Light Fidelity Research Articles

QoE-Driven Optimized Load Balancing Design for Hybrid LiFi and WiFi Networks

The hybrid light fidelity (LiFi) and wireless fidelity (WiFi) networks are regarded as a promising solution for future indoor wireless communication. In this letter, we investigate the traffic load balancing (LB) issue for this hybrid networks. In our design, considering that user terminals (UTs) may have different data rate demands, we utilize the complementary advantages of the wide bandwidth of the LiFi network and the wide coverage area of the WiFi network to serve the UTs. With considerations of the access point heterogeneity and UTs’ quality of experience (QoE) demands for data rate, we then formulate the LB issue as a mixed-integer non-linear programming problem with the aim of maximizing the system throughput under proportional fairness constraints, and propose a distributed optimal algorithm and a simplified suboptimal sequential algorithm to solve it. Simulation results demonstrate that using the presented QoE-driving LB scheme, more UTs are served with higher QoE while maintaining high system throughput and proportional fairness.

High‐density WGM probes generated by a ChG ring resonator for high‐density 3D imaging and applications

AbstractIn this paper, the ultra‐wideband source for light fidelity (LiFi) and high‐density 3D imaging applications is proposed. The system consists of an add‐drop multiplexer. The center ring is formed by the Chalcogenide glass (ChG), which is coupled with two GaAsInP/P side rings. The nonlinear effect within the side rings (phase modulators) is induced in the central ring. The superposition of light signals from side rings generates wider wavelength band, which makes the original input. The output is the set of squeezed light pulses known as whispering gallery mode (WGM) which is generated at the center of the system. Three different input sources are investigated, where the simulated results are comparatively plotted and discussed. The results show that the wavelength of 1.30 μm is the best input source. The output wavelengths band is ranged from 0.7‐3.1 μm, which is suitable for LiFi source and high‐density 3D imaging applications.

Design and implementation of opto-electro decoder using photonic structure: A new application of Li-fi vis-a-vis optical embedded system

An opto-electro decoder is envisaged in this research using the principle of filter and fidelity, where filter deals with an optical grating structure and fidelity are coped with light wave technology via visible communication. Further, the operational principle of filter relays on photonic band gap of the structure which is replicated through reflectance analysis with the help of the plane wave expansion method, where the working of Li-fi technology banks on the combination of the function of Arduino boards via LED and photo detector through hardware implementation which is characterized by the help of MATLAB Simulink model. To sum up, the combination of optical filter and light fidelity leads to an embedded application to figure out the decoding action.

Effects of Sandstorms on Vehicular-to-Road Visible-Light Communication

Abstract Visible light communication (VLC), popularly known as light fidelity (Li-Fi), is a promising alternative to overcome the limitations of radio-wave communication. VLC is a green technology which uses light-emitting diode (LED) illumination to transmit data without needing fibre cables. VLC is applicable for both indoor and outdoor communication. In this study, we investigate the effect of sandstorms on VLC via simulating a vehicular-to-road VLC (V2LC) outdoor application. Sandstorms are a weather phenomenon which frequently occurs in the Arab peninsula and other parts of the world; in this context, researchers have not thus far addressed the effect of sand particles, which absorb and scatter light, on VLC. Our simulation is conducted using MATLAB software (Natick, Massachusetts, U.S.A.), and the results show that the effect of sandstorms on VLC is similar to that of fog and rain as investigated by other researchers. However, sandstorms are also different in terms of the nature of sandstorm particles, with different sizes and refraction indices when compared with rain and fog particles. We also find that high-density-clay sandstorms, among other types of storms, most severely affect VLC communication and limit the transmission range. Other low- and medium-density storms less severely affect VLC while exhibiting a relatively larger communication range.

