Light Fidelity Research Articles

QoS-Driven Load Balancing in Hybrid LiFi and WiFi Networks

This work studies the quality of service (QoS) performance of wireless networks that integrate light fidelity (LiFi) and wireless fidelity (WiFi). While the hybrid network is potential for improving network capacity, load balancing becomes essential and challenging due to the nature of heterogeneous access points (APs). A number of studies have been conducted to address this issue, focusing on maximising the network capacity with user fairness constraints. However, in practice, QoS metrics including packet loss ratio and latency are important to network services. In this paper, QoS-driven load balancing is studied for hybrid LiFi and WiFi networks (HLWNets) in two scenarios: single-AP association (SA) and multi-AP association (MA). In each case, an optimisation problem is formulated to minimise the packet loss ratio and latency, and a low-complexity iterative algorithm is proposed to solve the problem. Results show that the novel methods, especially MA, can effectively balance the traffic loads among the APs and improve the QoS performance. In addition, the more subflows the better performance MA provides. Targeting the same level of QoS, MA can achieve a system throughput up to 160% higher than the signal strength strategy and 130% higher than the proportional fairness load balancing.

Wireless Information Transfer using Laser

Light Fidelity is a modern technology known as Li-Fi. Wireless services are increase in demand, the availability of the RF spectrum is limited in range. To overcome this light Fidelity come into picture. that uses visible light as a source of communication. Li-Fi is the most resourceful recent development. To transmit data in the visible light spectrum laser diodes are used. Increased accessible spectrum, higher speed, efficiency, security, low latency are the advantages compared to WiFi in this technology. The main of this research paper is to design a Li-Fi transceiver using Arduino which is able to transmit digital data. The hardware has been designed using Proteus design tool (version 8). The software coding is done by using C program. Image and video signals is carried out on the transceiver for enhancing transmission and reception of text. In this work a transceiver is designing that works by using visible light spectrum and low cost components.

Design of Solar Panels for Light Fidelity (Li-Fi)

Light-fidelity(Li-Fi) has become a revolutionary technology in this modern era of wireless communication systems. Li-Fi is based on IEEE 802.15.7 standard and having long spectrum with wavelength of the signals ranges from 380 to 780 nm. As bandwidth of the radio electromagnetic spectrum is becoming more saturated and facing shortage which is a very alarming situation for the engineers working in wireless communication technology. This issue can be resolved using Li- Fi instead of wireless-Fidelity (Wi-Fi) for wireless internet. One of the major advantages of Li-Fi is, it has low initial cost with increased data rate. Moreover, there are certain places where we cannot use Wi-Fi like in air space, petrol stations, nuclear reactor etc. Li-Fi tackle such issues and now we can use internet anywhere and anytime with much larger speed. To use internet without interruption, Li-Fi requires low cost and continuous power supply. In this paper, we propose an alternate power solution for Li-Fi using a free natural source that is a sunlight. Utilizing the proposed solution, one can enjoy internet continuously without power interruption for the low cost of electricity.

LiFi through Reconfigurable Intelligent Surfaces: A New Frontier for 6G?

Light fidelity (LiFi), which is based on visible-light communications (VLC), is celebrated as a cutting-edge technological paradigm that is envisioned to be an indispensable part of 6G systems. Nonetheless, LiFi performance is subject to efficiently overcoming line-of-sight (LoS) blockage, whose adverse effect on the reliability of wireless reception becomes even more pronounced in highly dynamic environments, such as vehicular applications. Meanwhile, reconfigurable intelligent surfaces (RISs) have recently emerged as a revolutionary concept that transforms the physical propagation environment into a fully controllable and customizable space using a low-cost, low-power approach. We anticipate that the integration of RISs into LiFi-enabled networks will not only support blockage mitigation but will also provision complex interactions among network entities, and is hence manifested as a promising platform that enables a plethora of technological trends and new applications. In this article, for the first time in open literature, we set the scene for a holistic overview of RIS-assisted LiFi systems. Specifically, we explore the underlying RIS architecture from the perspective of physics and present a forward-looking vision that outlines potential operational elements supported by RIS-enabled transceivers and environments. Finally, we highlight major associated challenges and offer a look ahead toward promising future directions.

