Li-Fi — The Future of Communication Industry
Introduction:
The ever evolving fields of communication has provided it’s users with various technologies over years. The size and complexity of the architecture has been reduced with the introduction of every new technology. Internet has brought a notable change in the fields of communication. Communication over longer distances has been made easier and affordable through the internet. From wired to wireless, internet has been self-evolving since it has been introduced.
Ethernet was the basic foundation for wired internet connection. Ethernet was established on the well-established telephone lines. These lines served as the source for internet. Internet was made available as a wireless network after introducing Wi-Fi technology which relies on radio waves. The next generation technology is in the development phase, in which the data is transferred through light and this is called as Li-Fi (Light Fidelity). In general, Li-Fi is called as Visible Light Communication. Visible Light Communication technology is a modern, emerging technology which is recently very popular in both academia and industry due to rapid advances in production of LED lamps and also due to the high potential of these lamps in creating lighting and sending data simultaneously. [3]
The concept of Li-Fi was introduced by Harald Hass—a German physicist from the University of Edinburgh, UK. He referred it as “data through illumination”. [1][4] This new technology uses LED lights instead of radio waves to transmit data. The LED’s used in Li-Fi will flicker several times a second to transmit data which is not easily identified by a human eye. Li-Fi produces higher data rates than Wi-Fi, it has a data rate of 10 megabits per second and provides better security, bandwidth, availability and efficiency.
The LED lights which are being widely used for lighting purposes can be used as the transmitter for Li-Fi. Image sensors and photodiodes act as receivers in Visible Light Communication (VLC). It can also be used in street lamps which serve as public internet access points to auto-piloted cars that communicate through their headlights. Li-Fi can be a technology for the future where data for laptops, smart phones, and tablets will be transmitted through the light in a room. [2] LEDs provide a respectable modulation potential. This aspect increases the attractiveness of VLC [5].
Functioning of Li-Fi:
The high speed data transmission from the optical network or even a co-axial cable network can be further propagated by using LEDs. The essence of this concept is the seamless transfer of data via the medium of light. [6] An advanced LED, which is more durable and reliable acts as primary transmitter in Visible Light Communication. These next generation LED’s have an advantage of being turned on and off very quickly; this flickering of LED bulb plays a key role in transmitting data. The flickering of LED’s cannot be detected by a human eye. [3] A light sensor like photodiode acts as a receiver of the Li-Fi signal. A device which depends on Visible Light Communication must have a light sensor to receive data.
The working principle of Li-Fi is very simple. It consists of a light emitter on one end and a light sensor on the receiving end. The light sensor receives the data in binary code from the LED. When the LED is turned off, the light sensor at the receiving end registers it as binary bit 0 and when the LED is turned on it registers as binary bit 1. To transmit data, the LED flashes numerous times or use an array of LEDs of few different colors. [3] Data processing is done depending on the number of LEDs used. Data rate is high when we use different types of LED’s. By using proper multiplexing techniques data rate of approximately 100 Gbps can be achieved using high speed LED’s. [9] The data rate can be increased by parallel data transmission using LED arrays where each LED transmits a different data stream.
Advantages of Li-Fi over Wi-Fi:
Unlike radio waves, Visible Light Communication is literally visible to the human eye. So, it is easy to identify the source of data transmission in military applications. Also visible light cannot penetrate through barriers such as walls and other partitions—the transmission of data is confined to a particular region. This is advantageous in applications that require high security. Visible Light Communications is not a health hazard for human body or eyes. LED lighting has recently become part of a building infrastructure, making visible light communication infrastructure is fairly easy by adding communication function to LED lighting. [3]
Future Visions and Applications of Li-Fi:
Emerging Visible Light Communication systems have many prospective novel and challenging applications especially outdoor. [2] Smart lighting systems is one of the major applications of Li-Fi. In environments such as mines and petrochemical plants, Visible Light Communication provides a safe alternative to electromagnetic interference from radio frequency communications. Electronic gadgets like Laptops, tablets, smart phones, etc. can connect with each other directly using Li-Fi. By using visible Light Communications, short range links have better security and very high data rates. Acoustic waves and Radio frequency are used in underwater communication. Due to strong signal absorption in water, RF use is impractical. Acoustic waves have extremely low bandwidth and disturb marine life. Instead Li-Fi can be used for underwater communication.
Li-Fi provides a solution for short-range communications. Li-Fi can be used to reduce weight and cabling and add flexibility to seating layouts in aircraft passenger cabins where LED lights are already deployed. Visible Light Communication can achieve centimeter-level accuracy of indoor positioning at low cost. [10] In-flight entertainment (IFE) systems can also be supported and integrated with passengers’ own mobile devices. One of the important applications which we will focus on in this literature review is Intelligent Vehicular Communication.
