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The role of inter-satellite communication (ISC) is of great significance in the contemporary era of satellite technology. In this context, visible light communication (VLC) has emerged as a highly promising alternative to conventional radio frequency (RF) communication. This is especially true for small satellites like CubeSats, where constraints related to size, weight, and power (SWaP) are of utmost importance. However, VLC systems’ limited bandwidth makes it challenging to achieve large data rates and capacity. This can be evaded with the utilization of non-orthogonal multiple access (NOMA) as a fundamental technology to augment ISC based on VLC. Such schemes have already been evaluated and published in the public domain literature. There is, nevertheless, lack of information on the efficacy of utilizing cooperative NOMA (Co-NOMA) scheme in conjunction with VLC for a constellation of satellites, with limited power resources. This research study investigates the utilization of NOMA as the access technique for inter-satellite connections when communication is done through VLC under power restrictions, with a particular emphasis on reducing the bit error rate (BER) while enhancing the average sum rate (ASR) for distant satellites through Co-NOMA. The efficacy of the proposed methodology is verified through simulation results.

Assessing the motion of moving objects from video footage captured using multiple recording devices requires precise timing and location data, which remains equally important in mobile recording systems. Although capturing high-precision clocks and analyzing these images are effective methods for obtaining accurate time information, a definitive method for precisely determining the capture time from images of rapidly time-varying clocks at various exposure durations is currently lacking. This paper introduces a design method for a dynamic optical marker called the Optical Clock Beacon (OCB), which indicates the current time by integrating multiple point light sources. Our goal is to enable accurate determination of the capture time from images. We present a method for estimating this time using image analysis and validate its accuracy. The simplest OCB configuration translates the binary representation of the current time into a Gray code, with each bit’s state indicated by light sources of positive and negative logic. This approach allows the determination of an image capture time with precision matching of the exposure duration. Furthermore, we outline a design strategy that improves the time accuracy by making the light source configuration of each digit redundant, thus providing substantial design flexibility for the OCB. We also detail the prototype hardware and the image analysis system of the developed OCB, demonstrating through evaluation experiments that the anticipated time accuracy is achievable.

The delay jitter in the visible light communication (VLC) network is analyzed in this work. First, the delay jitter under single-user and multi-user scenarios is investigated and a closed-form expression is obtained, whose accuracy is verified by simulation. Second, through analyzing the delay jitter under two typical indoor light emitting diode (LED) layouts, we find that the mean user delay jitter under cellular layout is a little lower than that of square layout. Then, we study the delay jitter for mobile users, and the relationship among user movement speed, arrival rate and delay jitter in different scenarios. The delay jitter performance is evaluated assuming perfect coordinated multiple points (CoMP) transmission strategy in VLC network. Simulation results show that in the context of VLC, static users can experience an average delay jitter of up to $10^{-6}$ s, while mobile users can experience an average delay jitter of up to $10^{-5}$ s. Therefore, VLC network can provide users with good delay jitter performance and customized services to meet the higher service quality requirements of future users.

The low-pass characteristics of front-end elements including light-emitting diodes (LEDs) and photodiodes (PDs) limit the transmission data rate of visible light communication (VLC) and Light Fidelity (LiFi) systems. Using multiplexing transmission techniques, such as spatial multiplexing (SMX) and wavelength division multiplexing (WDM), is a solution to overcome bandwidth limitation. However, spatial correlation in optical wireless channels and optical filter bandpass shifts typically limit the achievable multiplexing gain in SMX and WDM systems, respectively. In this paper, we consider a multiple-input multiple output (MIMO) joint multiplexing VLC system that exploits available degrees-of-freedom (DoFs) across space, wavelength and frequency dimensions simultaneously. Instead of providing a new precoder/post-detector design, we investigate the considered joint multiplexing system from a system configuration perspective by tuning system parameters in both spatial and wavelength domains, such as LED positions and optical filter passband. We propose a novel spatial clustering with wavelength division (SCWD) strategy which enhances the MIMO channel condition. We propose to use a state-of-the-art black-box optimization tool: Bayesian adaptive direct search (BADS) to determine the desired system parameters, which can significantly improve the achievable rate. The extensive numerical results demonstrate the superiority of the proposed method over conventional SMX and WDM VLC systems.

The application of liquid crystal (LC)-based reconfigurable intelligent surface (RIS)-assisted transmitters in visible light communication (VLC) systems can guide and amplify the light emitted by light emitting diodes (LEDs). In this paper, we investigate the VLC system employing the RIS-assisted transmitter, where user fairness is maximized by optimizing the refractive index of the RIS module. To address the non-convex problem, we adopt the particle swarm optimization (PSO) algorithm. Simulation results illustrate that equipping the RIS-assisted transmitter in the system and using the proposed algorithm can significantly improve user fairness.

This research delves into the application of Digital Twins (DTs) in the realm of smart agriculture, with a particular focus on greenhouse and underground environments. By integrating computer simulations with empirical testing, we validate our hypotheses. A novel approach has been introduced that uses Visible Light Communication (VLC) for data exchange within greenhouses, along with a distinct system tailored for subterranean applications. This investigation explores how various factors influence communication effectiveness. Comprehensive testing of these systems has been conducted to evaluate their performance under a range of conditions and with varying orientations of light sources. Specifically, for our greenhouse configuration, we discovered that adjusting the system in a specific manner can substantially enhance signal quality, by nearly 10 dB at a distance of four meters, in underground scenarios. Furthermore, we have conducted evaluations using the most current WiFi and mobile networks, as well as Free Space Optics (FSO) networks, to ensure that our digital twin model is robust and capable of accurately transmitting data to a control room.

Due to its ability to reconfigure the optical channel, intelligent reflecting surface (IRS) has revealed its great potential for enhancing the performance of visible light communication (VLC) systems. In this paper, we apply a mirror array-based IRS in typical multiple-input multiple-output based VLC (MIMO-VLC) systems and optimize the IRS configuration to minimize the system bit error rate (BER). By utilizing the tight analytical BER upper bound, a BER minimization problem is formulated subject to the IRS configuration constraints. To solve this problem, an optimization algorithm is proposed which decomposes the original problem into three sub-problems, and the complexity of the algorithm is analyzed. The superiority of the obtained optimal IRS configuration scheme over the baseline scheme in terms of BER performance has been successfully verified through simulations in an indoor IRS-aided $4\times 4$ MIMO-VLC system applying different MIMO techniques.