26 Gbit/s LiFi System With Laser-Based White Light Transmitter

Wedemonstrate a high-speed light fidelity (LiFi) communication system deploying ultra-high brightness laser-based white light illumination sources in a surface mount device (SMD) packaging platform. The LiFi transmitter SMD source provides 450 lumens of white light output with a brightness of 1000 cd/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in a dual wavelength configuration comprising blue and infrared (IR) emitting laser diodes within the SMD. First, we present high-speed data transmission beyond 25 Gbit/s over a 3 meter channel distance with the combined data rates from the blue and IR lasers in the single SMD. Next, we present a 2.8 Gbit/s data rate with the dual wavelength laser SMD light source using a side-emissive fiber as the transmitter. This work proves the viability of LiFi systems deploying laser-based white light sources operating at very high data rates with the visible light and communication signal delivered in conventional free-space transmission architectures along with novel configurations using side-emitting fibers.

Hybrid NOMA-based ACO-FBMC/OQAM for next-generation indoor optical wireless communications using LiFi technology

Light fidelity (LiFi) has successfully achieved high data transfer rates, high security, great availability, and low interference. In this paper, we propose a LiFi system consisting of a combination of non-orthogonal multi-access (NOMA), asymmetrically-clipped optical (ACO), and filter bank multicarrier (FBMC) techniques combined with offset quadrature amplitude modulation (OQAM). The paper also applies a mu -law companding approach for a high peak to average power ratio (PAPR) reduction of the FBMC/OQAM scheme. The combination of NOMA, ACO-FBMC/OQAM, and mu -law companding allows a significant increase in throughput and a significant reduction in unserved users. Considering two scenarios, an appropriate algorithm is developed to maximize the throughput and minimize the number of blocked (unserved) users. The results show that the overall system throughput could be increased by 1.8 compared to FBMC, OFDM, and OFDM-NOMA. Furthermore, the proposed system reduces the number of unserved users below 10%, while the system can provide 30 or 60% in case only OFDM-NOMA, FBMC, or OFDM is applied.

Distributed MEMS Sensors Using Plasmonic Antenna Array Embedded Sagnac Interferometer

A micro Sagnac interferometer is proposed for electron cloud distributed sensors formed by an integrated (micro-electro-mechanical systems) MEMS resonator structure. The Sagnac interferometer consists of four microring probes integrated into a Sagnac loop. Each of the microring probes is embedded with the silver bars to form the plasmonic wave oscillation. The polarized light of 1.50 µm wavelength is input into the interferometer, which is polarized randomly into upstream and downstream directions. The polarization outputs can be controlled by the space–time input at the Sagnac port. Electrons are trapped and oscillated by the whispering gallery modes (WGMs), where the plasmonic antennas are established and applied for wireless fidelity (WiFi) and light fidelity (LiFi) sensing probes, respectively. Four antenna gains are 2.59 dB, 0.93 dB, 1.75 dB, and 1.16 dB, respectively. In manipulation, the sensing probe electron densities are changed by input source power variation. When the electron cloud is excited by the microscopic medium, the change in electron density is obtained and reflected to the required parameters. Such a system is a novel device that can be applied for brain-device interfering with the dual-mode sensing probes. The obtained WGM sensors are 1.35 µm−2, 0.90 µm−2, 0.97 µm−2, and 0.81 µm−2, respectively. The WGMs behave as a four-point probe for the electron cloud distributed sensors, where the electron cloud sensitivities of 2.31 prads−1mm3 (electrons)−1, 2.27 prads−1mm3 (electrons)−1, 2.22 prads−1mm3(electrons)−1, and 2.38 prads−1mm3(electrons)−1 are obtained, respectively.