Li-Fi in Intelligent Transportation Systems:
Road accidents which cause loss of material and most importantly human lives are becoming severe even with the deployment of many intelligent communication devices on board vehicles and alongside the road. [8] To minimize road accidents and fatalities, various modes of vehicular communications, such as vehicle-to infrastructure (V2I), vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V), are being investigated. [7]. LED-based Visible Light Communication systems can be used in vehicular environments using the well-established infrastructures such as LED-based traffic lights. Visible Light Communication systems can broadcast road traffic safety information, thus helping to minimize the number of road accidents and smoothing traffic flow. Traffic information picked up in real time or prerecorded is processed through the traffic controller. [7] Based upon the signal, the information passes through the Visible Light Communication transmitter system to the traffic light which finally emits the data along with signaling.
Commercialization of Li-Fi:
Visible light communication (VLC) is rapidly emerging as a compelling technology for supplementing traditional radio frequency communication and enabling new wireless device use cases that are uniquely achievable with this technology. Though there are many advantages and applications of Li-Fi it is not easy to establish a Li-Fi network on top of a well-established Wi-Fi network. Wi-Fi network is already pre-established and consumers are adapted to this network. In order to commercialize Li-Fi we need coordination between lighting equipment manufacturers and the device manufacturers. The device manufacturers must incorporate high speed photodiode receivers in their products and the lighting OEM’s must concentrate on improving the longevity of LED’s. Li-Fi could provide lighting OEMs with a new source of revenue by incentivizing their customers to upgrade to Visible Light Communication -enabled lamps and fixtures after they have made the initial upgrade to LED lighting. [10]
Future Takeaways:
The quest for better technology than Wi-Fi has lead human kind to Li-Fi. The concept of Li-Fi has introduced us to a new dimension in the fields of communication. Using light for data transmission is a fascinating idea. The higher data exchange rates and secured data transmission makes Li-Fi an appealing idea. Its ability to provide cost effective intelligent vehicular communication systems is one of the major applications. Research is being conducted to design Li-Fi Communication between automated vehicles to avoid road fatalities. Reliability and cost effectiveness prove that Li-Fi has the prospective to become the future of communication industry. Li-Fi also has its own share of disadvantages like feasibility of larger coverage areas is confined only to open spaces. This is not applicable in closed areas as light cannot travel through barriers like walls. However its applications and advantages over the existing technology make Li-Fi a potential technology for future purposes in the communication industry.
References:
[1] R. Sharma, Raunak and A. Sanganal, ‘Li-Fi Technology – Transmission of data through light’,Int.J.Computer Technology & Applications, vol. 5, no. 1, pp. 150-154, 2014.
[2] S. Haruyama, ‘VISIBLE LIGHT COMMUNICATION USING SUSTAINABLE LED LIGHTS’, ITU Kaleidoscope Academic Conference, 2013.
[3] A. Khosroshahi, ‘ENERGY MANAGEMENT IN BUILDINGS USING VISIBLE LIGHTCOMMUNICATION’, I CTPE-2012, vol. 111, no. 527-531, 2012.
[4] A. Singh and A. Veeraiahgari, ‘Light Fidelity Technology’, IOSRJECE, vol. 9, no. 2, pp. 115-118, 2014.
[5] L. Grobe, A. Paraskevopoulos, J. Hilt, D. Schulz, F. Lassak, F. Hartlieb, C. Kottke, V.Jungnickel and K. Langer, ‘High-speed visible light communication systems’, IEEECommunications Magazine, vol. 51, no. 12, pp. 60-66, 2013.
[6] A. Mishra and N. Salian, ‘Internet using Visible Light Communication’, International Journalof Engineering and Technology, vol. 3, no. 5, pp. 577-581, 2011.
[7] N. Kumar, D. Terra, N. Lourenço, L. N. Alves and R. L. Aguiar, ‘Visible LightCommunications in Intelligent Transportation Systems’, Intelligent Vehicles Symposium Alcalá deHenares, 2012.
[8] N. Kumar, ‘Visible Light Communication Based Traffic Information Broadcasting Systems’,IJFCC, pp. 26-30, 2014.
[9] P. Luo, Z. Ghassemlooy, H. Minh, E. Bentley, A. Burton and X. Tang, ‘Performance analysis of acar-to-car visible light communication system’, APPLIED OPTICS, pp. Vol. 54, No. 7, 2015.
[10] A. Jovicic, J. Li and T. Richardson, ‘Visible light communication: opportunities, challenges andthe path to market’, IEEE Communications Magazine, vol. 51, no. 12, pp. 26-32, 2013.