The use of visible light communication (VLC) to support wireless coverage has been receiving increasing interest, due to factors that include its operation in a large unregulated spectrum and immunity against electromagnetic interference. On the other hand, the sensitivity of VLC network performance to the line-of-sight (LOS) link quality affects the system reliability. The emergence of reconfigurable intelligent surfaces (RISs) in optical domain opens the door for minimizing the impacts of the LOS link degradation on VLC networks, given the possibilities they provide for enhancing the non-LOS channel gain. In this paper, we propose optimizing the RIS-assisted VLC systems by controlling the RIS elements to maximize the network sum-rate while maintaining fairness in the user achievable throughput. Two types of RIS elements are considered, where the addressed non-convex optimization problems are handled using the genetic algorithm and the particle swarm optimization techniques, presenting improvement in network performance in terms of sum rate, fairness, and link outage ratio. In addition, we investigate the RIS-assisted VLC system performance in cases of handling mobile users, highlighting the trade-off between the variation in the optimization rate and the network performance.

Recently, visible light communications (VLCs) have attracted attention as a complement to wireless communications by radio frequency. In addition, the demand for Internet of Things (IoT) communications has increased in the last decade, and VLC-based IoT systems are being considered. Because IoT devices operate at various data rates, multirate transmission is required. Herein, we propose a scheme that supports multirate data transmission for synchronous optical code division multiple access systems. This scheme employs a generalized modified prime sequence code and multiple extended bi-orthogonal codes. The proposed scheme realizes multirate transmission with an arbitrary number of data rate levels by superimposing spreading codes of different codelengths. In addition, the proposed scheme eliminates not only interference between users with the same data rate, but also interference between users with different data rates. Furthermore, we investigated the bit error rate performance and energy efficiency of the proposed scheme, considering the effects of background light, dark current, and PIN photodiode noise including shot noise, and thermal noise.

The massive deployment of IoT connected devices brings up different modern problems, such as radiofrequency spectrum saturation and energetic requirements. Organic photovoltaics are good candidates for indoor energy harvesting and data reception in a simultaneous lightwave information and power transfer scenario applied for IoT, at which the non-directive channel significantly contributes to the optical system performance. However, achieving the channel impulse response of diffuse links requires complex numerical approaches. This article presents the first ever OPV model used in a Monte-Carlo ray-tracing simulation, associated to theoretical and experimental validation. Finally, for the first time, an optical simulation with an OPV receiver is realized in a cubic environment, from which the received optical power and generated current distributions were obtained. Results show that the employed OPV is suited for indoor energy harvesting to supply low power IoT nodes, and with proper dedicated front-end, could manage to receive optical data in a SLIPT scenario.

This paper presents a communications framework to overcome the connectivity constraints due to the nonavailability of the line-of-sight transmissions in indoor optical communication systems. This nonavailability can arise for various reasons, such as blockages due to physical objects, unfavorable device orientations or large distances between the transmitter and the receiving devices. The proposed system utilizes multiple intelligent reflecting surface (IRS) arrays and device-to-device (D2D) communications. The D2D communication is realized using infrared (IR) light-emitting diodes (LEDs) with limited output power for eye safety. The performance of this system depends significantly on the assignment of the mirrors in the IRS arrays to the appropriate user links and a direct combinatorial assignment search is too complex to implement. The proposed approach identifies the assignment of each mirror in the IRS arrays as a multi-armed bandit (MAB) problem, and the assignment of all the mirrors together as a combinatorial MAB (CMAB) problem. Since a simultaneous movement of all the IRS mirrors during the implementation of the CMAB algorithm could cause frequent link disruptions, a CMAB algorithm with low disruptions (CMAB-LD) is proposed to obtain the best mirror assignment with low link disruptions. Simulation results demonstrate that the proposed algorithm can provide significant improvement in reward performance and the total reward increases by more than 100% over random mirror assignments when the channels are blocked with high probabilities. In small size problems, the proposed CMAB-LD is found to achieve the global optimal solution in just a few rounds of full arm explore operations.

The fifth-generation (5G) wireless communications have been deployed in many countries with the following features: wireless networks at 20 Gbps as peak data rate, a latency of 1-ms, reliability of 99.999%, maximum mobility of 500 km/h, a bandwidth of 1-GHz, and a capacity of 106 up to Mbps/m2. Nonetheless, the rapid growth of applications, such as extended/virtual reality (XR/VR), online gaming, telemedicine, cloud computing, smart cities, the Internet of Everything (IoE), and others, demand lower latency, higher data rates, ubiquitous coverage, and better reliability. These higher requirements are the main problems that have challenged 5G while concurrently encouraging researchers and practitioners to introduce viable solutions. In this review paper, the sixth-generation (6G) technology could solve the 5G limitations, achieve higher requirements, and support future applications. The integration of multiple access techniques, terahertz (THz), visible light communications (VLC), ultra-massive multiple-input multiple-output ( $\mu {\mathrm{ m}}$ -MIMO), hybrid networks, cell-free massive MIMO, and artificial intelligence (AI)/machine learning (ML) have been proposed for 6G. The main contributions of this paper are a comprehensive review of the 6G vision, KPIs (key performance indicators), and advanced potential technologies proposed with operation principles. Besides, this paper reviewed multiple access and modulation techniques, concentrating on Filter-Bank Multicarrier (FBMC) as a potential technology for 6G. This paper ends by discussing potential applications with challenges and lessons identified from prior studies to pave the path for future research.

In this article, the estimation of random channel gain is studied for a single-input single-output (SISO) visible light communication (VLC) system. Five different estimators, namely maximum likelihood (ML), least square (LS), maximum posteriori probability (MAP), linear minimum mean square error (LMMSE), and minimum mean square error (MMSE), are proposed. The performances of these estimators are compared with the derived Bayesian Cramér–Rao lower bound (BCRLB), which can be used as a benchmark to evaluate the efficiency of the unbiased estimators. The presented analytical results, corroborated with Monte Carlo simulations, indicate that the MMSE estimator provides the best results. Additionally, the increasing number of pilot symbols as well as the ascending transmitted power improve the system performance. On the other hand, the noise variance has a negative effect on the channel estimation in terms of mean square error (MSE), and thus, it can dramatically reduce the performance of the estimators. [ABSTRACT FROM AUTHOR]

