An Integrated Visible-Light Communication/Gesture-Recognition System Enabled by Machine Learning

Driven by the increase in Internet of Things (IoT) devices for smart home technologies, visible light communications (VLC) using multiple light emitting diodes (LEDs) have been attracting much attention in order to cope with depleted radio frequency spectrum. This paper presents a suboptimal LED selection algorithm for distributed multiple-input multiple-output (D-MIMO) VLC systems. When total ceiling LEDs are turned on to send information while illuminating an indoor environment, the problems of low energy efficiency and mutual interference between VLC channels arise. The proposed algorithm begins by selecting the LED associated with the largest VLC channel gain and adds the LED supporting the largest level of uncorrelation with the maximum VLC channel gain in each step. Simulation results showed that the proposed scheme achieves a capacity similar to an optimal selection algorithm with reduced computational complexity. With a larger distance between the light terminals and a shorter distance between the LEDs, better channel capacity performance of the proposed scheme can be achieved.

Visible light communication (VLC) has emerged as a viable complement to traditional radio frequency (RF) based systems and as an enabler for high data rate communications for beyond-5G (B5G) indoor communication systems. In particular, the emergence of new B5G-based applications with quality of service (QoS) requirements and massive connectivity has recently led to research on the required service-levels and the development of improved physical (PHY) layer methods. As part of recent VLC standards development activities, the IEEE has formed the 802.11bb “Light Communications (LC) for Wireless Local Area Networking” standardization group. This paper investigates the network requirements of 5G indoor services such as virtual reality (VR) and high-definition (HD) video for residential environments using VLC. In this paper, we consider such typical VLC scenarios with additional impairments such as light-emitting diode (LED) nonlinearity and imperfect channel feedback, and propose hyperparameter-free mitigation techniques using Reproducing Kernel Hilbert Space (RKHS) methods. In this context, we also propose using a direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM)-based adaptive VLC transmission method that uses precomputed bit error rate (BER) expressions for these RKHS-based detection methods and performs adaptive BER-based modulation-order switching. Simulations of channel impulse responses (CIRs) show that the adaptive transmission method provides significantly improved error rate performance, which makes it promising for high data rate VLC-based 5G indoor services.

Optical wireless communication (OWC) is gaining momentum as a key enabler for next-generation indoor Internet of Things (IoT) systems, offering high-bandwidth, low-latency, and interference-free connectivity by leveraging its inherent line-of-sight nature. Its versatility makes it attractive for a wide range of dynamic applications, including flexible interconnects in data centers, high-speed data delivery to mobile devices, and communication with cooperative robots. However, conventional solutions still face critical challenges. Visible light communication and positioning (VLCP) is constrained by limited modulation bandwidth and a trade-off between localization precision and data rate, while laser-based OWC systems often suffer from alignment sensitivity, making them less effective in dynamic or mobile scenarios. To overcome these barriers, we present a dynamic localization and two-dimensional (2D) beam scanning communication system based on a single tunable MEMS vertical-cavity surface-emitting laser (MEMS-VCSEL) integrated with a corner cube reflector (CCR). This compact, coaxial optical architecture enables precise real-time tracking and continuous beam alignment without relying on external sensors. A Search-and-Communicate mechanism facilitates autonomous target acquisition and link maintenance. Experimental validation demonstrates sub-3 mm tracking error, stable communication over a 3-meter communication link achieving data rates up to 3.4 Gbps-while the target is in motion.

Visible Light Communication (VLC) has emerged as an attractive alternative to radio frequency (RF) communication, due to cost-effectiveness and being license free. It has also proved its applicability in automotive applications, as an alternative and/or a complement to the traditional RF-based communications. We investigate the suitability of VLC in Intelligent Transportation Systems (ITS) and discuss its advantages in terms of safety enhancement and improved efficiency of the ITS. In this thesis, a VLC-based Vehicle-to-Vehicle (V2V) system in practical environments, considering both Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) paths are presented. The thesis investigates robust communication between a Light Emitting Diodes (LEDs) based VLC emitter and Photodiodes (PDs) based VLC receiver. For consideration of a V2V communication system, we consider transmitter on vehicle headlights and receivers on taillight making 2 _ 2 Multiple-Input-Multiple-Output (MIMO) communication link. A closed-form expression of the Channel Impulse Response (CIR) is derived and the effect of various channel parameters is analyzed. Optical-Orthogonal Frequency Division Multiplexing (O-OFDM) with adaptive modulation schemes is proposed for system improvement. Its performance is evaluated in terms of Inter Symbol Interference (ISI) mitigation, and data rate improvement. Moreover, the effect of sunlight on the V2V-VLC Two denoising schemes are proposed and evaluated as a solution to combat the effect of the solar irradiance on the VLC signal. Firstly, we use a differential receiver for denoising purposes followed by k-Nearest Neighbour (kNN) based adaptive _ltering algorithm, which is a supervised Machine Learning (MLE) technique. The shadowing effect is also studied. Moreover, an application of VLC in Foglet based ITS is described. The simulation validation of the VLC-based V2V system is performed under various environmental conditions and scenarios. Obtained results emphasize the suitability of VLC technology for automobile applications,.

