 90% of the localization errors within 4.55 cm. During the experimental stage, the average positioning error was 11.12 cm, with 90% of the positioning errors within 28.75 cm. These show that the system could achieve centimeter-level positioning accuracy and meet the requirements for underground personnel positioning in coal mines. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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11 pages, 2282 KiB  
Article
Two-Stage Link Loss Optimization of Divergent Gaussian Beams for Narrow Field-of-View Receivers in Line-of-Sight Indoor Downlink Optical Wireless Communication (Invited)
by Xinda Yan, Yuzhe Wang, Chao Li, Fan Li, Zizheng Cao and Eduward Tangdiongga
Photonics 2023, 10(7), 815; https://doi.org/10.3390/photonics10070815 - 13 Jul 2023
Cited by 2 | Viewed by 1102
Abstract
The predominant focus of research in high-speed optical wireless communication (OWC) lies in line-of-sight (LOS) links with narrow infrared beams. However, the implementation of precise tracking and steering necessitates delicate active devices, thereby presenting a formidable challenge in establishing a cost-effective wireless transmission. [...] Read more.
The predominant focus of research in high-speed optical wireless communication (OWC) lies in line-of-sight (LOS) links with narrow infrared beams. However, the implementation of precise tracking and steering necessitates delicate active devices, thereby presenting a formidable challenge in establishing a cost-effective wireless transmission. Other than using none-line-of-sight (NLOS) links with excessive link losses and multi-path distortions, the simplification of the tracking and steering process can be alternatively achieved through the utilization of divergent optical beams in LOS. This paper addresses the issue by relaxing the stringent link budget associated with divergent Gaussian-shaped optical beams and narrow field-of-view (FOV) receivers in LOS OWC through the independent optimization of geometrical path loss and fiber coupling loss. More importantly, the geometrical path loss is effectively mitigated by modifying the transverse intensity distribution of the optical beam using manipulations of multi-mode fibers (MMFs) in an all-fiber configuration. In addition, the sufficiently excited higher order modes (HOMs) of MMFs enable a homogenized distribution of received optical powers (ROPs) within the coverage area, which facilitates the mobility of end-users. Comparative analysis against back-to-back links without free-space transmission demonstrates the proposed scheme’s ability to achieve low power penalties. With the minimized link losses, experimental results demonstrate a 10 Gbps error-free (BER < 10−13) LOS OWC downlink transmission at 2.5 m over an angular range of 10° × 10° without using any optical pre-amplifications at a typical PIN receiver. The proposed scheme provides a simple and low-cost solution for high-speed and short-range indoor wireless applications. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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24 pages, 11849 KiB  
Article
High-Speed Underwater Optical Wireless Communication with Advanced Signal Processing Methods Survey
by Chengwei Fang, Shuo Li, Yinong Wang and Ke Wang
Photonics 2023, 10(7), 811; https://doi.org/10.3390/photonics10070811 - 12 Jul 2023
Cited by 8 | Viewed by 2189
Abstract
Underwater wireless communication (UWC) technology has attracted widespread attention in the past few years. Compared with conventional acoustic underwater wireless communication technology, underwater optical wireless communication (UOWC) technology has promising potential to provide high data rate wireless connections due to the large license-free [...] Read more.