This work proposes a new paradigm for contactless vital sign sensing that adopts an integrated ultrawideband (UWB) radar and hybrid optical wireless communication (OWC) technologies. The proposed system is composed of a sensor node and a receiver node. The sensor node is responsible for detecting continuous vital sign signals and then transmitting these signals via the hybrid OWC transmitters, which are composed of a visible light communication transmitter and an infrared transmitter. The contactless UWB radar adopts low intermedium frequency demodulation rather than the conventional direct down conversion topology to avoid severe direct current (DC) offset issue. The advantages of this merged configuration do not only help reduce radar complexity but also provide the required modulated signal with vital signs for the subsequent OWC system. Moreover, the receiver node has an OWC receiver module for receiving vital signs that utilizes a photodiode-based receiver with an analog filter and digital signal processing mechanisms. The proposed architecture exhibits the potential to reduce radar complexity and provide new solutions to replace the conventional contact sensing system used in hospitals or nursing homes. [ABSTRACT FROM AUTHOR]

Indoor communication and positioning are significant fields of applications for indoor Internet of Things (IoT) given the rapid growth of IoT in smart cities, smart grids, and smart industries. Visible light positioning (VLP) has become more and more attractive for researchers to provide indoor location-aware IoT services. Additionally, artificial intelligence (AI) has attracted considerable research effort to address the challenges in visible-light communication (VLC) systems. This is an emerging technology in next-generation wireless networks. However, despite the rapid progress, the use of AI in localization, navigation, and position estimation is still underexplored in VLC systems, and various research challenges are still open. This methodological review summarizes the research efforts regarding the use of AI in the field of VLP, to improve the position estimation accuracy in both two-dimensional (2D) and three-dimensional (3D) indoor IoT applications. This treatise also presents open issues and potential future directions for motivating further research in the field. Various databases were utilized in this paper: Scopus, Google Scholar, and IEEE Xplore; obtained 88 papers from 2017 to early 2023. Most (68%) of the AI articles in VLP systems are machine learning (ML) methods applied for localization and position estimation in VLC systems, while the other 32% of the research articles focussed on evolutionary algorithms. ML and evolutionary models may present limitations in terms of complexity and time-consuming nature but offer highly accurate, robust, reliable, and cost-effective results in terms of position estimation over conventional approaches.

This article investigates the characteristics of the signal-dependent noise (SDN) and corresponding modulation design in nonlinear visible light communication (VLC) systems. We first provide the noise model including SDN and signal-independent noise (SIDN) components. Then, we conduct three groups of comparative experiments to explore the noise characteristics in real VLC systems. Experimental results show that the dominance of SDN or SIDN is related to the linearity of VLC system. In a highly linear VLC system, the noise significantly increases with the signal strength. While in a VLC system with nonlinear devices, large nonlinear noise may make SDN less obvious. Based on the experimental results, a modulation optimization method is proposed for the VLC system with SDN. The symbol error rate (SER) of the optimized modulation is much lower than that of the uniform modulation in flat channel. Furthermore, we explore the effect of SDN on linear minimum mean square error (LMMSE) equalization. Simulation results show that the root mean square error of symbol estimation adopting LMMSE equalization is positively correlated with the modulation level. Moreover, the optimized modulation also outperforms the uniform modulation in the inter-symbol interference channel.

This article proposes an image sensor communication (ISC) system based on light trails using rotary LEDs. The light trail refers to an optical phenomenon where light appears elongated and forms a trajectory due to the movement of luminous objects. In this study, we developed a propeller LED transmitter (P-Tx) that rotates LEDs with a propeller to generate and transmit light trail signals. According to the LED's rotation radius, the proposed system segments light trails to achieve high-capacity data transmission at short distances and high-trust transmission at long distances. In addition, we perform the rotation coordinates system conversion for the captured light trails to accurately and simply detect the signal LEDs' coordinates. We experimentally evaluate the proposed system's communication performance and data rate. The experimental results demonstrate that our system is capable of meeting communication requirements at various distances and exhibits significant potential in enhancing the data transmission rate of ISC.

Sparse multipath channel impulse response (CIR) estimation schemes are conceived for optical orthogonal frequency division multiplexing (O-OFDM) visible light communication (VLC) systems. We commence by deriving the input-output models for both asymmetrically clipped optical OFDM (ACO-OFDM) and direct current-biased optical OFDM (DCO-OFDM) systems. A multipath CIR model is derived that captures both the diffusive as well as specular reflections of the VLC channel. Next, we introduce both the sparsity-agnostic conventional least square (LS) and the linear minimum mean square error (LMMSE) channel estimation (CE) techniques. This is followed by the orthogonal matching pursuit (OMP)-based sparse recovery technique, which exploits the delay-domain sparsity of the CIR. Furthermore, a novel sparse multipath CIR estimation scheme is proposed using the Bayesian learning (BL) framework, which requires only a limited number of pilot subcarriers, hence resulting in a reduced pilot overhead as compared to other state-of-the-art (SoA) CE techniques. The Bayesian Cramer Rao lower bound (BCRLB) as well as the Oracle-minimum mean squared error (O-MMSE) estimator are also derived for benchmarking the estimation performance of the proposed BL-based framework. Our simulation results demonstrate that the proposed BL method outperforms other existing sparse and conventional CE methods in terms of various metrics, such as the normalized mean-square-error (NMSE), the outage probability (OP), and the bit error-rate (BER) despite its reduced pilot overhead.

This paper presents the successful reception of visible light communication (VLC) signals, transmitted from an LED array, by an image sensor that utilizes a rolling shutter while driving at 40 km/h. The rolling shutter image sensors used in commercial cameras, such as those found in smartphones and dashcams, capture images line by line at a fast rate, allowing for VLC signal reception in vehicular environments. By analyzing the relationship between the signal reception rate for each line and the frame rate, we demonstrate that parallel VLC signals transmitted from the LED array can be received even while in motion. Notably, to our knowledge, this is the first time that an automobile moving at 40 km/h has successfully received a VLC signal.

Blanking non-linearity is broadly used in impulsive noise communication environments due to its efficiency and ease of deployment to mitigate such noise. During the blanking procedure, data samples with impulsive noise are identified and clipped to zero, which removes impulsive noise from the system thereby, improving the system performance. In this regard, this paper investigates the performance of hybrid power line communication-visible light communication (PLC-VLC) systems with blanking nonlinearity. The signal-to-noise (SNR) ratio at the output of the blanking device is deduced using a closed-form analytical expression. The results show that there is good agreement between simulation results and theory if there is a sufficiently large number of orthogonal frequency division multiplexing (OFDM) sub-carriers. In addition, the study also indicates that the blanking method is more effective in curbing impulsive noise in comparison to the clipping technique. According to the threshold optimisation investigations, there exists a worst-case SINR value that minimizes the output SNR at the OFDM receiver after blanking. Furthermore, the findings also revealed that proper blanking threshold selection is essential for obtaining the best performance.

