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Submission

doc. : IEEE 802. 15-14-0XXX-00-007a

Slide 1

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [Synchronization and Flickering Issues of OCC]Date Submitted: [January, 2014]Source: [Yeong Min Jang, Ratan Kumar Mondal, Nam Tuan Le, Shareef Ithekhar, and Trang Nguyen]

[Kookmin University] Address [Kookmin University, Seoul, Korea]Voice:[82-2-910-5068], FAX: [82-2-910-5068], E-Mail:[yjang@kookmin.ac.kr]Re: []

Abstract: [The scope, purpose and reason of the proposed project are described]

Purpose: [Contribution to IEEE 802.15.SG7a OCC]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.

January 2014

Yeong Min Jang, Kookmin University

doc.: IEEE 802.15-14-0041-00-007a

doc.: IEEE 802.15-xxxxx

Submission

doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a

Slide 2 Yeong Min Jang, Kookmin University

January 2014

1s

1/30s

#1 #2 #30#29…..…..

#15

Frame sampling

Optical Camera Communication (OCC)

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Challenges of OCC System

Slide 3 Yeong Min Jang, Kookmin University

Some challenges for implementing OCC System: Reception Technique:

Unstable camera frame rate Need to find a suitable uplink for CamCom system LED source separation for MIMO operation in OCC transmitter

January 2014 doc.: IEEE 802.15-14-0041-00-007a

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Slide 4 Yeong Min Jang, Kookmin University

January 2014

- Effect of exposure value:

Minimum Exposure value available(but could make a bad image quality)

EV Samsung S4 Iphone 5

Exposure 0.0001s 0.0005s

OCC Synchronization

Bad sampling occurs Shutter open

Shutter close

Data of LEDs

Captured Frames

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Slide 5 Yeong Min Jang, Kookmin University

January 2014

- Effect of frame rate variation:

Measured from: Webcam Samsung-SPC A400M

OCC Synchronization

Readout Time may change while processing data.

doc.: IEEE 802.15-14-0041-00-007a

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Slide 6 Yeong Min Jang, Kookmin University

January 2014

OCC Synchronization

Perfect Synchronization Loss Synchronization

#1 #2 #N#N-1

…..

#1 #2 #N#N-1

…..

Frames

Data

- Exposure effect- Frame rate changes during transmission

= Need to be considered in OCC

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doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a

The synchronization hampered due to the unstable frame rate of different kinds of cameras. According to the measurement the time duration between two capturing frame rate are not stable

Slide 7 Yeong Min Jang, Kookmin University

Synchronization of OOK OCC System

< Webcam Colorvis >

<Webcam Samsung SPC-A400M>

January 2014 doc.: IEEE 802.15-14-0041-00-007a

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Submission

doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a

Slide 8 Yeong Min Jang, Kookmin University

January 2014

Synchronization Issues in OCC

Service Scenario:•Synchronized protocol

•Asynchronized protocol

Approach Issues:•Asynchronous scheme for unstable frame rate

•Feedback clock rate for synchronization

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doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a

Slide 9 Yeong Min Jang, Kookmin University

January 2014

FlickeringResponse

0 ~100Hz ~1,000Hz

Eyes cutoffFreq.

Max shutter speedavailable

Frequency

Available range of frequency for modulation of OCC is from 100Hz to 1,000Hz

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doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a

Slide 10 Yeong Min Jang, Kookmin University

January 2014

OCC Flickering Issues

Service Scenario:•Indoor service

•Outdoor service

Modulation scheme:•OOK

•Manchester coding

•Subcarrier Frequency

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doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a

Conclusion

• Synchronization in OCC must consider effect of exposure and frame

rate variation

• Need to proposed a synchronization process which can adapt with the

different frame rate of the camera

• In OCC, frequency range available for modulation is limited by shutter

speed of camera

Slide 11 Yeong Min Jang, Kookmin University

January 2014 doc.: IEEE 802.15-14-0041-00-007a