Visible light communication (VLC) offers the opportunity to provide services with new requirements, when compared to the ones offered so far by radio wireless technologies almost exclusively. The idea behind VLC is to re-use the light signal, currently utilized for illumination purposes only, to transfer information wirelessly. Light-emitting diodes (LEDs), which are the natural sources of light for VLC due to their fast time response and high energy-efficiency, are devices with a notable non-linear response. A current trend to improve the achievable data rate of the VLC links relies on the use of linear waveforms, instead of just using On-Off Keying, which is robust against LED non-linearities but difficult to adapt to the variable VLC link conditions. Since having a linear transfer function is important when using efficient waveforms such as orthogonal frequency division multiplexing (OFDM), this paper starts by modelling the voltage-versus-current response of commercial LEDs. Then, the derived model is used to identify the guidelines that new VLC prototypes should fulfill. In particular, this paper focuses on the strength of the communication signal, compared to the light source optical power, and shows the way in which these parameters affect the coverage range of a multi-cell VLC system. The effect that these key design parameters have on the VLC link are identified, based on a real experimental setting, as they are difficult to model accurately due to the complex non-linear nature of LEDs when working in highly energy-efficient regimes.

This paper investigates the effect of light emitting diodes (LEDs) positioning and allocation in the channel analysis performance for an indoor intra-vehicle visible light communication (VLC) system. The MATLAB simulation results focus on the received power and the signal to noise ratio (SNR) within a sports utility vehicle. Furthermore, this work aims to validate by investigating two different scenarios, one utilizing two sources of power and the other using three sources of power with various locations, how LED’s spatial positioning affects the VLC system and the probability of error. Proving the demand for considering LEDs layout positioning while designing a VLC system.

Advances in high brightness light emitting diode (LED) technology are enabling myriad applications in lighting including visible light communications (VLC) technology that has the potential to complement RF technology to provide wireless data access for indoor coverage. This chapter reviews various dimming techniques suitable for VLC, and presents an LED driver circuit architecture incorporating digitally controlled analog circuit blocks to deliver concurrent dimming control and data transmission for VLC-enabled lighting. To achieve this target, a bi-level pulse-width modulation (PWM) driving scheme is applied to enable data transmission during the “off” period of the LED drive current while concurrently providing dimming control. The proposed architecture is compatible with digital baseband modulation schemes and implements a mechanism for ease of integration with commercial off-the-shelf (COTS) LED drivers for VLC system realization. This chapter also discusses a dimming compatible analog baseband modulation scheme. The reverse polarity optical orthogonal frequency-division multiplexing (RPO-OFDM) is a recent approach to realize compatibility between any format of an analog OFDM signal suitable for optical transmission and the concept of a digital pulse-width modulation (PWM) technique for dimming control. We also describe an implementation of the RPO-OFDM approach as part of a wireless access testbed. Experiments reveal that bit-error and bit-rate performances are maintained over a wide range of dimming.

Visible light communication (VLC) reuses illumination devices, particularly light-emitting diodes (LEDs), for communication purposes. It has great potential to alleviate the strain on radio-frequency spectrum in indoor environments. VLC-enabled LED luminaries form VLC attocells that carry downlink data traffic to indoor mobile or stationary terminals. While one of the advantages of indoor VLC is low interference due to natural cell boundaries such as walls, multiple VLC attocells within a room would interfere. This is because illumination requirements often mandate a rich overlap of emissions of luminaries in a room. In this paper, we suggest the coordination of multiple VLC attocells (i.e., VLC-enabled LED luminaries) to turn the problem of overlap and thus interference into an advantage. We stipulate that this coordination can be accomplished through power line communication, which has been considered before as a means to transport data to VLC transmitters. Borrowing from concepts developed for radio-frequency wireless communications, we develop several precoding schemes for the new coordinated VLC broadcasting architecture. These include designs for the case of imperfect channel knowledge at the VLC transmitter, since channel information is usually provided through a low-rate feedback channel. The performance advantages for VLC transmission due to the proposed coordination and precoding designs are demonstrated based on a set of numerical results.

