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Visible Light Communication. By: Suhail More ME-E&TC Rollno-E1109. Under Guidance of: Prof C.V Kulkarni. Contents. Introduction Why VLC Technology Modulation VLC Consortium Applications Difficulties Conclusion and Outlook.
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Visible Light Communication By: Suhail More ME-E&TC Rollno-E1109 Under Guidance of: Prof C.V Kulkarni Visible Light Communication
Contents • Introduction • Why VLC • Technology • Modulation • VLC Consortium • Applications • Difficulties • Conclusion and Outlook Visible Light Communication
Introduction • New communication technology using Visible light. • Visible light is only a small portion of the electromagnetic spectrum. • Wavelength between 380nm(750 THz) to 750nm(428 THz). Visible Light Communication
WHY VLC???? • It does not cause any health problems. • No EM-interference. • It is free. • Fast switching. • Ever-increasing market share of LEDs makes VLC ubiquitously available. Visible Light Communication
Technology(1/3) • Transmitters • Theoretically every kind of light source can be used as transmitting device. • More promising alternatives are fluorescent lights and LEDs. • LEDs are the predominant choice for transmitters. Visible Light Communication
Technology(2/3) • Receivers • Photodiode receivers. • CCD and CMOS sensors. Visible Light Communication
Technology(3/3) Visible Light Communication
Data rates achieved • Phosphorus LEDs can achieve up to 40 Mbps. • By using RGB LEDs data rates can go up to 100 Mbps. • RCLEDs (Resonant Cavity LEDs) can achieve data rates up to 500 Mbps. • RCLEDS use Bragg reflectors to enhance the emitted light. • Increased spectral purity when compared to conventional LEDs. Visible Light Communication
Component Set Up Transmitter unit Receiver unit Visible Light Communication
Modulation • Modulation is used to transform the data(given as a sequence of 0s and 1s) into a series of light pulses. • Two main alternative modulation schemes: • Pulse Position Modulation(PPM): - Amplitude & width of pulse is constant. • Frequency Shift Keying (FSK): - Digital information is transmitted through frequency changes of carrier wave. Visible Light Communication
VL vs RF Comparison Visible Light Communication
VLC Consortium • The Visible Light Communication Consortium was established in 2003 by Japanese tech-companies. • Four Committees: • Research & Planning • Technical • Standardization • Popularization • Two standards are proposed: • JEITA CP-1221 • JEITA CP-1222 • Standardization efforts for physical and media access layer are also done by IEEE 802.15, Task Group 7. Visible Light Communication
Applications • Smart Home Network • Commercial Aviation • Hazardous Environments • Hospital and Healthcare • Defense and Military Applications • Underwater Communications • Indoor location estimation • Vehicle to vehicle communication Visible Light Communication
VEHICLE COMMUNICATION • Many cars have LED lamps. Traffic signage, traffic lights, and street lamps are adopting the LED technology so there are massive applications opportunities here. Visible Light Communication
HOSPITALS & HEALTHCARE • There are advantages for using VLC in hospitals and in healthcare. Mobile phones and Wi-Fi's are undesirable in certain parts of hospitals, especially around MRI scanners and in operating theatres. Visible Light Communication
SMART LIGHTING • Smart buildings require smart lighting. Smart lighting with VLC provides the infrastructure for illumination, control and communications and will greatly reduce wiring and energy consumption within a building. Visible Light Communication
UNDERWATER COMMUNICATIONS • Radio waves do not propagate for a long distance under water. • It was demonstrated that the flashlight visible light transmitter was able to transmit signals for 7 meters distance. Visible Light Communication
Difficulties • Line of sight. • Very high light intensity of other source can cause the sensor to misjudge the light from the original source. • Short range.(max 15 meters) Visible Light Communication
Conclusion & Outlook • VLC is a promising technology even if it is still in a very early stage. • Transmission rates are high as compared to other technology. • Using arrays of LED’s more data transmission can be obtained. Visible Light Communication
References • Komiyama, Kobayashi “Study of visible light communication using RGB LED lights” SICE annual conference 2011 • D. Langer and J. Vucic , “Optical Wireless Indoor Networks: Recent Implementation Efforts,” Proc. ECOC, Torino, Italy, Sept. 2010. • H.Sugiyama, S.Haruyama, M.Nakagawa. “Experimental investigation of modulation method for visible-light communications “2006. • T. Komine and M. Nakagawa, “Fundamental Analysis for Visible-Light Communication System using LED Lights,” IEEE Tranaction on Consumer Electronics, vol. 50, pp. 100–107, February 2004. • D. O’Brien et al.:” Visible Light Communications: recent progress and challenges”, 2008 IEEE. • Ramirez-Iniguez, R. ; Idrus, S. M. ; Sun, Z. (2008) “Optical Wireless Communications : IR for wireless connectivity” CRC Press,USA. • VLCC website ; http://www.vlcc.net Visible Light Communication
THANK YOU Visible Light Communication