Underwater wireless communication (UWC) technology has attracted widespread attention in the past few years. Compared with conventional acoustic underwater wireless communication technology, underwater optical wireless communication (UOWC) technology has promising potential to provide high data rate wireless connections due to the large license-free bandwidth. Building a high-performance and reliable UOWC system has become the target of researchers and various advanced and innovative technologies have been proposed and investigated. Among them, better hardware such as transmitters and receivers, as well as more advanced modulation and signal processing techniques, are key factors in improving UOWC system performance. In this paper, we review the recent development in UOWC systems. In particular, we provide a brief introduction to different types of UOWC systems based on channel configuration, and we focus on various recent studies on advanced signal processing methods in UOWC systems, including both traditional non-machine learning (NML) equalizers and machine learning (ML) schemes based on neural networks. In addition, we also discuss the key challenges in UOWC systems for future applications. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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19 pages, 4729 KiB  
Article
Indoor Visible-Light 3D Positioning System Based on GRU Neural Network
by Wuju Yang, Ling Qin, Xiaoli Hu and Desheng Zhao
Photonics 2023, 10(6), 633; https://doi.org/10.3390/photonics10060633 - 31 May 2023
Cited by 4 | Viewed by 1235
Abstract
With the continuous development of artificial intelligence technology, visible-light positioning (VLP) based on machine learning and deep learning algorithms has become a research hotspot for indoor positioning technology. To improve the accuracy of robot positioning, we established a three-dimensional (3D) positioning system of [...] Read more.
With the continuous development of artificial intelligence technology, visible-light positioning (VLP) based on machine learning and deep learning algorithms has become a research hotspot for indoor positioning technology. To improve the accuracy of robot positioning, we established a three-dimensional (3D) positioning system of visible-light consisting of two LED lights and three photodetectors. In this system, three photodetectors are located on the robot’s head. We considered the impact of line-of-sight (LOS) and non-line-of-sight (NLOS) links on the received signals and used gated recurrent unit (GRU) neural networks to deal with nonlinearity in the system. To address the problem of poor stability during GRU network training, we used a learning rate attenuation strategy to improve the performance of the GRU network. The simulation results showed that the average positioning error of the system was 2.69 cm in a space of 4 m × 4 m × 3 m when only LOS links were considered and 2.66 cm when both LOS and NLOS links were considered with 95% of the positioning errors within 7.88 cm. For two-dimensional (2D) positioning with a fixed positioning height, 80% of the positioning error was within 9.87 cm. This showed that the system had a high anti-interference ability, could achieve centimeter-level positioning accuracy, and met the requirements of robot indoor positioning. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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13 pages, 454 KiB  
Article
Asymptotic Capacity Maximization for MISO Visible Light Communication Systems with a Liquid Crystal RIS-Based Receiver
by Qi Wu, Jian Zhang, Yanyu Zhang, Gang Xin and Dongqin Guo
Photonics 2023, 10(2), 128; https://doi.org/10.3390/photonics10020128 - 27 Jan 2023
Cited by 3 | Viewed by 1214
Abstract
Combined with reconfigurable intelligent surfaces (RISs), visible light communications (VLCs) can increase the communication performance to a great degree. However, the research into RIS-aided VLC systems has mainly focused on mirror array-based RISs deployed on the wall while neglecting liquid crystal (LC)-based RISs [...] Read more.
Combined with reconfigurable intelligent surfaces (RISs), visible light communications (VLCs) can increase the communication performance to a great degree. However, the research into RIS-aided VLC systems has mainly focused on mirror array-based RISs deployed on the wall while neglecting liquid crystal (LC)-based RISs in VLC receivers. With the development of advanced materials, the LC RIS has been gradually attracting attention from researchers. Inspired by the current research into the LC RIS, the applications of the LC RIS in multiple-input single-output (MISO) VLC systems are investigated in this paper. We formulate an optimization problem with asymptotic capacity maximization as the objective function and the refractive index of the LC RIS as the independent variable. As for this nonconvex optimization problem, we propose the particle swarm optimization (PSO) algorithm to determine the configuration of parameters for the LC RIS. The simulation results indicate that the employment of the LC RIS in VLC receivers can raise the communication performance of the MISO-VLC systems; meanwhile, the proposed algorithm is an effective way to deal with the optimization problems for LC RIS-based MISO-VLC systems when compared with the exhaustive search method and a baseline scheme. The LC RIS is also expected to solve the dead zone problem in traditional VLC systems. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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16 pages, 2735 KiB  
Article
DeepGOMIMO: Deep Learning-Aided Generalized Optical MIMO with CSI-Free Detection
by Xin Zhong, Chen Chen, Shu Fu, Zhihong Zeng and Min Liu
Photonics 2022, 9(12), 940; https://doi.org/10.3390/photonics9120940 - 05 Dec 2022
Cited by 2 | Viewed by 1297
Abstract
Generalized optical multiple-input multiple-output (GOMIMO) techniques have been recently shown to be promising for high-speed optical wireless communication (OWC) systems. In this paper, we propose a novel deep learning-aided GOMIMO (DeepGOMIMO) framework for GOMIMO systems, wherein channel state information (CSI)-free detection can be [...] Read more.
