As RF spectrum is immensely crowded, therefore to meet the requirements of the increasing bandwidth is possibly one of the biggest challenges or drawbacks of RF. In healthcare, the RF radiation may cause interference with the operation of some equipment to hospital equipment, therefore owing to shortcomings of RF, the VisibleLight Communications (VLC) technology is an alternative solution since VLC uses the license free light spectrum (380 − 780𝑛𝑚) and free from electromagnetic interference with enhanced security . Recent reports showed that VLC communication systems employing Light Emitting Diodes (LEDs) have been widely adopted and have reached gigabit transmission speed , however the Organic Light Emitting Diode (OLED) is promising area for research due to easy integration and fabrication, wide beam angle, rich colors and flexibility. As the latest development of VLC, OpticalCameraCommunication (OCC) has shown its existence in several applications , hence due to advances in imaging technology and an extension of IEEE 802.15.7 standard for VLC, OCC presents a promising vision of optical communications . The eruption in the usage of smart and advancement in technology over the decade unfolds the capacity of VLC implementation for the smart devices or camera with no hardware modifications , hence the proposed research in this paper comprises of visiblelight and opticalcameracommunication between the OLED screen and image sensor of the camera.
The history of visiblelight communications (VLC) dates back to the 1880s when the Scottish-born scientist Alexander Graham Bellinvented the photophone, which transmitted speech on modulated sunlight over several hundred meters. This pre-dates the transmission of speech by radio. Recently in Keio University, Japan, LEDs are used to transmit videos by visiblelight. A prototype of VLC had been presented by three undergraduate students atUniversidad de Buenos Aires in 1995, resorting to the amplitude modulation of a 532 nm laser diode of 5mW and photodiodes detector. Since then there have been numerous research activities focused on VLC.In 2006, researchers from CICTR at Penn State proposed a combination of power line communication(PLC) and white light LED to provide broadband access for indoor applications.  Data transfer by using the infra-red portion of the spectrum is already afforded. Latest research activities have been concentrated on achieving data transfer concurrently with enlightenment by means of using LED lighting tool. These energy-stingy and cost-effective LED devices are desired to be used for data transfer without using RF signals, especially in short ranges.The idea of illumination and data communication simultaneously by using the same physical carrier is firstly suggested by Nakagawa et al. in 2003 (Nakagawa Laboratory). Their studies [2- 6] pioneered many following research activities. Later on, the Nakagawa Laboratory team worked with the renowned Japan technology firms and they established the Visual LightCommunication Consortium (VLCC). Following, many research activities have been done that the most outstanding is the European OMEGA Project. Eventually, in 2011, IEEE completed the release and visual lightwirelesscommunication gained a global standard with the name 802.15.7- 2011 - IEEE Standard for Local and Metropolitan Area Networks--Part 15.7: Short-Range WirelessOpticalCommunicationUsingVisibleLightUsingVisibleLight . Though a standard of visual lightcommunication has been released in 2011, dominant use of this technology will take further period.
VisibleLightCommunication is trending in today’s world where there is an ever increasing need of band width and fast speed of communication. Usinglight as a communication medium is introduced by Alexander Graham Bell in 1880 with his invention of photo phone, which transmits the voice signal on a modulated sunlight over several hundred of meters . Again with the invention of LED, VisibleLightCommunication technology came into use. VisibleLightCommunication is the embryonic form of wirelesscommunication. The Line of sight between the transmitter and receiver makes the communication possible. The ability of LED to transfer information over light makes it a very good medium of communication. The light we use daily cannot only used for providing light, but also can be used as transmitting medium. Most of the VLC systems used today are unidirectional and we will have bidirectional VLC systems as time progress.