Analysis of Optical Wireless Communication Systems

Abstract Optical wireless communication is one of the emerging technologies. Over the last few years it has been the growing interests which have some indoor and outdoor applications. The demand for wireless communication has been growing day-by-day. With radio spectrum, there are some problems related to congestion, limitations on bandwidth as the number of users are increasing day-by-day. As a result, optical wireless communication systems are been used which provides high data rates, much higher bandwidth, unregulated spectrum and highly secured networks. In this paper a review is done on optical wireless communication. Various fields and applications are discussed like under water, space, aircrafts, light fidelity (Li-Fi), etc. Different light sources, coding schemes, modulation techniques are discussed. Also some of the challenges are discussed here.

Integrated RF/Optical Wireless Networks for Improving QoS in Indoor and Transportation Applications

Communications based solely on radio frequency (RF) networks cannot provide adequate quality of service for the rapidly growing demands of wireless connectivity. Since devices operating in the optical spectrum do not interfere with those using the RF spectrum, wireless networks based on the optical spectrum can be added to existing RF networks to fulfill this demand. Hence, optical wireless communication (OWC) technology can be an excellent complement to RF-based technology to provide improved service. Promising OWC systems include light fidelity (LiFi), visible light communication, optical camera communication (OCC), and free-space optical communication (FSOC). OWC and RF systems have differing limitations, and the integration of RF and optical wireless networks can overcome the limitations of both systems. This paper describes an LiFi/femtocell hybrid network system for indoor environments. Low signal-to-interference-plus-noise ratios and the shortage bandwidth problems of existing RF femtocell networks can be overcome with the proposed hybrid model. Moreover, we describe an integrated RF/optical wireless system that can be employed for users inside a vehicle, remote monitoring of ambulance patients, vehicle tracking, and vehicle-to-vehicle communications. We consider LiFi, OCC, and FSOC as the optical wireless technologies to be used for communication support in transportation, and assume macrocells, femtocells, and wireless fidelity to be the corresponding RF technologies. We describe handover management-including detailed call flow, interference management, link reliability improvement, and group handover provisioning-for integrated networks. Performance analyses demonstrate the significance of the proposed integrated RF/optical wireless systems.

LIGHT FIDELITY: THE GREEN WI-FI

Light fidelity (Li-Fi) also known as Green Wi-Fi is a new and emerging technology, which is very popular among researchers and scholars. As internet is become a major need of people in this digital era, people are in search of Wi-Fi and hotspots. Li-Fi is the 5G technology which uses the Light Emitting Diodes for data communication through Wi-Fi. It is beneficial for wireless coverage inside a building however Li-Fi is best for high density data coverage within restricted region than the Wi-Fi. This technology provide the relive from radio interferences issues. In this paper we have discussed this new technology with reference to its various aspects like history, design, working and challenges but our main focus is to comparison of Li-Fi with existing technology. The undertaken study is useful for researchers, scholars and academicians.

A Boon to Gold Miners for Fast Data Transmission and Data Confidentiality Using Light Fidelity Technology to Preserve Their Life

A Boon to Gold Miners for Fast Data Transmission and Data Confidentiality Using Light Fidelity Technology to Preserve Their Life

LiFi up-downlink conversion node model generated by inline successive optical pumping

An on-chip-scale, up-down link conversion circuit for electro-optic signals to use in a light fidelity network application is proposed. A system consisting of a loop microring resonator (known as a Panda-ring resonator), is coupled inline to the input of a Mach–Zehnder interferometer (MZI). When the light from that source is input into the system, a fraction of the power is coupled inline through successive pumping and then circulated within the system. By using the most appropriate device parameters, the whispering gallery mode (WGM) of the light, with the inline successive pumping condition, is generated at the resonance condition. The transmitted signals are a combination of the comb and WGM signals and are obtained at the MZI output. The simulation results obtained have shown that a maximum power of 300 mW is achieved from the device. A comb signal, over the spectral band from 1.350–1.750 µm is obtained, with the center wavelength at 1.55 µm. The results show an up-downlink switching speed of is ~ 20 fs is also obtained.