The risk of information leakage increases when the relay technology is introduced to extend the communication range and improve the quality of communication services of cell-edge users in visible light communication (VLC) systems. To evaluate these security risks, physical layer security (PLS) performance for decode-and-forward (DF) relay-aided VLC system is investigated in this paper. Specifically, the theoretical expressions of the upper and lower bounds of the security outage probability (SOP) for the DF relay-aided VLC system under the amplitude constraint are obtained based on a stochastic geometry analysis method. Monte Carlo simulation validates the correctness of the derived theoretical expressions of the upper and lower bounds of the SOP. Moreover, simulation results show that the security outage performance of the DF relay-aided VLC system is deteriorated compared with the non-relay VLC system. Furthermore, the influences of the eavesdroppers' distribution density, the radiation radius of LED source, the radiation radius and deployment height of the relay on the SOP have been investigated. Last but not least, the optimal deployment height of the relay can be determined for achieving the optimum security outage performance. These parameters can effectively guide the design of the secure relay-aided VLC system.

Vehicular Visible light communication (VLC) technology has recently attracted much interest from researchers and scientists. This technology enables connectivity between vehicles and infrastructures along the road by using vehicles’ headlights and taillights as wireless transmitters. The reliability of vehicle-to-vehicle (V2V) VLC systems is affected by several factors, such as car mobility, optics system design, and visibility conditions, where the first two have the most impact on the VLC system performance. This paper, therefore, focuses on the relative positions of the cars and the design of the optics, especially on the receiving end, which has been proposed with the use of a polar detector instead of the rectangular detectors commonly used in the literature. We investigate the achievable gain compared to the conventional detector for different vehicle locations, utilizing a professional optical system design and ray tracing approach. Then, to improve the performance, we introduce the utilization of an imaging receiver by integrating the polar detector with different optical commercial lens combinations, such as Fresnel and Aspherical lenses. To further improve the V2V system performance, we propose a novel optical lens combination design by integrating double-convex lens with half-Plano-concave lens, which allows the correction of more optical aberrations, such as chromatic and spherical aberration. Utilizing the non-sequential ray tracing tools, we designed these VLC systems and perform a realistic channel modeling study considering the typical 3D CAD models of vehicles and roads as well as the possibility of horizontal and vertical movement between the vehicles. Based on the channel impulse responses (CIRs) obtained from the ray tracing simulations, we analyzed the performance of V2V VLC systems with all lens combinations at different vehicle positions on the road. We further investigated the impact of different system parameters on the overall V2V system performance, such as receiver diameter and bandwidth. The obtained results demonstrated that with a carefully chosen system and lens parameters, the proposed system design of lens combination provides an enhancement of up to 7 dB in total received power compared to the case without a lens. Our results also revealed that the proposed system design outperforms the benchmark ones for all lateral displacements and longitudinal distances.

In many optical wireless communications systems, power efficiency is paramount. In others, flexibility is important. To achieve these goals, this paper presents a novel transmission scheme dubbed asymmetrically clipped optical Hadamard coded modulation (ACO-HCM). ACO-HCM combines the characteristics of real-valued non-negative orthogonal frequency-division multiplexing (OFDM) and Hadamard coded modulation (HCM). Unlike OFDM, which is based on the Fourier transform and therefore delivers a continuous waveform, ACO-HCM provides a discrete set of amplitudes. This feature is desirable for nonlinear channels. Error probabilities are analytically calculated for a linear receiver similar to the decorrelation receiver in direct-sequence code-division multiple access (DS-CDMA). Maximum-likelihood sequence estimation is also investigated and shown to outperform the linear receiver, particularly in the presence of a time-dispersive channel. The peak-to-average power ratio of ACO-HCM is derived for the electrical as well as the optical domain in closed form.

We propose a two-level dimmer based on binary distribution matching where a low-rate signal controls the output probability distribution of a high-rate bit sequence, which can be used in region-of-interest (RoI) signaling applications. To reduce the rate loss of the dimmer, we propose the extended multiset-partition distribution matching (EMPDM) algorithm with a novel binary-tree-structure implementation. In addition, we introduce 4p-EMPDM, a compact version of EMPDM, which has a typical composition (TC) and four leading composition pairs (CPs). The codebook of 4p-EMPDM includes only run-length-aware codewords, which reduces the maximum run-length of the transmitted bit sequence by 4.27 times. Hence, it guarantees flicker mitigation for visible-light RoI signaling systems at 6 kHz without using any run-length limited code (non-RLL). Using experimental data collected from the low-rate RoI signaling prototype, we introduced a threshold range where both intensity and area information of the received training symbols can be exploited to optimize the shaping ratios of the 4p-EMPDM dimmer. Because of the non-RLL feature, the proposed system can support soft-decision forward-error-correction (FEC) decoding to improve reliability. Our system outperforms related systems based on hybrid modulation schemes in terms of spectral efficiency, bit rate, and minimum required optical clock rate.

As the demand for wireless capacity continues to grow, highly directional wireless communication technologies have the potential to provide massive gains in area spectral efficiency. However, novel challenges arise when considering bidirectional connectivity and multi-cell/multi-user systems with highly directional links. Some of these challenges can be alleviated with the introduction of asymmetric connectivity where the highly directional links are used solely for downlink transmission. As an example, we consider asymmetric links with an optical wireless communication (OWC) downlink and sub-6 GHz RF uplink. More specifically, we consider visible light communication as an instance of OWC, although the presented analysis and validation are applicable to alternative OWC technologies and other simplex downlink transmission technologies. While asymmetric connectivity has been previously demonstrated in scenarios like this, the impact of control-plane asymmetry has not been explored, to our knowledge. In this paper, we first introduce the novel challenges related to local handshaking in wireless networks with control-plane asymmetry. We then develop a theoretical framework for throughput analysis in a network where the sub-6 GHz RF channel is shared between a conventional RF link and an asymmetric RF/OWC link. This analysis is validated via simulation and verified in a testbed system using Mango WARP3 software defined radios and a commercially available RF access point. Finally, we use the derived throughput equations to analyze the impact of various protocol parameters and demonstrate one potential use of the derived equations to evaluate sum throughput in the presence of an unreliable OWC link. [ABSTRACT FROM AUTHOR]

