lecture 2 vlc
TRANSCRIPT
VLCGhulam Yasin
Let there beLIGHT !!
Let there beLIGHT !!
Existing or Being everywhere at the same time
Universal Connectivity
There is a large range of new opinion on these consideration.
New Idea for the Communication?
Security
Regulation
Eye safety
Health
Power consump-tion
Invisibility
Multimedia
Eavesdrop (regularity)
Frequency restriction
Low price
Human body safe
Eye safety regulation
Low power consumption
Mobility
Ease to use
Using it everywhere
High Speed Invisibility
Price
Convenience
Introduction
Lighting is a major source of electric energy consumption
It is estimated that 1/3 of global consumption of electricity is spent on lighting purposes Fluorescent lampas contain environnemental polluants
– The replacement of Light emitting diodes (LEDs) generating white light will reduce energy consumption It is fortune that White LED (WLEDs) are already
commercially available– Roughly 20 times and 5 times less power than
conventional light source and fluorescent bulbs
VLC ResearchesFirst research can be traced to as early as 1998-1999Contribution addressing broadband VLC using WLEDstarted appearing in 2001 Visible Light Communication Consortium (VLCC)
was established in November 2003– Members includes Toshiba, NEC, KDDI, Sony,
etcIEEE issued a Call for contributions on IEEE
802.15.7VLC in 2009 and held the first meeting
MotivationAbout 10 years ago, researchers came to the realization
that WLED devices could also be used for wireless communication purposes
– LEDs rends to be considerable cheaper than RF– Optical wireless allows easy bandwidth reuse and
improve security– It does not generate RF pollution– Replacing RF device will reduce interference in RFband– RF radiation in hospital, airplane, and mine will bevanished– Large amount energy can be saved
Why WLED?The weakness of conventional wireless
technologiesExpensive license band
Limited license-free band Interference Cost Power consumption Security
VLC (Visible Light Communication)New communication technology using “Visible Light”
Wavelength between ~400nm (750THz) and ~700nm (428THz)
General characteristic Visibility : Aesthetically pleasing
Security : What You See Is What You Send
Unregulated : No regulation in optical frequency
Health : Harmless for human body
Non-interference with other devices
visibleIR UV700nm 400nm100μm
RF3cm1m 1nm
428THz 750THz3THz10GHz300MHz 300PHz
1mm
300GHz
IrDA
TC 48802.15.3c
THzVLC802.11
802.16
VLC Introduction
Schematic Diagram based onWLED modulation
Application Scenario of VLC
Information
Broadcast
SAMSUNG
English
Chinese
Korean
USB dongleUSB dongle
Mobile to Mobile
Mobile to Multimedia
Keyless door entry
ID check E-payment
• Sign Board• E-book• Airplane• ITS(Intellig
ent Transport System)
• Museum• Product
Info.
Peripheral
Interface
Feasibility Test (PDA-PC/PC-PC visible link)
• Information Broadcasting system
Normal function as indication and illumination devices
Can be used as communication devices for transmitting & broadcasting digital information.
Message Board
E-book
Sign BoardITS (intelligent Transport System)
• Distance and Coverage of Transmission - might be improved as all of RGB LEDs could be modulated. Picture source: LED Magazine★
★
Information Broadcasting of VLC
LED application
Economicalefficiency
Back Lighting Mobile Phone
Home applications
digital device
TFT LCD TV
General Lighting
Communication
Display
General Lighting
Task Lighting
Signal Lamp
VLC Mobile to Mobile Infra to Mobile
Exterior, interior display
Sign & Architecture display
LED screen
LED Applications
Application Function
Mobile to
Mobile
Contents-sharing Data transfer
Mobile to
Fixed
File transfer Video streaming M-commerce
Infrastructure to
Mobile
Indoor Navigation Information-broad-
cast
Handheld device, Portable device
CE, Kiosk, Printer
VLC Application
VLC application
BandwidthSecurity
CoverageMobility
IRU
V
780nm
380nm
1nm
100μm
RF
3cm
1m
visi
ble
PeripheralInterface
LAN
Banking
Door Lock
In Plane
Digital Hospital
ITS (Navigation)
SAMSUNG
Sign Board
e-book
VisibleLAN
RFProhibited
InformationBroadcast
Security
E-display
Contents Machine
Optical receiver Receiver consists of
Optical filter Rejects ‘out-of-band’ ambient (background)
illumination (light)noise Lens system or concentrator
Collects and focuses radiation Photodetector (or array of detectors)
Converts optical power to photocurrent Incoherent (disjoint) detection
Preamplifier (or number of preamplifiers) Determines system noise performance
Post-amplifier and subsequent processing
Optical filter
Optical system
Photodetector
Amplifier
Output
Input radiation
Considering Factor
• Network Topology• Centralized network between AP and VL device.• Distributed network between VL devices
• To establish visible light link• Initial network entry• Channel access• Media access control
• Modulation• IM (Intensity Modulation)• Sub-carrier
• Resource management (RM) and QoS• Efficient resource allocation to different connections• Reuse of resources
• Power saving/power control
• Sleep/Idle modes for power saving• Indicate arrival of packets to nodes in power save mode• Buffer management for devices in power save mode• Power control for battery management and bandwidth management
• Mobility (micro mobility) • when the RX moving
Technical Fields to be discussed
Energy-Efficient CommunicationVLC technology has potential in a number of
specialized application areas, including Hospital and healthcareRisky environmentCommercial aviationCorporate and organizational securityWi-Fi spectrum reliefGreen ComputingDefence and military applicationsUnderwater communications