Review on Li-Fi: an advancement in wireless network communication with the application of solar power

Light Fidelity, commonly referred to as Li-Fi is a technology that was introduced by a German physicist called Herald Hass. This technology in its own uniqueness considers the use of light (Light Emitting Diode, LED to be specific) as its medium of delivering high speed communication that complies with standard IEEE 802.15.7 bidirectional communication standard. This optical means of communications is also known as visible light communication. It is safer when compared with Wi-Fi network. This paper will focus on Li-Fi applications, comparison with existing technologies like Wi-Fi and the inclusion of an alternative source of power i.e., solar power, as a means of effectively optimizing on the availability and accessibility of the benefits in places where erratic or total power outage is a common trend.

An overview of outdoor visible light communications

AbstractIn visible light communication (VLC) technology, the outdoor applications are less explored when compared to those indoors. This is due to the fact that: (1) the dual use of light‐emitting diodes is not always practicable in the outdoor VLC environment; (2) the level of interference and noise is considerably higher in outdoor VLC; (3) many other communication technologies are available to be used which, due to their specific characteristics, adapt better to the outdoor environment when compared to VLC technology. Nevertheless, several outdoor VLC applications have been identified. They include and are not limited to building‐to‐building, vehicle‐to‐vehicle, and road‐to‐vehicle communications. Deploying light fidelity (Li‐Fi) using street and park lights is also feasible. Finally, some applications exploit the ability of solar panels to simultaneously harvest the electrical energy and serve as a VLC receiving antenna. The implementation of these communication systems faces lots of challenges. Most of them are related to environmental factors such as fog, rain, sunlight, haze, snow, dust, and atmospheric disturbances. Some challenges are based on parameters such as the geometrical aspect of the light diffusion, which is Lambertian in most cases. These challenges contribute to lower interest in outdoor VLC to date. However, the environment presents several opportunities. In this article, we explore the outdoor VLC environment, review, and present some promising applications selected from the literature. Furthermore, we underline likely research opportunities based on the actual state‐of‐the‐art and our outdoor VLC characterization experiments.

EH-HL: Effective Communication Model by Integrated EH-WSN and Hybrid LiFi/WiFi for IoT

Technological advances over the last decade in the field of wireless communications have resulted in the improvement of small and low cost sensor nodes outfitted with wireless communication abilities capable of establishing wireless sensor network (WSN). Due to the expansion of Internet of Things (IoT), there are many areas in IoT application where WSN applications are found. These applications generally impose severe constraints on the lifetime of the WSN, which is expected to last several years. It is necessary to diminish the overall energy consumption of the sensor node and to find an additional source of energy for achieving this objective. On the other hand, due to the imminent crisis of the radio frequency spectrum, light fidelity (LiFi) offers many key benefits and effective solutions for these issues that have been postured in the most recent decade. In this paper, we propose a novel EH-HL model for future smart homes and industries based on the integration of energy harvesting WSN (EH-WSN) and hybrid LiFi/WiFi communication techniques. The proposed model is capable of efficiently transmitting data at high speed for bidirectional multidevice and by harvesting energy, we provide the power to the sensor nodes. To synchronize multidevice transmissions, transmit data and provide low-cost wireless communication, we used the color beams of the red, green, and blue LEDs. The result of the evaluation shows that the hybrid communication scheme is proposed in the EH-HL model. It also offers superior performance and achieves a data rate of 25 Mb/s for multiaccess/multiusers.

On-chip electro-optic multiplexing circuit using serial microring boxcar filters

© 2018 The Authors We propose a new variant of electro-optic multiplexing scheme using the boxcar filter arrangement. The circuits consist of multistage add-drop multiplexers that can offer external input-output connections. Input from a single light source can be fed into the system through the input port or through the free-space from light fidelity (LiFi) node. The light signal is fed into boxcar filters and the roll-off bands are obtained. The output of the circuits is formed at the drop, through and the whispering gallery mode (WGM) node of the circuit output. By using the electro-optic conversion in Si-Graphene-Au layer stack, time division (TDM), wavelength division (WDM), frequency division multiplexing (FDM) can be performed. The simulations have shown that a combination of 7 roll-off bands with the maximum spectral widths or bandwidths of ∼6.09 µm or ∼7.63 THz can be obtained.