LIFI COMMUNICATION SYSTEM USING KEYPAD

Over the years, the overdependence on Wireless Fidelity (Wi-Fi) for data transmission necessitated the need for an alternate and more reliable means of communication, hence, Light Fidelity (Li-Fi). It involves the use of Light Emitting Diode to transmit data by blinking (i.e. switching them on and off) at a speed not noticeable to the eye. This paper proposed the development of the Li-Fi system using off the shelf electronic components. This would make the system an indispensable means of communication in the nearest future. This data transmission system is different from those in existence because expensive components were not in the design, invariably reducing the overall cost of the implementation. Keywords: Light Fidelity (Li-Fi), Wireless Fidelity (Wi-Fi) Optical communication, Telecommunication

Sequential Load Balancing for Link Aggregation Enabled Heterogeneous LiFi WiFi Network

Light fidelity (LiFi) is one of the promising communication technology for 6G internet of everything (IoE), however, it requires a line-of-sight (LoS) link; in contrast, WiFi can support moderate data rates even in the absence of LoS. As the electromagnetic spectrums of LiFi and WiFi do not overlap, these technologies can be used for concurrent communication, thus, resulting into a link aggregation (LA) enabled heterogeneous LiFi WiFi networks (HLWN). However, for the most efficient utilization of a LA enabled HLWN, proper load balancing is essential. Therefore, in this paper, we propose a novel sequential load balancing method with reinforcement learning (RL)-based access point (AP) assignment followed by optimum resource allocation for LA enabled HLWN. It is observed that the proposed method outperforms the baseline received signal strength (RSS) scheme by around 37% and 56% in terms of average data rate and user satisfaction, respectively. Furthermore, the proposed method performance closely matches to the exhaustive search with the added advantage of reasonably low complexity. Additionally, the robustness of the proposed method is proven by considering two different user’s mobility models in this work.

INSPIRE-SAT 7, a Second CubeSat to Measure the Earth’s Energy Budget and to Probe the Ionosphere

INSPIRE-SAT 7 is a French 2-Unit CubeSat (11.5 × 11.5 × 22.7 cm) primarily designed for Earth and Sun observation. INSPIRE-SAT 7 is one of the missions of the International Satellite Program in Research and Education (INSPIRE). Twice the size of a 4 × 4 Rubik’s Cube and weighing about 3 kg, INSPIRE-SAT 7 will be deployed in Low Earth Orbit (LEO) in 2023 to join its sister satellite, UVSQ-SAT. INSPIRE-SAT 7 represents one of the in-orbit demonstrators needed to test how two Earth observation CubeSats in orbit can be utilized to set up a satellite constellation. This new scientific and technological pathfinder CubeSat mission (INSPIRE-SAT 7) uses a multitude of miniaturized sensors on all sides of the CubeSat to measure the Earth’s energy budget components at the top-of-the-atmosphere for climate change studies. INSPIRE-SAT 7 contains also a High-Frequency (HF) payload that will receive HF signals from a ground-based HF transmitter to probe the ionosphere for space weather studies. Finally, this CubeSat is equipped with several technological demonstrators (total solar irradiance sensors, UV sensors to measure solar spectral irradiance, a new Light Fidelity (Li-Fi) wireless communication system, a new versatile telecommunication system suitable for CubeSat). After introducing the objectives of the INSPIRE-SAT 7 mission, we present the satellite definition and the mission concept of operations. We also briefly show the observations made by the UVSQ-SAT CubeSat, and assess how two CubeSats in orbit could improve the information content of their Earth’s energy budget measurements. We conclude by reporting on the potential of future missions enabled by CubeSat constellations.

Learning Indoor Environment for Effective LiFi Communications: Signal Detection and Resource Allocation

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.