An optical-wirelesscommunication (OWC) model with the generation 60 GHz millimetre wave (mm-wave) is discussed and investigated. This system is proposed to transfer a digital signal with a 320 Mbps data rate by using an opticalsignal over a wireless channel as a part of visiblelightcommunication (VLC) in the fifth generation (5G) for small cell networks. The electrical generation domain has a challenging with the mm-wave; therefore, our model is introduced and examined. The mm-wave and phase modulation are proposed in the opticalwirelesscommunication for the first time. OWC system with 320 Mbps signaltransmission is successfully achieved. In our simulation, the directly modulated laser (DML) is driven by the digital signal; then, the generated opticalsignal is mixed by the phase modulator with 60 GHz mm-wave carrier to result in a phase modulated opticalsignal to be transmitted over the wireless channel. Based on the simulation results, the proposed OWC system is successfully working to transfer a 320 Mbps data rate over 10m wireless channel distance with low BER (10 -5 ) and good Q-Factor (4). The simulation results show that a cost-effective operation with mm- wave for faster transmission. This research ensures a possible optical link with low cost and RF interference.
VLC is arising as an alternative for upcoming generations data transmission technology for short range application. It acts as a contender to the current wirelesscommunication by attaining larger bandwidth and higher data rate.The spectrum range of VLC is 10,000 times greater than RF spectrum and it is unlicensed.It comes under the branch of opticalwirelesscommunication. This communication uses Light Emitting Diode as a transmitter and photodiode or solar panel or a digital camera as a detector in the receiver. Implementation of VLC can be carried out in the two ways, firstly by connecting the signal source into the transmitter optic and then emitted data can be received directly by the optical receiver.
Abstract:- The aim of this paper is to determine the viability of Indoor OpticalWirelessCommunication System. This paper introduces VisibleLightCommunication along with its merits, demerits and applications. Then the main characteristics of VLC system are described, around which the project is designed. Multiple Input-Multiple Output (MIMO) technique is used in the project in order to enhance the data rate of transmission. Instead of using a system of only one LED and one APD, which transmits only one bit at a time, a system of 4 LEDs and 4 APDs is introduced, which increases the data rates by 300% from the previous case. We observe the signal, noise, SNR, BER etc. across the room dimension. Finally, in the last chapter we summarize our results on the basis of MATLAB simulations and propose some modifications to this model that can be implemented in future.
Abstract: With the episodic increase of advancement in technology, wirelesscommunication has become the need of the hour. The rate at which the use of wireless technology is being developed is tremendous. However, with the increase in usage, there has been unfortunately an increase in network complexity. In order to resolve the crisis of radio frequency spectrum, a newly developed technology has been proposed. This technology has been coined as Li-Fi: Light Fidelity. It is a technology, based on VisibleLightCommunication, which is used to transmit signals and data from one system to another with the help of a Led. The paper proposes a transmission system which will be responsible for transmitting audio signals from one system to another with the help of Li-Fi. Here a light emitting diode acts as the Li-Fi transmitter and photodiode acting as a Li-Fi receiver.The spontaneous switching of the Led enables propagation of signals through a wireless channel and is picked up by the receiving photodiode. The photodiode adhering to its functiontransforms the optical signals into electrical signals and therefore original data is retrieved and transferred. Additionally, with proposition to the system, a comparative study has been delineated with the already existing system.The existing system of networking and communications involve Wi-fi. The emergence and usage of Li-fi is necessary because it offers a substantially similar user experience to Wi-Fi except using the light spectrum. It is essential as it will able to meet up the connectivity demands of future as it is able to unlock unprecedented data and bandwidth.
VisibleCommunication is typically implemented using white LED light bulbs. These devices are normally used for illumination by applying constant current through the LED , by fast variations of current , the optical output can be made to vary at extreme high speeds. Unseen by the human eye , , This variation is used to carry high speed data . When signals reach the receiver through the indoor wireless channel, the photodiode will convert the optical signals to electrical ones and the original information will be recovered. The visiblelightcommunication based on LED is a novel developing technique in the opticalwirelesscommunication field .
LiFi is a wirelessoptical networking technology that uses light-emitting diodes (LEDs) for data transmission. LiFi is designed to use LED light bulbs similar to those currently in use in many energy-conscious homes and offices. LiFi data is transmitted by the LED bulbs and received by photoreceptors. Li-Fi technology transmits data at very high speed and is capable of delivering 224GB of data per second. Furthermore, it offers better security as compared to Wi-Fi. Due to its high speed, Li-Fi technology can be widely used in electromagnetic sensitive areas, such as, hospitals, airplanes, and nuclear power plants. Light Fidelity (Li-Fi) is a data transfer technique that uses light. Light is analogous not only to illumination but also to speed. Li-Fi is also much secured since light cannot pass through walls. It uses visiblelight portion of the electromagnetic spectrum to transmit information. Hence the visiblelightcommunication solves the problem of radio frequency congestion. In this project we transmit data and audio through light at very high data rates without use of microcontrollers and its other peripheral devices.