Generalized optical multiple-input multiple-output (GOMIMO) techniques have been recently shown to be promising for high-speed optical wireless communication (OWC) systems. In this paper, we propose a novel deep learning-aided GOMIMO (DeepGOMIMO) framework for GOMIMO systems, wherein channel state information (CSI)-free detection can be enabled by employing a specially designed deep neural network (DNN)-based MIMO detector. The CSI-free DNN detector mainly consists of two modules: one is the preprocessing module, which is designed to address both the path loss and channel crosstalk issues caused by MIMO transmission, and the other is the feedforward DNN module, which is used for joint detection of spatial and constellation information by learning the statistics of both the input signal and the additive noise. Our simulation results clearly verify that, in a typical indoor 4 × 4 MIMO-OWC system using both generalized optical spatial modulation (GOSM) and generalized optical spatial multiplexing (GOSMP) with unipolar nonzero 4-level pulse-amplitude modulation (4-PAM) modulation, the proposed CSI-free DNN detector achieves near the same bit error rate (BER) performance as the optimal joint maximum-likelihood (ML) detector, but with much-reduced computational complexity. Moreover, because the CSI-free DNN detector does not require instantaneous channel estimation to obtain accurate CSI, it enjoys the unique advantages of improved achievable data rate and reduced communication time delay in comparison to the CSI-based zero-forcing DNN (ZF-DNN) detector. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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17 pages, 5635 KiB  
Article
An Experimental and Numerical Study of the Impact of Ambient Light of SiPMs in VLC Receivers
by William Matthews and Steve Collins
Photonics 2022, 9(12), 888; https://doi.org/10.3390/photonics9120888 - 22 Nov 2022
Cited by 2 | Viewed by 1558
Abstract
Silicon photomultiplier’s relatively large area and ability to detect single photons makes them attractive as receivers for visible light communications. However, their non-linear response has a negative impact on the receiver performance, including making them particularly sensitive to ambient light. Experiments and Monte [...] Read more.
Silicon photomultiplier’s relatively large area and ability to detect single photons makes them attractive as receivers for visible light communications. However, their non-linear response has a negative impact on the receiver performance, including making them particularly sensitive to ambient light. Experiments and Monte Carlo simulations have been used to study this non-linearity. The resulting detailed understanding of the origins of the non-linear response leads to concerns over the accuracy of some previous simulations of SiPMs. In addition, it leads to simple methods to determine the maximum rate at which an SiPM can count photons and of determining the impact of a SiPMs non-linearity on its performance of a receiver. Finally, a method of determining which filters should be used to protect an SiPM from ambient light is proposed. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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14 pages, 6218 KiB  
Article
Synchronous Clock Recovery of Photon-Counting Underwater Optical Wireless Communication Based on Deep Learning
by Haodong Yang, Qiurong Yan, Ming Wang, Yuhao Wang, Peng Li and Wei Wang
Photonics 2022, 9(11), 884; https://doi.org/10.3390/photonics9110884 - 21 Nov 2022
Cited by 4 | Viewed by 1510
Abstract
In photon-counting underwater optical wireless communication (UOWC), the recovery of the time slot synchronous clock is extremely important, and it is the basis of symbol synchronization and frame synchronization. We have previously proposed a time slot synchronous clock extraction method based on single [...] Read more.
