July 2009 doc.: IEEE 802.15 09-0550-00-0007 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Physical Layer proposal outline] Date Submitted: [July. 15. 2009] Source: [Taehan Bae, Hyuk-Choon Kwon, Jaeseung Son, Ying Li, Sridhar Rajagopal, Farooq Khan] Company [Samsung Electronics Co.,LTD] Address [Dong Suwon P.O. Box 105, 416 Maetan-3dong, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-742 Korea] Voice:[82-31-279-7293], FAX: [82-31-279-5130], E-Mail:[[email protected]] Re: [] Abstract: [PHY layer proposal outline is described in this document. Some consideration point of proposal is also presented.] Purpose: [Contribution to IEEE 802.15.7 TG-VLC] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. TG-VLC Submission Slide 1 Taehan Bae et al., Samsung
July 2009 doc.: IEEE 802.15 09-0550-00-0007 Physical Layer proposal outline 2009. 07 Samsung Electronics TG-VLC Submission Slide 2 Taehan Bae et al., Samsung July 2009 doc.: IEEE 802.15 09-0550-00-0007 Outline Samsung PHY considerations Proposal scope Block Diagram of VLC System Band Plan Guard Color Considerations of Modulation for VLC Summary
TG-VLC Submission Slide 3 Taehan Bae et al., Samsung July 2009 doc.: IEEE 802.15 09-0550-00-0007 Samsung PHY considerations PHY considerations based on Current TCD Data rate High data rate 1~100Mbps Distance Short range <= 3m Device characteristic of light source (& receiver) Divergence angle: 10 degree ~ 30 degree (high data rate) FOV: 10 degree ~ 30 degree (high data rate) Visibility support TG-VLC Submission
Slide 4 Taehan Bae et al., Samsung July 2009 doc.: IEEE 802.15 09-0550-00-0007 Proposal scope Scope based on the classification of VLC Mobile to Mobile (1:1 communication) Full duplex ~100Mbps Distance: 1m Infrastructure to Mobile (1:N comm.) Visible LAN (1:N, N is limited) Full duplex Distance: 3m Information broadcasting (1:N comm.) Uni-direction Distance: 3m Support WDM TG-VLC Submission Slide 5
Taehan Bae et al., Samsung July 2009 doc.: IEEE 802.15 09-0550-00-0007 Block Diagram of VLC System TG-VLC Submission Slide 6 Taehan Bae et al., Samsung doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 Band plan design for communicating supported channels Source: http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/chap17/F17-03%20Chromaticity%20diagram%20(Gage).jpg
Submissio n Slide 7 Ying Li, Samsung Electronics doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 Notes from CIE diagram Center colors are narrower in width than outer colors. Human eye is more sensitive to center colors pB LED manufacturers make LEDs depending on human color perception and not frequency band => Non-linear widths needed for band plan Submissio n Slide 8
Ying Li, Samsung Electronics doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 Human eye response to wavelength Submissio n Slide 9 Ying Li, Samsung Electronics doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 Proposed Band Plan (based on CIE diagram) Frequency band (nm)
Spectral width (nm) Color Proposed Code 380 450 70 pB 000 450 510 60 B, BG 001
510 560 50 G 010 560 600 40 yG,gY, Y,yO,O 011 600 650 50 rO
100 650 710 60 R 101 710 780 70 R 110 Reserved 111 Red popular
LED for comm. Non-uniform distribution based on CIE diagram Human eye most sensitive to green color and visible LEDs are designed to match human eye sensitivity Provides support for up to 7 independent and parallel channels can consider expansion to more channels Submissio n Slide 10 Ying Li, Samsung Electronics doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 Bandplan issue: Leakage from other LED colors Source: http://www.theledlight.com/technical3.html Submissio n Slide 11 Ying Li, Samsung Electronics
doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 White LED spectrum (Blue + Phosphor) Blue LED (GaInN) Light sensitivity to human eye Yellow Phosphor yttrium aluminum garnet (YAG) leakage if not used at RX Source: Maxim, Application Note 3070 : Standard and White LED Basics and Operation Submissio n Slide 12 Ying Li, Samsung Electronics doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx
July 2009 Need for guard colors Many LEDs (such as white) may not support saturated colors and may transmit in multiple bands Spectrum affected by leakage may be unusable For FDD mode, adjacent bands may be impacted by spectral leakage from own transmitter Significant variations in LED spectral width and peak wavelengths for different manufacturers and costs LED peak wavelength can change with forward current variations. Submissio n Slide 13 Ying Li, Samsung Electronics doc. : IEEE doc.:802.15-15-09-0550-00-0007 IEEE 802.15-xxxxx July 2009 Guard colors
We define guard color channels for each channel used for transmissions. For example, white led (blue + phosphor) Color code : 001 Guard codes : 011, 100 For every channel color, we define a list of guard colors that cannot be used simultaneously for TX or RX when that channel is in use for TX due to leakage. Example: Guard colors (011,100) for 001 can be represented as: 00011000 The criteria used for defining a guard color channel could be based on out-of-band leakage, exceeding a certain value (for example, 10 -20 dB) over the in-channel value that causes a considerable loss in receiver sensitivity in those channels. The guard colors are defined on a per channel basis and could be also be defined as a N-bit number with a 1 in the location where the channel cannot be used. Submissio n Slide 14 Ying Li, Samsung Electronics July 2009 doc.: IEEE 802.15 09-0550-00-0007 Considerations of VLC PHY Modulation Illumination Property Can be mainly used and considered in case of lighting communication using an LED. (e.g. Information Broadcasting, and Visible LAN)
In general, PWM method is used in order to adjust the brightness of LED lighting. But, the method may not be suitable for high speed communication. Also, the lighting function can not be ignored. High Data Rate Single LED device based - Intensity Modulation / Complex Modulation Multiple LED device based - WDM Multiplexing method / Optical MIMO * Source: 2008-11_15-08-0788-01-0vlc-considerations-on-vlc-modulation TG-VLC Submission Slide 15 July 2009 doc.: IEEE 802.15 09-0550-00-0007 Considerations of VLC PHY Modulation Channel Model The VLC may be almost expected to LOS channel
Mobile to Mobile (Short range environment) - relatively little multipath/Interference distortion Infra to Mobile - Interference can be existed. / Downlink beam angle is relatively wider. * Source: 2008-11_15-08-0788-01-0vlc-considerations-on-vlc-modulation TG-VLC Submission Slide 16 July 2009 doc.: IEEE 802.15 09-0550-00-0007 Summary PHY considerations Data rate: ~100Mbps Short range Full Duplex (except for some application) Band Plan supporting 7 independent color channels proposed Can consider more channels
Guard colors proposed for interference mitigation due to leakage Consideration of modulation Illumination High data rate Channel model TG-VLC Submission Slide 17 Taehan Bae et al., Samsung