This new technology is known as Light–Fidelity (Li-Fi). It is a short range wirelesscommunication system based on light illumination from LED, and use the visiblelight as a signal carrier instead of traditional RF carrier as in Wi-Fi. Professor Harald Haas coined the term "Light-Fidelity" and set up a private company, called “Pure VisibleLightCommunication”, to exploit that technology. He envisions a future where data for laptops and smart phones are transmitted through the light in a room in a secure way.
VisibleLightCommunication – the name reflects light is visible but it wraps data within itself and makes it invisible to the crowd with normal eyes. So, encapsulation is inherent in characteristics of visiblelight from LED. Light cannot penetrate walls, so physical security is ensured within a confinement – confidentiality unless one is coming with a photodetector in direct line of sight (LoS). Once data transmission starts, no one can change or modify data being transmitted through optical channel which is out-of-band [ 2 ] in nature. Thus integrity can be implemented. And receiver position and receiver ID based data transmission or services ensures authentication of legitimate user. So, full security solution comes in a package without additional encryption, decryption or any other computation complexities. Moreover, to encrypt and decrypt data before transmission and receive respectively need time which increases delay in response. Healthcare is a real time system where instant response and prompt action from care givers e.g. doctors / nurses can save lives of patients in critical condition. So, Secure VisibleLight based WirelessCommunication (S-VLWiC) can be
In this paper the potential of usingvisiblelightcommunication for data transmission to a mobile phone is investigated. A system, consisting of an LED transmitter and the mobile phone camera as a receiver, is presented. A proof-of- concept has been established, demonstrating that the rolling shutter effect can be constructively exploited to achieve data rates multiple times faster than the frame rate using an embedded CMOS camera sensor. As far as future work is concerned, in order to increase the data rate VLC is regarded as a relatively secure communication when compared with other wireless communications. Here, we proposed a light encryption scheme. We proposed an electronic label and sensor system using VLC. Experimental results show that the solar cell is good .In VLC using three sensors the solar cell is Better than other sensors .in this generation speed of data rate is most important factor solar cell is high speed provide it is less expensive.
Visiblelightcommunication (VLC) is a new technology in which illumination and wireless communications are performed simultaneously using the same light source    . The visiblelightsignal radiated from the source is directly received by the photo detector through free space. Usingvisiblelight has several advantages. It does not interfere with conventional radio frequencies, and the signal can only be detected within the area illuminated by the signal beam, and thus it provides safer transmission, by preventing electromagnetic interference or outdoor eavesdropping . To date, light emitting diodes (LEDs) have been used as popular light sources for VLC. LEDs have higher conversion efficiency, longer lifetime, are smaller in size and mechanically stronger than conventional lighting lamps such as incandescent or fluorescent lamps. And, their light intensity is easily controlled by simply adjusting the LED injection current.
Wireless Fidelity uses 2.4-5 GHz radio frequency signal to deliver wireless Internet at our homes, schools, offices and in other public places. Wi-Fi bandwidth is typically limited to 50-100 megabits per second which is a good alternate to speedup the most current used Internet services, but Wi-Fi is not sufficient for transferring large data files like movies, video games and music files etc. in required bandwidth with good speed. Radio frequency technology like Wi-Fi is not the optimal of way of transmission to overcome the problems of good bandwidth and speed. In addition, Wi-Fi may not be the most efficient way to provide good capabilities such as precision indoor positioning and for recognition of gesture. Opticalwireless technologies called visiblelightcommunication which is referred as Li-Fi offers a new solution in wireless technologies in terms of communication with high speed, good bandwidth, flexibility and usability. Li-Fi is now part of the VisibleLight Communications (VLC) PAN IEEE 802.15.7 standard .