In photon-counting underwater optical wireless communication (UOWC), the recovery of the time slot synchronous clock is extremely important, and it is the basis of symbol synchronization and frame synchronization. We have previously proposed a time slot synchronous clock extraction method based on single photon pulse counting, but the accuracy needs to be further improved. Deep learning is very effective for feature extraction; synchronous information is already implicit in the discrete single photon pulse signal output by single photon avalanche diode (SPAD), which is used as a communication receiver. Aiming at this characteristic, a method of time slot synchronous clock recovery for photon-counting UOWC based on deep learning is proposed in this paper. Based on the establishment of the underwater channel model and SPAD receiver model, the Monte Carlo method is used to generate discrete single photon pulse sequences carrying synchronous information, which are used as training data. Two neural network models based on regression problem and classification problem are designed to predict the phase value of the time slot synchronous clock. Experimental results show that when the average number of photons per time slot is eight, photon-counting UOWC with a data rate of 1Mbps and a bit error rate (BER) of 5.35 × 10−4 can be achieved. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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14 pages, 381 KiB  
Article
Reconstructed Hybrid Optical OFDM-NOMA for Multiuser VLC Systems
by Baolong Li, Jianfeng Shi and Simeng Feng
Photonics 2022, 9(11), 857; https://doi.org/10.3390/photonics9110857 - 13 Nov 2022
Cited by 4 | Viewed by 1436
Abstract
Non-orthogonal multiple access (NOMA) is deemed to be a prospective multiple access technology of the next generation. However, in visible light communication (VLC), when advanced hybrid optical orthogonal frequency division multiplexing (O-OFDM), such as hybrid asymmetrically clipped O-OFDM (HACO-OFDM), is combined with NOMA, [...] Read more.
Non-orthogonal multiple access (NOMA) is deemed to be a prospective multiple access technology of the next generation. However, in visible light communication (VLC), when advanced hybrid optical orthogonal frequency division multiplexing (O-OFDM), such as hybrid asymmetrically clipped O-OFDM (HACO-OFDM), is combined with NOMA, error propagation is induced, which degrades the system performance. Therefore, a novel reconstructed hybrid O-OFDM-NOMA (RHO-OFDM-NOMA) scheme is conceived in this paper. In order to eliminate the error propagation, the users in RHO-OFDM-NOMA opt for the ACO-OFDM or clipping-free O-OFDM signals according to their channel qualities, which are subsequently superimposed on pulse-amplitude-modulated discrete multitone (PAM-DMT) to yield the spectrum-efficient hybrid O-OFDM signal. Furthermore, a reconstruction process is designed to ensure the non-negativity. Compared with HACO-OFDM, the proposed RHO-OFDM can retain the error propagation in NOMA-VLC, whilst maintaining the superiorities of high spectral and power efficiency. It is demonstrated by simulation results that RHO-OFDM-NOMA can support a notably higher data rate than the NOMA schemes using conventional O-OFDM. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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17 pages, 1777 KiB  
Article
On the Optimisation of Illumination LEDs for VLP Systems
by José Miguel Menéndez and Heidi Steendam
Photonics 2022, 9(10), 750; https://doi.org/10.3390/photonics9100750 - 10 Oct 2022
Cited by 1 | Viewed by 1415
Abstract
Recent studies have explored the synergy of illumination and positioning using indoor lighting infrastructure. While these studies mainly focused on the analysis of the performance of visible light positioning, these works did not consider the illumination aspects of such combined systems. In this [...] Read more.