Analysis of visible light communication (VLC)for biomedical application

In the visible light communication (VLC), light emitting diodes (LEDs) are used as transmitters; the air is the transmission medium and the photodiodes are used for receivers. This is often referred to as light fidelity (Li-Fi). In this method, provide the methodology to evaluate the performance of VLC hotspot networks in the context of data downloading on the move scenarios by using throughput-distance relationship models. In this context, firstly, study the different properties of optical transceiver elements, noise sources, characterization interference, and different link topologies and then introduce the throughput-distance relationship model. Secondly, the analytically based throughput-distance relationship has been developed for evaluating the performance of VLC hotspot networks in indoor environment in both day and night conditions. Simulation results reveal that background noise has a significant impact on the performance of VLC hotspots. As expected, in both indoor and outdoor environments VLC hotspot performs better at night than during the day. The performance of VLC hotspot networks is also quantified in terms of received file size at different bit error rate requirements and velocities of the mobile user.

On-chip remote charger model using plasmonic island circuit

Abstract We propose the remote charger model using the light fidelity (LiFi) transmission and integrate microring resonator circuit. It consists of the stacked layers of silicon-graphene-gold materials known as a plasmonic island placed at the center of the modified add-drop filter. The input light power from the remote LiFi can enter into the island via a silicon waveguide. The optimized input power is obtained by the coupled micro-lens on the silicon surface. The induced electron mobility generated in the gold layer by the interfacing layer between silicon-graphene. This is the reversed interaction of the whispering gallery mode light power of the microring system, in which the generated power is fed back into the microring circuit. The electron mobility is the required output and obtained at the device ports and characterized for the remote current source applications. The obtained calculation results have shown that the output current of ∼2.5 × 10−11 AW−1, with the gold height of 1.0 µm and the input power of 5.0 W is obtained at the output port, which is shown the potential application for a short range free pace remote charger.

Rapid Development of System-on-Chip (SoC) for Network-Enabled Visible Light Communications

<p class="0abstract">Visible Light Communication (VLC) is an emerging optical communication technology with rapid development nowadays. VLC is considered as a compliment and successor of radio-frequency (RF) wireless communication. There are various typical implementations of VLC in which one of them is for exchanging data TCP/IP packets, thus the user can browse the internet as in established Wireless fidelity (Wi-Fi) technology. Briefly, we can call it by Light fidelity (Li-Fi). This paper described the design and implementation of System-on-Chip (SoC) subsystem for Li-Fi application where the implemented SoC consists of hardware (H/W) and software (S/W). In the H/W aspect, Physical Layer (PHY) is made by using UART communication with Ethernet connection to communicate with Host/Device personal-computer (PC). In the S/W aspect, Xillinux operating system (OS) is used. The H/W- as well as S/W-SoC, are realized in FPGA Zybo Zynq-7000 EPP development board. The functional test result shows (without optical channel or Zybo-to-Zybo only) that the implemented SoC is working as expected. It is able to exchange TCP/IP packets between two PCs. Moreover, Ethernet connection has bandwidth up to 83.6 Mbps and PHY layer <em>baud rate</em> has bandwidth up to 921600 bps.</p>

Design of a 2.2-mW 24-Mb/s CMOS VLC Receiver SoC With Ambient Light Rejection and Post-Equalization for Li-Fi Applications