An Adaptive Handover Scheme for Hybrid LiFi and WiFi Networks

The hybrid light fidelity (LiFi) and wireless fidelity (WiFi) network (HLWNet) is considered to be a potential component of the next generation indoor wireless networks. However, due to the susceptible line-of-sight propagation of optical signal and the ultra-dense deployment of LiFi access points, the handover problem in the HLWNet becomes challenging and it is hard to design a handover scheme that adapts to complex indoor working scenarios. In this paper, we propose a novel handover scheme, in which the handover events in HLWNet are classified into three categories and a particular strategy for each category is applied to calculate the optimal dwell time in the handover procedure. The proposed handover scheme is adaptive to different working situations, since the information about multiple attributes, such as channel quality, user velocity, and arrivals data rate, is gathered to make the handover decision and to calculate the dwell value. The simulation results show that, compared to the benchmarks, the proposed method is able to increase the user throughput by around 65%, decrease the handover rate by up to 80%, and reduce the packet delay by up to 57%. In addition, the proposed method significantly improves the robustness performance of user throughput and handover rate under different scenarios.

An Artificial Neural Network-Based Handover Scheme for Hybrid LiFi Networks

Combining the ultra-high user throughput of the light fidelity (LiFi) and the ubiquitous coverage of wireless fidelity (WiFi), the hybrid LiFi and WiFi network (HLWNet) demonstrates unparalleled advantages in indoor wireless data transmission. Due to the line-of-sight propagation nature of the optical signal, the handover decision making problem in HLWNets, however, becomes more critical and challenging than that in previous heterogeneous networks. In this paper, the handover decision making problem in the HLWNet is regarded as a binary classification problem, and an artificial neural network (ANN)-based handover scheme is proposed. The complete handover scheme consists of two sets of ANNs that use the information about channel quality, user movement, and device orientation as input features to make handover decisions. After being trained with the labelled datasets that are generated with a novel approach, the ANN-based handover scheme is able to achieve over 95% handover accuracy. The proposed scheme is then compared with benchmarks under an indoor simulation scenario. The simulation results show that the proposed approach can significantly increase user throughput by 20.5-46.7% and reduce handover rate by around 59.5 - 78.2% as compared with the benchmarks; in the meanwhile, it maintains a great robustness performance against user mobility and channel variation.

Design and Implementation of Light Fidelity Communication Systems

Design and Implementation of Light Fidelity Communication Systems

IDim: Practical Implementation of Index Modulation for LiFi Dimming

This paper introduces a novel dimming method for Light Fidelity (LiFi) based on a time-domain sample index modulation (TIM), called indexed dimming (iDim). The aim is to provide a wide brightness range, while maintaining a high signal-to-noise ratio (SNR) performance and a high transmission rate. Direct current optical orthogonal frequency division multiplexing (DCO-OFDM) is used and novel line codes are presented. The system performance is experimentally validated by an implementation on a NI PXIe-1085 and NI-7966R Field Programmable Gate Array (FPGA). Implementation results show that the proposed iDim jointly offers multiple benefits compared to existing dimming methods such as amplitude modulation (AM) dimming. Specially, the lowest optical power of the iDim method is measured at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20~\mu \text{W}$ </tex-math></inline-formula> , which is 10 times lower than the measured limit of AM dimming. The iDim system provides a SNR of 22.5 dB for all brightness levels, while the AM-dimming method dramatically reduces its SNR when light is dimmed. The transmission rate of iDim is also higher than DCO-OFDM. This results in up to 40% reduced optical power per bit when compared to sDim, a pulse-width-modulation (PWM)-inspired dimming method. Therefore, iDim is a promising dimming method for applications targeting extremely low illumination levels.