Recent studies have explored the synergy of illumination and positioning using indoor lighting infrastructure. While these studies mainly focused on the analysis of the performance of visible light positioning, these works did not consider the illumination aspects of such combined systems. In this paper, we analyse the illumination aspects based on the main illumination characteristics defined in the European Standard EN 12464-1, i.e., the horizontal illuminance and the uniformity of illuminance. As in the standard, we distinguish between a task area, where visual activities are performed that demand higher illuminance and uniformity, and a surrounding area that borders the former. In our analysis, we derive simple rules of thumb to determine the number and placement of LEDs to satisfy the constraints on the horizontal illuminance and uniformity for a given area. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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11 pages, 3015 KiB  
Article
Long-Distance, Real-Time LED Display-Camera Communication System Based on LED Point Clustering and Lightweight Image Processing
by Jingwen Li, Chuhan Pan, Junxing Pan, Jiajun Lin, Mingli Lu, Zoe Lin Jiang and Junbin Fang
Photonics 2022, 9(10), 721; https://doi.org/10.3390/photonics9100721 - 03 Oct 2022
Viewed by 1465
Abstract
LED displays can be used to realize the dual functions of display and communication simultaneously. However, existing LED display-based visible light communication (VLC) systems suffer due to their short transmission distance and are not practical. A long-distance, real-time display-camera communication (DCC) system is [...] Read more.
LED displays can be used to realize the dual functions of display and communication simultaneously. However, existing LED display-based visible light communication (VLC) systems suffer due to their short transmission distance and are not practical. A long-distance, real-time display-camera communication (DCC) system is proposed in this paper. First, a LED-DCC point clustering scheme is proposed to increase the transmission distance by clustering multiple adjacent LED display points for improving the quality of the VLC signal captured by an image sensor. Then, a lightweight, back-forth, fast image processing algorithm is proposed to reduce the introduced additional computational complexity caused by point clustering and enhance the reliability of information extraction from the real-time captured images/video frames. The experimental system was implemented with a 2.2-inch 16 × 16 point LED display and the CMOS camera on the smartphone. Experimental results show that the proposed system can achieve a maximum data transmission distance of 7 m under a bit error rate (BER) of 0.5, which is about 9 times that of the previous LED-DCC system, and can achieve a data transmission distance of 175 cm under the 7% forward error correction (FEC) limit, which is about 12 times that of the previous LED-DCC system. Additionally, the decoding latency for extracting information from each video frame is only 13.26 ms, which guarantees real-time data reception. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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25 pages, 2934 KiB  
Article
Decoding-Order-Based Power Allocation (DOPA) Scheme for Non-Orthogonal Multiple Access (NOMA) Visible Light Communication Systems
by Ali H. Alqahtani, Esam M. Almohimmah, Mohammed T. Alresheedi, Ahmad Fauzi Abas, Ahmad-Adnan Qidan and Jaafar Elmirghani
Photonics 2022, 9(10), 718; https://doi.org/10.3390/photonics9100718 - 02 Oct 2022
Cited by 2 | Viewed by 1869
Abstract
Non-orthogonal multiple access (NOMA) is an effective multiple access scheme that can be used to improve considerably the spectral efficiency of indoor downlink visible light communication (VLC) systems. However, NOMA suffers from inevitable multi-user interference which degrades the system performance. In this paper, [...] Read more.
Non-orthogonal multiple access (NOMA) is an effective multiple access scheme that can be used to improve considerably the spectral efficiency of indoor downlink visible light communication (VLC) systems. However, NOMA suffers from inevitable multi-user interference which degrades the system performance. In this paper, a NOMA scheme is applied in a downlink VLC system and the impact of the multi-user interference on the system performance is studied. A closed-form expression for the user symbol error rate (SER) is derived and a decoding-order-based power allocation (DOPA) method is proposed to reduce the multi-user interference and find the optimal power allocation that minimizes the SER. The significance of the proposed schemes is demonstrated by simulation. The results show that the proposed DOPA method is able to reduce effectively the multi-user interference and provide more sum rate in comparison with benchmarking schemes such as the gain ratio PA (GRPA) and the normalized gain difference PA (NGDPA) methods. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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12 pages, 3120 KiB  
Communication
CGA-VLP: High Accuracy Visible Light Positioning Algorithm Using Single Square LED with Geomagnetic Angle Correction
by Chen Yang, Shangsheng Wen, Danlan Yuan, Junye Chen, Junlin Huang and Weipeng Guan
Photonics 2022, 9(9), 653; https://doi.org/10.3390/photonics9090653 - 14 Sep 2022
Cited by 8 | Viewed by 1854
Abstract
Visible light positioning (VLP), benefiting from its high accuracy and low cost, is a promising technology for indoor location-based services. In this article, the theoretical limits and error sources of traditional camera-based VLP systems are analyzed. To solve the problem that multiple LEDs [...] Read more.
