1. March 2017
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: CHANNEL MODELS FOR VEHICULAR LIGHT COMMUNICATION APPLICATIONS
Date Submitted: March 2017
Source: Soo-Young Chang (SYCA), Mariappan Vinayagam (SNUST), and Jaesang Cha(SNUST)
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Abstract: Some channel models considered for vehicular LCapplications are defined in this document.
Purpose: To suggest some channel models for vehicular LC applications.
Notice: This document has been prepared to assist the IEEE P 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 P
Submission

2. Channel Models of Vehicular Light Communication Applications
Soo-Young Chang [SYCA]
And
Jaesang Cha [SNUST]

3. CHANNEL MODELS WITH AWGN
AWGN Channel models
Consider X, Y, and Z or R, G, and B.
Add AWGN with fixed value of σ2 to each value

4. CHANNEL MODELS WITH REAL ADJACENT INTERFERENCE
Consider X, Y, and Z or R, G, and B.
Add real interference from sun, incandescent light, fluorescent light, etc. with fixed weight for each interference type to each value
With this model, lower frequency components have more impact than higher frequency components.
But this model reflects more realistic situations.

5. CHANNEL MODELS FOR VEHICULAR APPLICATIONS (1)
Assumptions
AWGN (Additive White Gaussian Noise)
Interference is generated by background noise.
Channel model
where Y(t): received signal current
R: receiver responsivity
X(t): transmitter optical pulse
h(t): impulse response
N(t): AWGN
I(t): interference from background light

6. CHANNEL MODELS FOR VEHICULAR APPLICATIONS (2)
Channel model 1 (cont’d)
Average optical power, Pt,
Optical loss is expressed by the channel DC gain, H(0),
Average received power at the receiver, Pr,

7. CHANNEL MODELS FOR VEHICULAR APPLICATIONS (3)
Background noise
Indoor fluorescent lamp
Strong light noise is caused by a fluorescent lamp around the level of 100/120Hz and 30kHz-500kHz.
When this frequency band is avoided, the band of 1kHz-30kHz or more than1MHz will be used with the sub carrier modulation.
It is not particularly easy for the white LED to modulate at high speed in bands of more than 1MHz, and the frequency division for the sub carrier in each source of light is more difficult.
We must research the methods to assign appropriate sub carrier frequency to each source of light in various ways.
Outdoor sunlight
We may consider the sunlight noise to be a constant light (DC). Single Photo Diode cannot receive the light signal when it is saturated by the sunlight .
This can be happened by the surrounding background light even if the sun doesn‘t enter into FOV (Field Of View) of Single PD directly.
* about-vlc-using-arrayed-pd-image-sensor

8. ISSUES CONSIDERED FOR LINK BUDGET
Link budget considered from Channel models
Needs channel models to be applied for vehicular applications
Free space loss
Losses due to weather: snow, rain, fog, etc.