This paper proposes a novel code length optimization for improving the throughput performance on Orthogonal Frequency Division Multiple - Interleave Division Multiple Access (OFDM-IDMA) based Visible Light Communication (VLC). VLC is under the global spotlight, since Light Emitting Diode (LED) has recently become a part of building infrastructure and VLC functionality is fairly easy by adding communication components to LED lighting. To enhance the VLC capability, OFDM-IDMA has been proposed as a connection method in a multiuser environment. By applying an interleave pattern peculiar to the transmission signal of each user, signals are well separated and multiple access becomes possible in VLC-OFDM-IDMA. However, VLC-OFDM-IDMA necessitates a low coding rate error correction code as well as a long length spreading code which limits the throughput performance. To resolve this problem, we newly introduce a channel ranking and allocates the short length spreading code to a user in good channel state. Overall throughput performance can be improved while the compatible BER performance.

이 논문에서는 LED(Light Emitting Diode) 조명을 이용한 간편한 가시광 통신 시스템을 구현하기 위해, 비 캐리어 NRZ-OOK(non-return to zero on off keying) 변조 방식을 사용하고, 가시광 송신을 위한 발광소자인 <TEX>$3{\times}3$</TEX> 백색 LED 배열과 가시광 수신을 위한 여러 가지 포토다이오드를 사용하여 송수신 소자사이의 거리가 약 2.5m이고, 전체 시스템 속도가 115.2kbps의 전송속도를 가지는 가시광 시스템을 설계하여 구현 한다. 구현된 시스템의 성능분석을 위해 LED 와 포토다이오드 종류, LED 배열 수, 전송속도 따른 최대 송수신 거리를 구하고 여러 가지 구현시스템의 성능을 실험을 통해 분석한다. In this paper, as a study of the simple visible light communication(VLC) with LED light, the visible light communication system that are made up with the <TEX>$3{\times}3$</TEX> white LED array for visible light transmission, various photodiodes for visible light reception, and a non-carrier NRZ-OOK modulation scheme is designed and implemented to have a 115.2 kbps data speed at 2.5 m distance between transmitter and receiver. For the performance analysis of the developed VLC system, the maximum distance between VLC transmitter and receiver on the conditions of various transmission speeds, the number of LED array, or the various kind of LED and photodiode is obtained, and various performances are analyzed by experiments.

The growing preponderance of light emitting diodes (LEDs) for lighting has motivated research into their dual use for visible light communication (VLC) and navigation. VLC extracts a bit sequence from a series of photodetector scans. Among this data is an LED ID that ensures the reliable data association in navigation and data communication. Recovering the LED data and ID requires the accurate prediction of each LED’s projected position on the photodetector array to extract efficiently and reliably the LED ON–OFF status in each photodetector scan. Estimating the LED projected position is challenging because: 1) clutter and noise corrupt the measurements; 2) the LED status will be OFF in some scans; and 3) the predicted projection location sequence depends on the estimated rover state trajectory, which is uncertain and time varying. This paper presents a method to determine the $q$ -most probable data and the LED position sequences simultaneously for a time window of data, using Bayesian multiple hypothesis tracking techniques by maximizing the posterior probabilities. This paper focuses on the VLC data and the LED position sequence extraction, which includes rover state estimation. Implementation of the multiple hypothesis tracking algorithm is illustrated by postprocessed experimental results.

Li-Fi stands for Light-Fidelity. This technology is very new and was proposed by the German physicist Harald Haas in 2011. Light based communication system is the backbone of the future of the communication system. Li-Fi is a wireless technology that uses light emitting diodes (LEDs) for transmission of data. The development of the wireless communication leads to advance research in LiFi technology. The term Li-Fi states to visible light communication (VLC) technology that uses as medium to deliver high-speed communication in a fashion similar to Wi-Fi. Li-Fi comprises a wide range of frequencies and wavelengths, from the Infrared through visible and down to the Ultraviolet spectrum. The immense use of Li-Fi may solve some bottleneck of data transmission in Wi-Fi technology. With the innovation in technology and the number of users, the existing radio-wave spectrum fails to accommodate this need. To resolve the issues of scalability, availability and security, we have come up with the concept of transmitting data wirelessly through light using visible light communication (VLC) technology. This paper objective is to study and describe the LiFi technology. The improvement of the wireless communication leads to advance research in LiFi technology through Visible Light Communications (VLC) Technology.