Visible light positioning (VLP), benefiting from its high accuracy and low cost, is a promising technology for indoor location-based services. In this article, the theoretical limits and error sources of traditional camera-based VLP systems are analyzed. To solve the problem that multiple LEDs are required and auxiliary sensors are imperfect, a VLP system with a single square LED which can correct the geomagnetic angle obtained from a geomagnetic sensor is proposed. In addition, we conducted a static positioning experiment and a dynamic positioning experiment integrated with pedestrian dead reckoning on an Android platform to evaluate the effectiveness of the proposed method. According to the experimental results, when the horizontal distance between the camera and the center of the LED is less than 120 cm, the average positioning error can be retained within 10 cm and the average positioning time on the mobile phone is 39.64 ms. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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13 pages, 3539 KiB  
Article
Performance Estimation and Selection Guideline of SiPM Chip within SiPM-Based OFDM-OWC System
by Long Zhang, Rui Jiang, Xinke Tang, Zhen Chen, Zhongyi Li and Juan Chen
Photonics 2022, 9(9), 637; https://doi.org/10.3390/photonics9090637 - 05 Sep 2022
Cited by 3 | Viewed by 1671
Abstract
The orthogonal frequency division multiplexing (OFDM), which has high spectral efficiency, is an attractive solution for silicon photomultiplier (SiPM)-based optical wireless communication (OWC) systems to boost data rates. However, the currently available SiPMs are not optimized for implementing the OFDM receiver. Incorporating different [...] Read more.
The orthogonal frequency division multiplexing (OFDM), which has high spectral efficiency, is an attractive solution for silicon photomultiplier (SiPM)-based optical wireless communication (OWC) systems to boost data rates. However, the currently available SiPMs are not optimized for implementing the OFDM receiver. Incorporating different types of SiPM at the OFDM receiver results in different data rates at the same condition. Therefore, the receiver designer requires a method for predicting the performance of SiPMs and then selects the best one to build the optimum receiver. In this paper, we first investigate the origin of SiPM’s power-dependent frequency response. The investigation outcome is then used to create a method for predicting the subcarrier SNR. Combining the estimated subcarrier SNR with the bit-loading scheme, we finally propose a general approach for estimating the fundamental OFDM data rate an SiPM chip can support at a given received power. Results are then presented that can be used by the future receiver designer as a guideline to find the best type of SiPM to build the optimum OFDM receiver. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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Review

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24 pages, 1846 KiB  
Review
Visible Light Communications: A Survey on Recent High-Capacity Demonstrations and Digital Modulation Techniques
by Pedro A. Loureiro, Fernando P. Guiomar and Paulo P. Monteiro
Photonics 2023, 10(9), 993; https://doi.org/10.3390/photonics10090993 - 30 Aug 2023
Cited by 3 | Viewed by 1561
Abstract
In order to deal with the increasing number of mobile devices and with their demand for Internet services, particularly social media platforms, streaming video, and online gaming, Radio-Frequency (RF) wireless networks have been pushed to their capacity limits. In addition to this, 80% [...] Read more.