A Review on Li-Fi: The Next Generation Wi-Fi

Abstract: The Li-Fi stands for Light Fidelity. The technology is very new and was proposed by the German physicist Harald Haas in 2011 TED (Technology, Entertainment, Design) Global Talk on Visible Light Communication (VLC). Light Fidelity (LiFi) is a Visible Light Communication (VLC) based technology that making a light as a media of communication replacing the cable wire communication. LiFi is evolved to overcome the rate speed in Wi-Fi, while using LiFi the rate speed can reach until 14 Gbps. This paper includes an introduction of the LiFi technology including the architecture, working, performance, and the challenges Li-Fi, its applications, features and comparison with existing technologies like Wi-Fi etc. Wi-Fi is of major use for general wireless coverage within building, whereas Li-Fi is ideal for high density wireless data coverage in confined area and especially useful for applications in areas where radio interference issues are of concern, so the two technologies can be considered complimentary. Keywords: LED, Li-Fi Technology, Wi-Fi Technology, Data Transmission, Visible Light, Li-Fi Applications

Machine learning for DCO-OFDM based LiFi

Light fidelity (LiFi) uses different forms of orthogonal frequency division multiplexing (OFDM), including DC biased optical OFDM (DCO-OFDM). In DCO-OFDM, the use of a large DC bias causes optical power inefficiency, while a small bias leads to higher clipping noise. Hence, finding an appropriate DC bias level for DCO-OFDM is important. This paper applies machine learning (ML) algorithms to find optimum DC-bias value for DCO-OFDM based LiFi systems. For this, a dataset is generated for DCO-OFDM using MATLAB tool. Next, ML algorithms are applied using Python programming language. ML is used to find the important attributes of DCO-OFDM that influence the optimum DC bias. It is shown here that the optimum DC bias is a function of several factors including, the minimum, the standard deviation, and the maximum value of the bipolar OFDM signal, and the constellation size. Next, linear and polynomial regression algorithms are successfully applied to predict the optimum DC bias value. Results show that polynomial regression of order 2 can predict the optimum DC bias value with a coefficient of determination of 96.77% which confirms the effectiveness of the prediction.

A Review on LiFi Network Research: Open Issues, Applications and Future Directions

This paper extensively reviews and analyses Light Fidelity (LiFi), a new technology that uses light to transmit data as a high-speed wireless connection system from a wide spectrum of domains. An in-depth analysis and classifications of pertinent research areas for LiFi networks are presented in this paper. The various aspects constituting this paper include a detailed literature review, proposed classifications, and statistics, which further is deliberated to encompass applications, system architecture, system components, advantages, and disadvantages. LiFi and other technologies are compared, multi-user access techniques used in LiFi networks are investigated and open issues are addressed in detail. The paper is concluded with a comprehensive taxonomy of literature comparison that has served as the basis of the proposed open issues and research trends.

TEXT AND VIDEO COMMUNICATION USING Li-Fi TECHNOLOGY

Traditionally communication has been done using radio waves, and due to this shortage there is an increasing need to look for different avenues and means for communication and therefore communication using visible light spectrum is a very promising prospect to address the situation. Li-Fi (Light Fidelity) is often used to describe high speed Visible Light Communication (VLC). VLC is dedicated to resolving the problem of lighting and communication in tandem. In our project, we aim to develop a prototype of Visible Light Based Communication link. The project consists of a transmitter, a LED, which transmits the text and video which is received by the receiver.

Paradigm Shift from 1G to 5G Technology: A Comparative Study

Now-a-day technology is evolving on a large scale. Primarily when the technology of mobile phones came into existence, a wireless technology came into being. This was the 1G technology that was trending. Further as the need for technology started increasing, 1G(first generation) technology got evolved to 2G(second generation), later on 3G,4G as per the need and now currently to 5G technology which makes use of lifii.e light fidelity which uses light as a source of transmitting data from source to destination. Mobile wireless technology is growing from one generation to other in terms of data rate, bandwidth, internet services, and with many more factors. This paper contains the information about how the transition took place from 1G to 5G network over time. Also the paper contains the reasons of why this transition took place, the importance of each generation and a few use cases of those generations.