The availability of LED-based headlights and taillights makes possible the use of visible light communication (VLC) as a wireless access technology for vehicle-to-vehicle (V2V) communications. A critical concern to establish a reliable VLC link between two moving vehicles is the number of photodetectors and their locations on the destination vehicle. In this paper, we experimentally investigate the usage of dual photodetectors for a vehicular VLC system with selection combining to enhance signal reception in mobile conditions. We measure the electrical receive signal-to-noise ratio (SNR) for each individual photodetector as well as at the output of selection combiner in two different tracks involving straight and curved roads. Through data fitting to experimental data, we obtain a probability density function (PDF) to describe the instantaneous SNR. Based on the PDF, we derive a closed-form expression for the average bit error rate (BER) in the form of a finite summation and compare it with the measurements. [ABSTRACT FROM AUTHOR]

In this paper, we consider unmanned aerial vehicles (UAVs) equipped with a visible light communication (VLC) access point and coordinated multipoint (CoMP) capability that allows users to connect to more than one UAV. UAVs can move in 3-dimensional (3D) at a constant acceleration, where a central server is responsible for synchronization and cooperation among UAVs. The effect of accelerated movement in UAV is necessary to be considered. Unlike most existing works, we examine the effects of variable speed on kinetics and radio resource allocations. For the proposed system model, we define two different time scales. In the frame, the acceleration of each UAV is specified, and in each slot, radio resources are allocated. Our goal is to formulate a multi-objective optimization problem where the total data rate is maximized, and the total communication power consumption is minimized simultaneously. To handle this multi-objective optimization, we first apply the scalarization method and then apply multi-agent deep deterministic policy gradient (MADDPG). We improve this solution method by adding two critic networks together with two-stage resource allocation. [ABSTRACT FROM AUTHOR]

The 3D time-of-flight (ToF) cameras have recently received a lot of attention due to their wide range of applications. Despite remarkable advancements in ToF imaging, state-of-the-art ToF cameras are still afflicted by the power hungriness of their illumination sources. To tackle this problem, we exploited existing lighting infrastructure, which ensures the ubiquitous presence of modulated light sources in indoor spaces that serve as opportunity illuminators. We explored the bistatic geometry for passive imaging using the pulse-based ToF approach. Our work is inspired by the recently introduced visible light communication (VLC) or light-fidelity (Li-Fi) infrastructure. VLC allows the infrastructure to provide indoor simultaneous illumination, communication, and sensing (SICS). To this end, we designed a bistatic geometry for the purpose of attaining passive 3D imaging. Such capabilities are achieved by exploiting the pulse shape of the autocorrelation function of real optical signals generated by VLC/Li-Fi modules (e.g., OpenVLC and LiFiMAX). We demonstrated passive imaging by means of matched filtering. In this work, we also studied different sampling strategies in the time-shift domain, including uniform, random, and sparse rulers, which is another step forward toward preserving high depth accuracy with a minimal number of measurements. The proposed methodology achieved successful depth reconstruction with negligible root-mean-square error (RMSE) for the low signal-to-noise ratio (SNR) of the measurements. Parametric models, such as Gaussian and sum of sines, are used to characterize the cross correlation functions and allow for robust parametric depth retrieval from a few measurements. Moreover, we attained a 20-mm worst case error for a target at 25 cm. The experiment proved that the bistatic passive depth reconstruction is feasible. [ABSTRACT FROM AUTHOR]

Memory polynomial (MP) method has been widely applied to the linearization area in wireless communications, in order to depress the nonlinear and memorial effects caused by the power amplifier. In MP, least square algorithm is usually utilized to calculate the coefficients, which may encounter numerical inaccuracies in high dimensional MP matrix inverse computations when the nonlinear effects are intensified. Aiming at this problem, we propose a memory polynomial with memory elimination (MP-ME) scheme, which is intended to separate the suppression processes of memory and nonlinearity, thus improves the detection performance by reducing the dimension of conventional MP matrix. With the proposed ME structure, we extract the linear component in polynomial’s linearization output by reconstructing and eliminating the memory signal, so the matrix calculation with high dimension in MP is avoided. Computer simulations are carried out considering the nonlinear characteristics of the light emitting diodes in visible light communications, and the results show that MP-ME can improve the bit error rate performance of MP significantly. [ABSTRACT FROM AUTHOR]

Visible Light Communication (VLC) is a rapidly growing technology which can supplement the current radio-frequency (RF) based wireless communication systems. VLC can play a huge part in solving the ever-increasing problem of spectrum scarcity because of the growing availability of Light Emitting Diodes (LEDs). One of the biggest advantages of VLC over other communication systems is that it can provide illumination and data communication simultaneously without needing any extra deployment. Although it is essential to provide data rate at a blazing speed to all the users nowadays, maintaining a satisfactory level in the distribution of lighting is also important. In this paper, we present a novel approach of using mirrors to enhance the illumination uniformity and throughput of an indoor multi-element VLC system architecture. In this approach, we improve the Signal-to-Interference plus Noise Ratio (SINR) of the system and overall illumination uniformity of the room by redirecting the reflected LED beams on the walls to darker spots with the use of mirrors. We formulate a joint optimization problem focusing on maximization of the SINR while maintaining a reasonable illumination uniformity across the room. We propose a two-stage solution of the optimization problem: design solution and communication solution. In the design optimization, we formulate an equivalent binary linear optimization to achieve the best illumination quality by optimizing the mirror placements and the LEDs’ transmit powers. In the communication problem, however, we aim to improve the throughput of the system using a fair utility metric based on maximizing the minimum user’s data rate. Due to non-convexity of the communication problem, we propose three different heuristic solutions and analyze their performance. We also show that about threefold increase in average illumination and fourfold increase in average throughput can be achieved when the mirror placement is applied which is a significant performance improvement. [ABSTRACT FROM AUTHOR]

We consider error-rate prediction for dual-use lighting systems with visible light communication (VLC) functionality. Since light planning rather than communications engineering is usually the driving discipline for practical dual-use settings, we extract VLC channel parameters as a by-product from advanced 3-dimensional (3D) light-planning models. By this means, we attain realistic signal-to-noise ratios for exemplary positions of a VLC receiver, which allows us to predict corresponding end-to-end bit error rates (BERs). Specifically, our procedure accounts for important aspects of state-of-art lighting systems, such as realistic light distribution curves of employed luminaires, possible presence unmodulated light sources, and, particularly, adaptive dimming operations in response to prevalent sunlight. In this paper, we (i) devise a methodology for VLC systems with optical receive filtering to convert photometric quantities into radiometric quantities, (ii) present examples of BER predictions for selected modulation schemes within some basic office environments, and (iii) conduct an analysis of the resulting simulation accuracy for a particular 3D light-planning tool. Simulation results show that our approach is indeed suited to predict realistic end-to-end BERs for dual-use lighting/VLC systems. Moreover, our procedure is fairly general and may be tailored to specific practical office settings and particular light plans of interest.