In order to deal with the increasing number of mobile devices and with their demand for Internet services, particularly social media platforms, streaming video, and online gaming, Radio-Frequency (RF) wireless networks have been pushed to their capacity limits. In addition to this, 80% of the total data traffic is carried out by users inside buildings. Therefore, new technologies have started to be considered for indoor wireless communications. Visible Light Communications (VLC) can provide both illumination and communications, appearing as an alternative or complement to RF wireless networks. VLC offers high bandwidth and immunity to interference from electromagnetic sources. This manuscript reviews recent high-capacity VLC demonstrations. The main focus of this work is to present digital-signal-processing techniques used in VLC systems. Different modulation formats are analyzed, which can be divided into two large groups, namely single-carrier and multi-carrier modulation schemes. Finally, some recently proposed capacity-achieving strategies are presented. We discuss how to implement these techniques and how they will be useful for the continued development of VLC systems. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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21 pages, 9221 KiB  
Review
A Review of Advanced Transceiver Technologies in Visible Light Communications
by Cuiwei He and Chen Chen
Photonics 2023, 10(6), 648; https://doi.org/10.3390/photonics10060648 - 03 Jun 2023
Cited by 1 | Viewed by 1902
Abstract
Visible Light Communication (VLC) is an emerging technology that utilizes light-emitting diodes (LEDs) for both indoor illumination and wireless communications. It has the potential to enhance the existing WiFi network and connect a large number of high-speed internet users in future smart home [...] Read more.
Visible Light Communication (VLC) is an emerging technology that utilizes light-emitting diodes (LEDs) for both indoor illumination and wireless communications. It has the potential to enhance the existing WiFi network and connect a large number of high-speed internet users in future smart home environments. Over the past two decades, VLC techniques have made significant strides, resulting in transmission data rates increasing from just a few Mbps to several tens of Gbps. These achievements can be attributed to the development of various transceiver technologies. At the transmitter, LEDs should provide high-quality light for illumination and support wide modulation bandwidths. Meanwhile, at the receiver, optics systems should have functions such as optical filtering, light concentration, and, ideally, a wide field of view (FOV). The photodetector must efficiently convert the optical signal into an electrical signal. Different VLC systems typically consider various transceiver designs. In this paper, we provide a survey of some important emerging technologies used to create advanced optical transceivers in VLC. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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25 pages, 7076 KiB  
Review
A Review on Image Sensor Communication and Its Applications to Vehicles
by Ruiyi Huang and Takaya Yamazato
Photonics 2023, 10(6), 617; https://doi.org/10.3390/photonics10060617 - 26 May 2023
Cited by 3 | Viewed by 1534
Abstract
Image sensor communication (ISC), also known as optical camera communication, is a form of visible light communication that utilizes image sensors rather than a single photodiode, for data reception. ISC offers spatial separation properties and robustness to ambient noise, making it suitable for [...] Read more.
Image sensor communication (ISC), also known as optical camera communication, is a form of visible light communication that utilizes image sensors rather than a single photodiode, for data reception. ISC offers spatial separation properties and robustness to ambient noise, making it suitable for outdoor applications such as intelligent transportation systems (ITSs). This review analyzes the research trends in ISC, specifically concerning its application in ITSs. Our focus is on various ISC receivers, including rolling shutter cameras, global shutter high-speed cameras, optical communication image sensors, and event cameras. We analyze how each of these receivers is being utilized in ISC vehicular applications. In addition, we highlight the use of ISC in range estimation techniques and the ability to achieve simultaneous communication and range estimation. By examining these topics, we aim to provide a comprehensive overview of the role of ISC technology in ITSs and its potential for future development. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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11 pages, 2048 KiB  
Review
Recent Advances in Optical Injection Locking for Visible Light Communication Applications
by Xingchen Liu, Junhui Hu, Qijun Bian, Shulan Yi, Yingnan Ma, Jianyang Shi, Ziwei Li, Junwen Zhang, Nan Chi and Chao Shen
Photonics 2023, 10(3), 291; https://doi.org/10.3390/photonics10030291 - 10 Mar 2023
Cited by 2 | Viewed by 2860
Abstract
The introduction of visible light communication (VLC) technology could increase the capacity of existing wireless communication systems towards 6G networks. In practice, VLC can make good use of lighting system infrastructures to transmit data using light fidelity (Li-Fi). The use of semiconductor light [...] Read more.