This paper presents an energy-efficient visible light communication (VLC) receiver system-on-a-chip (SoC) that employs ambient light rejection (ALR) and post-equalization techniques for emerging light fidelity (Li-Fi) applications using ordinary phosphorescent white light-emitting diodes (LEDs). A current-reuse transimpedance amplifier is proposed for energy-efficient applications. An ALR unit is implemented to eliminate the potential DC interference under strong ambient light. A two-stage continuous-time linear equalizer is utilized to compensate for the limited bandwidth of white LEDs, which is below 3 MHz. Implemented in a 0.18 μm CMOS process, the receiver occupies an area of 0.7 × 0.4 mm2 and consumes 2.2 mW of power at 24 Mb/s from a 1.8 V power supply. An IEEE 802.15.7 PHY-II compliant Li-Fi link that employs the proposed receiver SoC and a custom transmitter SoC is demonstrated based on 1-W phosphorescent white LEDs without using blue filtering, achieving a bit error rate of 1 × 10−9 for data rates up to 24 Mb/s over 1.6 m distance, and 22 Mb/s over 2.7 m distance, with on–off keying modulation and 211−1 pseudorandom binary sequence (PRBS-11) optical inputs. The receiver SoC achieves a bit efficiency six times better than that of the prior art using off-the-shelf discrete components, and can tolerate an ambient light level of 3500 lx. A figure of merit accommodating the most important system parameters is also proposed for a comprehensive comparison of different VLC systems.

Plasmonic op-amp circuit model using the inline successive microring pumping technique

The electro-optic power pumping system model using the inline successive technique within the modified add-drop filter is proposed. A pumping system consists of a closed loop Panda ring resonator, from which the optical power is coupled inline into the system. By controlling the two side phase modulators, the whispering gallery mode (WGM) is generated by the amplitude-squeezed light within the modified add-drop filter. By using the proposed circuits, the low current can be applied into the system via a gold layer connection, from which the amplified output current can be obtained at the throughput port, which can be functioned as the electronic operational amplifier (op-amp). In application, the WGM output is the amplified signal that can be used for the up (down) link in free space communication network called light fidelity (LiFi). The electro-optic signals conversion can be performed by the stacked layers of silicon–graphene–gold materials. The results obtained have shown that large gain is obtained at the WGM output, which is ~ 5 × $$10^{ - 6}\; {\text{cm}}^{2} \;({\text{V}}\;{\text{sW}})^{ - 1}$$ , when the pumping saturation time is ~ 2 fs. It concludes the suitability of our proposed model for light fidelity, LiFi up-down link conversion.

The Technology of LiFi: A Brief Introduction

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 evolve to overcome the rate speed in WiFi, while using LiFi the rate speed can reach until 14 Gbps. This paper presents an introduction of the LiFi technology including the architecture, modulation, performance, and the challenges. The result of this paper can be used as a reference and knowledge to develop some of the LiFi technology.

Designing of Cell Coverage in Light Fidelity

The trend of communication has changed and the internet user demands to have higher data rate and secure communication link. Wireless-Fidelity (Wi-Fi) that uses radio waves for communication has been used as an internet access methodology for many years. Now a new concept of wireless communication is introduced that uses visible light for communication and is known as the Light-Fidelity (Li-Fi). Li-Fi attracted the researchers for its vast advantages over Wi-Fi. Wi-Fi is now an integral part of everyday life. In near future, due to scarcity of spectrum, it would be quite difficult to accommodate new users in limited spectrum of Wi-Fi. To overcome this, Li-Fi is a good option because of its infinite spectrum range, as it uses the visible range of the spectrum. Many researchers discussed that Li-Fi is secure when compared to Wi-Fi. But is it really secure enough? Can anybody access hotspot of Li-Fi? Or is there a need to develop a technique that is used to block the unauthorized access? In this research work, a cellular concept is introduced for the Li-Fi usage in order to increase the security. This research presents a flexible and adjustable cell structure that enhances the security of Li-Fi. The coverage area is shown by utilizing the geometrical structure of the cone and the area of the cone can be controlled. A mechanical system is also installed on the roof to control the coverage area of a Li-Fi by moving LED bulb slightly up and down. A mathematical expression for the proposed coverage area of the cell is provided, which is formed on the ground level by a beam of light originating from the source of light. The adjustable and controlled structure provides security benefits to the owner. Finally, the research is backed by its simulation in Matlab.