This treatise presents a framework for the optimisation of a colour-based optical spatial modulation for visible light communication (VLC). The focus is particularly on the conflicting interests between illuminance and signal transmission. The system under consideration is configured with a non-line-of-sight (NLoS) model, based on the joint use of colour shift keying (CSK) and optical spatial modulation (OSM) with intensity modulation and direct detection (IM/DD). With the adaptation of the aforementioned optical techniques and convex optimisation, the design and development of a colour-based optical wireless system is carried out. Firstly, an optimisation problem with the intention of minimising the total luminous intensities of the light emitting diode (LED) arrays subject to the transmitting LED array’s optical power budget, minimum required illuminance level, LED-user channel conditions and latency intolerant users’ (LITUs) quality-of-service (QoS) target constraints is defined. Secondly, a coordinated algorithm for the selection of a transmitting LED array, maintenance of a particular illuminance and signal-to-interference-plus noise ratio (SINR) levels during symbol transmission is designed. Lastly, through computer simulations, a numerical analysis is carried out to demonstrate and evaluate the performance of the algorithm. During the transmission of all symbols, the proposed framework is capable of satisfying the SINR target for LITUs while reducing the optical power by approximately 20% to 25% and 20% to 75% for transmitting and non-transmitting LED arrays, respectively. Additionally, provided that the required illuminance level is specified within the standardised levels of 300 lux to 1500 lux, the proposed system can provide adequate illuminance as per the users’ requirement at all points where either a LITU or a latency tolerant user (LTU) is located at any given instance. However, fair SINR levels are not guaranteed at the points where the LTUs are positioned. On the other hand, the algorithm disposes low illuminance levels ranging from 100 lux to 250 lux at locations towards the room boundaries where there are no users. The proposed system is able to achieve data rates of 5 Mbps to 25 Mbps using commercially-off-the-shelf LEDs.

Visible light communication (VLC) based on image sensor (IS) as the receiver is one of the supplementary technologies of radio frequency communication. By combining with image processing technology, VLC has various applications in smart home, underwater communication and intelligent transportation system (ITS). In the paper, it focuses on the vehicle positioning service provided by VLC in ITS. For the weak image spatial separability caused by long-distance VLC transmission between the vehicle and the infrastructure, it will lead to serious deterioration in communication and positioning performance. Thus, a deep learning-assisted IS-based visible light positioning (VLP) scheme is proposed and experimentally demonstrated. At the transmitter, a novel coding method is proposed to support both short-distance and long-distance communication based on VLC in ITS. Meanwhile, it can meet the dimming requirements of LED road infrastructure. In addition, in the proposed VLP scheme, it uses an artificial neural network (ANN) to predict the location of the vehicle. It is demonstrated that long-distance communication, high-accuracy positioning, and LED dimming can be realized simultaneously. The results show that, by using the proposed scheme, as the transmission distance is 2 m, the bit error rate (BER) of system is 1.25 × 10−4. And the average positioning error is 19.8 mm at the maximum simulated distance of 30 m.

Visible light communication has attracted significant attention due to advantages such as high transmission speed, good security, high confidentiality, environmental protection, and lack of need for spectrum authorization. Herein, the problem of absorption of light in the visible band in thin silicon films is examined, and a dual composite nanostructure array based on nanoholes of two sizes is proposed to increase visible light absorption. Light absorptivity was determined to be greater than 80% at wavelengths between 400 and 678 nm. Moreover, using finite-difference time-domain numerical simulations, the distributions of the electric field at specific wavelengths were obtained, the propagation modes at these wavelengths were examined, and the effect of these modes was analyzed according to the electric field distributions. The proposed dual composite nanostructured silicon film can be used in photovoltaic devices to improve visible light absorption.

We propose to utilize a commercially available DIALux lighting design software for simulation and planning of machine learning (ML) based angle-of-arrival (AOA) visible light positioning (VLP) systems. Here, different ML models, for example, second order linear regression (LR), artificial neural-network (ANN), and convolutional neural-network (CNN) are employed. The proposed VLP simulator works well with different ML algorithms. The results show that the proposed scheme can acts as an effective indoor VLP planning and design tool. Besides, it may also alleviate the training data collection in ML based VLP systems.

Visible light communication (VLC) is considered a new technology for interconnecting devices in 5G and beyond. VLC can provide additional bandwidth for communicating devices which can help to reduce the radio frequency bandwidth congestion. In this work, we aim to maximize the bandwidth usages for VLC. The proposed modulation technique can impose more bits due to the combined utilization of both pulse height and width changes. Moreover, we subdivide the single bit duration to impose more bits for data transmission. The proposed modulation is capable of transmitting more bits by utilizing fewer optical pulses than other traditional modulation techniques such as multilevel modulation, on-off keying, pulse width modulation, pulse position modulation, pulse amplitude modulation, and multiple pulse position modulation. We have evaluated the theoretical bit error rate (BER) expression in terms of average signal to noise ratio and compared the experimental BER performance for the proposed system. The experimental results demonstrate that the proposed modulation technique can achieve a communication distance of 3 m in an indoor environment.

The nonlinearity induced by light-emitting diode (LED) affects the normal transmission and reception, which significantly limits the performance of visible light communication (VLC) system. To address the problem induced by the nonlinearity of LED, a post-distorter for orthogonal frequency division multiplexing (OFDM) based VLC is proposed in this paper. Radial basis function (RBF) interpolation, known as an excellent function approximation method, is investigated to implement the nonlinearity mitigations. To further remove the memory effect of LED, which could not be ignored, we propose to extend RBF to a high-dimensional interpolation so that it can eliminate both nonlinearity and memory effect simultaneously. The performance of the proposed RBF extension interpolation is verified by numerical simulations, and a better performance in suppressing nonlinearity is obtained in VLC-OFDM systems as compared with the frequency domain nonlinear compensation method. A signal-to-noise ratio gain of 2dB in terms of ${{{E}_b} \mathord{/ {\vphantom {{{E}_b} {{N}_0}}} } {{N}_0}}$ can be obtained when bit error rate is about 6*10−7 at 6dB power back-off (PBO), while 6dB gain can be achieved when BER is 2*10−4 at 4dB PBO.