The introduction of visible light communication (VLC) technology could increase the capacity of existing wireless communication systems towards 6G networks. In practice, VLC can make good use of lighting system infrastructures to transmit data using light fidelity (Li-Fi). The use of semiconductor light sources, including light-emitting diodes (LEDs) and laser diodes (LDs) are essential to VLC technology because these devices are energy-efficient and have long lifespans. To achieve high-speed VLC links, various technologies have been utilized, including injection locking. Optical injection locking (OIL) is an optical frequency and phase synchronization technique that has been implemented in semiconductor laser systems for performance enhancement. High-performance optoelectronic devices with narrow linewidth, wide tunable emission, large modulation bandwidth and high data transmission rates are desired for advanced VLC. Thus, the features of OIL could be promising for building high-performance VLC systems. In this paper, we present a comprehensive review of the implementation of the injection-locking technique in optical communication systems. The enhancement of characteristics through OIL is elucidated. The applications of OIL in VLC systems are discussed. The prospects of OIL for future VLC systems are evaluated. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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17 pages, 1491 KiB  
Review
Advances in Visible Light Communication Technologies and Applications
by Zuhang Geng, Faisal Nadeem Khan, Xun Guan and Yuhan Dong
Photonics 2022, 9(12), 893; https://doi.org/10.3390/photonics9120893 - 23 Nov 2022
Cited by 10 | Viewed by 3515
Abstract
With the development of light emitting diode (LED) lighting technology and its wide applications, visible light communication (VLC) technology has also seen significant advancements. VLC is regarded as a supplementary technology to radio frequency (RF) due to its unregulated spectrum and extraordinarily high [...] Read more.
With the development of light emitting diode (LED) lighting technology and its wide applications, visible light communication (VLC) technology has also seen significant advancements. VLC is regarded as a supplementary technology to radio frequency (RF) due to its unregulated spectrum and extraordinarily high communication rates. In this paper, the advantages, architectures, key technologies, application scenarios and machine learning (ML) applications of VLC are reviewed and summarized. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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29 pages, 3831 KiB  
Review
AI-Enabled Intelligent Visible Light Communications: Challenges, Progress, and Future
by Jianyang Shi, Wenqing Niu, Yinaer Ha, Zengyi Xu, Ziwei Li, Shaohua Yu and Nan Chi
Photonics 2022, 9(8), 529; https://doi.org/10.3390/photonics9080529 - 29 Jul 2022
Cited by 17 | Viewed by 3425
Abstract
Visible light communication (VLC) is a highly promising complement to conventional wireless communication for local-area networking in future 6G. However, the extra electro-optical and photoelectric conversions in VLC systems usually introduce exceeding complexity to communication channels, in particular severe nonlinearities. Artificial intelligence (AI) [...] Read more.
Visible light communication (VLC) is a highly promising complement to conventional wireless communication for local-area networking in future 6G. However, the extra electro-optical and photoelectric conversions in VLC systems usually introduce exceeding complexity to communication channels, in particular severe nonlinearities. Artificial intelligence (AI) techniques are investigated to overcome the unique challenges in VLC, whereas considerable obstacles are found in practical VLC systems applied with intelligent learning approaches. In this paper, we present a comprehensive study of the intelligent physical and network layer technologies for AI-empowered intelligent VLC (IVLC). We first depict a full model of the visible light channel and discuss its main challenges. The advantages and disadvantages of machine learning in VLC are discussed and analyzed by simulation. We then present a detailed overview of advances in intelligent physical layers, including optimal coding, channel emulator, MIMO, channel equalization, and optimal decision. Finally, we envision the prospects of IVLC in both the intelligent physical and network layers. This article lays out a roadmap for developing machine learning-based intelligent visible light communication in 6G. Full article
(This article belongs to the Special Issue Advances in Visible Light Communication)
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