As an application of visible light communication (VLC), visible light positioning (VLP) technology has great potential for vehicle positioning due to its characteristics of no electromagnetic interference, low cost, and high positioning accuracy. In addition, the light emitting diode (LED) in street lights, traffic lights and vehicle lighting systems makes this positioning solution attractive for vehicular applications. However, the modulated LED signal will bring blooming effects on the images captured by a complementary metal oxide semiconductor (CMOS) camera. And it will decrease the positioning performance. Meanwhile, positioning errors will happen when the CMOS camera is tilted. In the paper, a vehicle positioning scheme based on VLC is proposed and experimentally demonstrated. It uses LED street light as a transmitter and the CMOS camera as a receiver. To mitigate the blooming effect in the CMOS camera based VLC, a bit length estimation (BLE) based sampling scheme is proposed to obtain the reference location information from the captured images. In addition, a novel angle compensation scheme combined with a particle filter is proposed to improve the accuracy of vehicle positioning when the CMOS camera is tilted. The experiments are performed under moving speeds of 40 to 80 cm/s and the measured distances of 80 to 115 cm. Assuming the performance of the proposed demonstrator is not modified when upscaling its size to a real scenario (such as speeds of 4 to 8 m/s and distances between the LED and camera of several meters), it can be concluded that as the speed of the moving vehicle is 8 m/s, the proposed vehicle positioning scheme based on VLC can achieve positioning accuracy of 0.128 m and 0.13 m for the tilt angles of 9° and 15.5°, respectively.

The radio frequency spectrum has become very congested and scarce. A response to this dilemma is the implementation of visible light communications (VLC) technology, which is enabled by the dramatic development of light emitting diodes (LEDs) and laser diodes (LDs). VLC has become the most popular emerging telecommunication technology. This is due to the interesting advantages that it provides, which include an unlicensed and large bandwidth, a high throughput capability and a low implementation cost. VLC needs a pivot network in medium and long distance transmissions. The amplify‐and‐forward scenario between the backbone network and VLC is cost‐effective owing to its simplicity when compared to the decode‐and‐forward scenario. MPSK‐CSK is a typical example of cascaded systems in AF scenario with VLC where the backbone channel utilises PSK to convey the message. In this paper, we investigate a forward error correction scheme for cascaded MPSK‐CSK systems. A convolutional encoder is added to the MPSK‐CSK scheme to construct the hybrid trellis coded modulation scheme. Selected 8HTCM systems using set partitioning are investigated and results for a Gaussian channel are presented. Numerical results reveal that 8HTCM achieves up to 2.129 dB of asymptotic coding gain when compared to the corresponding un‐coded MPSK‐CSK system.

To transfer audio data using Visible Light Communication (VLC), Light Fidelity (Li-Fi) technology has been designed. This project aims to develop a system for faster and more secure transmission of data. At present, Bluetooth and Wi-Fi are two major short-range wireless technologies used for different wireless application. There are different disadvantages of these current technologies, such as costlier, higher power consumption, and data insecurity. There is a great demand, therefore, for a technology which can resolve all the disadvantages of current technology. VLC is an efficient alternate emerging. As a mode of transmission, this upcoming technology uses light. The visible light spectrum is operated by Li-Fi that is ten thousand times as many as the spectrum of radio wave. It uses visible light, rather than traditional radio waves, as a mode of transmission. Thus, it can be used in places where it is prohibited to use radio waves. Given its very high speed (3 to 108 meter/second), light is a source for high-speed communication needs. Light is always in straight line, but the atmospheric change bringing off the light rays deflection. The data rates in Multiple-Gigabit-per-second over a short distance could be provided with bandwidth of 300 THz available for VLC. Here, a VLC prototype is being developed with a significant increase in distance of transmission and an enhancement in channel capacity. An overview of audio transmission in VLC is provided by this prototype. Real-time audio broadcast prototype utilizing commercial Light Emitting Diode (LED) lamps is proposed in this paper. Experimental findings show that it is possible to provide realtime audio with a maximum distance of 2ft accomplished by proper layout of LED sources and concentration improvement effects. The lighting model is built and simulated within the room setting, which it shows a close relationship between light source layout and distribution of illuminance.