Wireless intensity-modulated optical channels feature some very specific differences compared to wireless radio channels. These properties have a strong impact on the performance of digital modulation techniques. This paper discusses basics to consider when designing optical intensity modulation schemes. We introduce an error event probability expression for such modulation schemes that is generally applicable for all non-negative waveforms. We indicate the importance of amplitude fluctuations and the influence of pulse shaping on the power efficiency in the optical domain. In numerical examples, we apply the error event probability expression to modifications of orthogonal frequency-division multiplexing and to Hadamard coded modulation.

In the design of reconfigurable intelligent surfaces (RISs)-aided visible light communication (VLC) systems, most studies have focused on the deployment of mirror arrays and metasurfaces on walls to influence signal propagation and enhance communication performance. This paper provides a new research direction in the design and performance optimization of RIS-aided VLC systems whereby voltage-controlled tunable liquid crystals (LCs) are deployed as part of the VLC receiver. The purpose of the LC RIS is to provide incident light steering and intensity amplification in order to improve the received signal strength and the corresponding achievable data rate. More specifically, an LC RIS-based VLC receiver design is proposed and its operating principles and the channel model for a VLC system with such a receiver are provided. Since the refractive index of the LC RIS plays a critical role in the wave-guiding and light amplification capabilities of this novel receiver, a rate maximization problem is considered to achieve the optimal refractive index and the required voltage to obtain the best light amplification and data rate performances. This communication design problem is a non-convex optimization problem for which a metaheuristic approach is developed based on the sine-cosine algorithm. Simulation results are used to confirm the considerable data rate improvement by the proposed LC RIS-based VLC receiver and optimization algorithm when compared to a VLC receiver without the LC RIS and a baseline scheme, respectively.

Visible Light Communication (VLC) is a key technology for the sixth-generation (6G) wireless communication thanks to the possibility of using artificial environmental lights as a data transfer channel. Although VLC systems are more resistant against interference and less susceptible to security vulnerabilities like most wireless networks, VLC is even inherently susceptible to eavesdropping attacks. Moreover, since VLC is considered an enabling technology for 6G, specific mechanisms are needed to enforce data security. This paper considers improving the security of the next generation of wireless communications by using the Watermark Blind Physical Layer Security (WBPLSec) in VLCs. The main intuition is that RGB LEDs offer the possibility for Wavelength Division Multiplexing (WDM) as a useful support for the Spread-Spectrum (SS) watermarking. In this paper, we propose an approach that aims at obtaining VLC Physical Layer Security (PLS) by combining watermarking with an RGB LED jamming. We provide a performance analysis of the proposed security architecture based on the secrecy capacity in terms of its existence and outage probability. We prove that WBPLSec can be used to significantly improve confidentiality in the next generation of wireless communications. The results offer the possibility of creating a secure region around the legitimate receiver by leveraging the jamming optical power.

DC-biased optical orthogonal frequency division multiplexing (DCO-OFDM) has been proposed in visible light communication (VLC) to overcome the limited modulation bandwidth of light emitting diode (LED). Due to the implementation of the inverse fast Fourier transform at the DCO-OFDM transmitter, DCO-OFDM suffers from its high peak-to-average power ratio (PAPR), which restricts its use in some VLC applications, especially where the optical power efficiency is a crucial requirement. That is because the LEDs used in VLC systems have a limited optical power-current linear range. To this end, a novel discrete Fourier transform spread-optical pulse amplitude modulation (DFTS-OPAM) signal scheme based on the single carrier-interleaved frequency division multiple access (SC-IFDMA) signal is introduced in this paper to address the high PAPR issue of OFDM. DFTS-OPAM is achieved by considering a PAM as an SC-IFDMA data symbol and duplicate the output vector of the fast Fourier transform at the SC-IFDMA transmitter side. Simulation results show that the PAPR of the proposed scheme is 7 dB lower than that of DCO-OFDM. Furthermore, this significant PAPR improvement is experimentally investigated where the practical results show that the proposed scheme can provide more 2.5 dB reduction in the average transmitted power requirement compared to DCO-OFDM and can subsequently increase the maximum achieved distance between the transmitter and the receiver up to 44%.

Seamless light fidelity (LiFi) communications in a realistic indoor environment faces a number of important challenges including the loss of line-of-sight (LOS) link due to the random orientation of mobile devices or blockage by users or furniture in the room. These effects make the frequency response of the LiFi channel highly environment-dependent. The dynamic nature of the channel is not only dependent on the geometrical configuration of the room but also on the user behavior. In this paper, we investigate the hypothesis that, deep learning (DL) based LiFi communication techniques can effectively learn the distinct features of the indoor environment and user behavior to provide superior performance compared to conventional channel estimation techniques particularly when access to real-time channel state information (CSI) is restricted. In particular, we implement DL methods in two different problems, namely, signal detection and resource allocation for orthogonal frequency division multiplexing (OFDM) LiFi systems. To effectively test this hypothesis, a realistic LiFi channel impaired by random device orientation and blockage is simulated considering different geometrical configurations and user behavior in an indoor environment, e.g. presence or lack of furniture and varying user distribution defined by a conditional hotspot model. The simulation results confirm that DL-based LiFi systems with partial CSI are able to offer close performance to the optimal signal detection and resource allocation with perfect CSI. Moreover, the DL-based techniques demonstrate substantial gain against conventional benchmark schemes that employ channel estimation algorithms such as least squares (LS) or minimum mean square error (MMSE) and this gain increases in a more realistic or complex indoor environment, e.g. room with furniture or a hotspot scenario.

Color shift keying (CSK) communicates information by emitting light that hops instantaneously from one chromaticity to another. This rapid hopping is too fast to be noticeable by human vision, which senses only the time-averaged color, as the human vision’s critical fusion threshold and critical color fusion threshold both lie under 100 Hz. That is, color shift keying exploits the human vision’s temporal irresolution of instantaneous fluctuations across chromaticities. Left unexploited, up to now, is the intensity-fluctuation tolerance of the human vision, that humans do not perceive small intensity fluctuations of $\pm 4\%$. This newly proposed constellation-design scheme can raise by $49 \%$ the designed color-shift-keying constellation’s $d_{\min }^\circ$ (i.e. the maximally achievable “minimum distance” $d_{\min }$). Moreover, this enhanced $d_{\min }^\circ$ can be approximated as a simple mathematical expression in terms of the design parameters to serve as a rule-of-thumb to enhance color-shift-keying systems.