The modern research has made the VisibleLightCommunication (VLC) technology, one of the advanced opticalwirelesscommunication technologies, which is green and clean in nature. VisibleLightCommunication, uses visible region (375nm-780nm) and is used as a more secure medium for data transmission. it achieves high data rates as compared to conventional wireless technologies like Wi-Fi, Bluetooth, Wi-max etc. the conventional technologies uses radio waves for communication. To overcome the shortage of bandwidth we can use light to transfer the data which is known as “DATA THROUGH ILLUMINATION”. LED light bulb that varies in intensity is used and it cannot be followed by the naked eye. It is possible to encode various data in the light by varying the light at which the LEDs flicker on and off to give different strings of 1s and 0s.While using mixtures of red, green and blue LEDs to alter the light frequency encoding a different data channel.
Healthcare Wireless systems should be light weight thus offering intelligent communication system ideal for both patients and mass market . Presently, the RF based wireless is the only technology used in EEG or clinical applications, which suffers from lack of the frequency spectrum and electromagnetic interference , which the latter also has adverse effects on patient’s health and the medical equipment especially in RF restricted zones like ICUs. It is well known that RF signal do suffer from multipath induced fading and distortions, which might affect the system performance and the extensive usage of mobiles and electronic devices in RF restricted areas such as ICU might have abnormal have harmful effect on brain signals too. In healthcare applications, due to shortcomings of RF, VLC technology is optimum solution as it is free from electromagnetic interference, eco- friendly, highly secure and reliable [15,16]. Such a green technology could be used for patient monitoring, patient’s data collection and transmission within hospitals as well as at home, and other places without using RF based technologies.
We have proposed and demonstrated a VLC using TDMA optical beamforming to accommodate multiple users in the VLC usingoptical beamforming. TDMA op- tical beamforming is a technique to focus LED light on each different target device in each time slot. Our results have shown that each user device can enjoy the benefit of the optical beamforming during its time slot with the TDMA optical beamforming. The VLC signal amplitude of each channel increases by 5~10 dB, the optical power density of the VLC signal increases by 2~4 dB, and the transmission distance increases from 110 to 200 cm with the TDMA optical beamforming. Since the proposed technique can increase the performance of VLC effi- ciently and does not depend on the electrical modulation formats, it can be widely used in various applications.
The last few decades have seen rapid advances in information and communication technology. We commonly use broadband technology with high-speed Internet connectivity at our homes, offices, and in our mobile devices. The bandwidth and high- capacity requirements due to the increased use of Internet and broadband services have exceeded our expectations in twenty-first century. OpticalWirelesscommunication (OWC) uses optical carrier in the near-infrared (IR) and visiblelight bands (VLC) and is considered a viable solution for realizing very high-speed and large-capacity communication links. It is a line-of-sight communicationusing a laser/LED to transmit the information signal between two transceivers over an unguided channel which may be either the atmosphere or free space. The technology that is used to achieve OpticalWirelessCommunication discussed in this paper is Li-Fi technology.
The VisibleLightCommunication (VLC) refers to the communication technology that uses the air as a transmission medium, utilizes the visiblelight source as a signal transmitter, and the appropriate photodiode as a signal receiving component. In last few years, we have seen a growing research in VisibleLight Communications (VLC), and the idea of using LEDs for both illumination and data communications. The VLC principle is a relatively new approach for optical free space applications. LEDs provide an almost ideal platform for VLC. An LED can emit and receive light at the same time using multiplexing technology.
Abstract. On the basis of analyzing the development status of the wirelesscommunication technique, a new method to analyze the wirelesscommunication reliability is proposed by using the Received Signal Strength Indication (RSSI). A wireless network model based on module CC2530PA is built, which is composed with a coordinator and a few terminal nodes. By analyzing the data received coordinator and sent terminal nodes, the relations of SER, PER and "pseudo-loss" phenomenon whit RSSI are studied, the model of relation between PER and RSSI is built, analyzing the reliability of wirelesscommunication and threshold value of received data via the model. The research results have very high practical value and will promote the development of wirelesscommunication in the future.