This paper focuses on the combined technique of device-to-device (D2D) and coordinated multipoint joint transmission (CoMP-JT) to bridge the indoor industrial wireless gap with LiFi-based networks. It also considers the mobility challange of industrial Internet-of-Things (IIoT) within a realistic scenario. Using the semiangle at half illuminance of the LiFi access point and D2D transmitting IIoT, we derive a coverage model for the communication range. Using stochastic geometry, the analytical expressions for CoMP-JT probability and coverage performance are derived in terms of different parameters, such as transmitter densities and bias factor. The analytical approximations match quite well with the Monte Carlo method-based simulation results.

A camera with an image sensor is an important alternative device to a photodiode-based receiver of visible-light communication in outdoor scenarios. The intrinsic color separation capability of a camera qualifies color shift keying (CSK) modulation as an intuitive solution to enhance the achievable data rate. The symbol error rate (SER) of CSK modulation is considerably important to system design and performance evaluation, and has not been extensively investigated for outdoor optical camera communication systems from the viewpoint of camera-based channel and image processing-based demodulation. In this study, a two-level channel model is proposed to characterize CSK transmission in a single pixel and in the entire image. A general framework of SER analysis for arbitrary CSK constellations was proposed by directly calculating the upper bounds from the empirical distribution of the noise light in the CIE 1931 color space. Through numerical simulations, the influence of the image detector on CSK demodulation was evaluated. The results indicated that an accurate target region is important for maintaining the SER, and an enlarged target region is beneficial when the maximum ratio combination and selective combination algorithms are used in pixel combination.

Recently, visible light communication (VLC) in the industrial Internet of Things has been widely concerned. In these systems, multi-access technologies are always used to eliminate interference between adjacent transmitters, significantly decreasing transmission efficiency. Meanwhile, the attocell boundaries caused by multi-access technologies can also limit communication coverage and lead to frequent receiving switches. To overcome these weaknesses caused by the division of attocell, we design a boundaryless none-attocell VLC system in this paper. In the proposed system, each transmitter uses all available communication resources, and a cubic receiver is adopted to receive in both non-overlapping and overlapping areas. Specifically, we propose a scheme for adaptive signal selection, enabling the receiver to select the recoverable transmitting signals. After that, we introduce an adaptive channel estimation and signal recovery method, which adaptively achieves signal combining and overlapping signal recovery. Our simulations verify the proposed scheme and demonstrate that the proposed system with the adaptive receiving scheme has better error performance and broader communication coverage than the traditional attocell system.

Visible light communication (VLC) has been deemed to be one promising technique for the sixth-generation wireless communication network. However, due to the attenuation properties, the VLC ranges are usually limited. To unlock the advantage of multiple light-emitting diodes (LEDs) and extend the coverage of VLC systems, a relay-aided VLC system with non-orthogonal multiple access (NOMA) is proposed in this paper. Specifically, a decode-and-forward (DF) relay protocol is introduced to construct the relay-aided VLC system with NOMA. Moreover, the closed-form expression of the outage probability (OP) in the DF relay-aided VLC system with NOMA is derived to accurately characterize the theoretical performance of the system. Thereafter, the effects of the corresponding parameters on the OP are investigated. Simulation results verify the accuracy of the derived theoretical expression and illustrate that the DF relay-aided VLC system with NOMA can effectively improve system outage performance. Compared to the direct transmission NOMA VLC system without relay link, our scheme can obtain $\text{15}\,\text{dB}$ transmit signal-to-noise ratio gains in $10^{-3}$ OP level. Last but not least, the optimal transmit semi-angle and deployment height of the relay can be determined for achieving the optimal system outage performance.

Large-scale disaster occurs all over the world frequently, disconnects telecommunications, and destroys communication equipment. In recent years, unmanned aerial vehicles (UAVs) network systems have been studied to work on the reconstruction activities safely and flexibly. The more means of telecommunication, the better because the UAV networks are used for emergency communication. Therefore, this paper studies optical camera communication (OCC) systems using RGB-LED-mounted drones and a high-speed camera for disaster recovery and proposes the RGB-LED-mounted drone’s detection scheme and the signal equalization technique to suppress the RGB interference. We detect the drone using the algorithm of a deep neural network (DNN) based object detection called YOLOv3. This paper adds a new function to reduce the frame rate in object detection. Consequently, the proposed scheme reduces the frame rate to a rate that can conduct real-time operations less than 20 fps from 600 fps. Moreover, the experimental results indicate the feasibility of the proposed scheme that can communicate in error-free operation at a 300-m distance.

We address the lens optimization and signal processing for array-based multiple-input multiple-output (MIMO) visible light communication, especially under link misalignment. We employ one concave lens and one convex lens to separate the lights from different light-emitting diodes (LEDs), and optimize the lens structure to minimize the condition number of channel gain matrix. In this way, the light emitted by different LEDs can be separated well from each other. To further mitigate the interference under transmitter/receiver mobility, we propose two signal processing approaches based on successive interference cancellation (SIC) and multi-layer coding (MC), along with maximum ratio combining (MRC) for interference/signal decoding. It is demonstrated that the interference can be reconstructed and eliminated through SIC, and MC can partially decode the interference to better reconstruct the desirable message. The proposed signal processing approaches can significantly improve the sum rate in both link alignment and misalignment cases. Moreover, MC can achieve higher sum rate, especially in the case of link misalignment.

Optical channel decorrelation is a key aspect in designing a multi-user visible light communication system. As light-emitting diodes (LEDs) are commonly used for illumination and data transmission in such a system simultaneously, the interference between them is a major problem for suitable modulation schemes. We have proposed to position liquid-crystal (LC) matrix elements in front of the receivers in order to block unwanted light – so effectively acting as filter and reducing the interference. To do so, the appropriate pixels of the LC filter are switched either to a transmissive state or to an opaque state. The selection of the correct pixel patterns is a high-order optimization problem, which makes it challenging for classic algorithms. In this paper, we suggest applying a genetic optimization to find suitable pixel patterns. We combine this kind of receiver-side optimization with conventional convex precoding at the transmitter side in an iterative manner. The overall optimization goal is to maximize the sum rate over all users. To prove the effectiveness, we use a numeric ray-tracing simulation with different settings. Also we analyze the impact of the main parameters for the genetic algorithm.