1. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802. 15-14-0XXX-00-007a Slide 1 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

2. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 2Yeong Min Jang, Kookmin University January 2014 1s 1/30s #1#2#30#29 ….. # 15 Frame sampling Optical Camera Communication (OCC) doc.: IEEE 802.15-14-0041-00-007a

3. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Challenges of OCC System Slide 3Yeong 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

4. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 4Yeong Min Jang, Kookmin University January 2014 -Effect of exposure value: Minimum Exposure value available (but could make a bad image quality) EVSamsung S4Iphone 5 Exposure0.0001s0.0005s OCC Synchronization Bad sampling occurs Shutter open Shutter close Data of LEDs Captured Frames doc.: IEEE 802.15-14-0041-00-007a

5. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 5Yeong 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

6. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 6Yeong 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 doc.: IEEE 802.15-14-0041-00-007a

7. doc.: IEEE 802.15-xxxxx Submission 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. A ccording to the measurement the time duration between two capturing frame rate are not stable Slide 7Yeong Min Jang, Kookmin University Synchronization of OOK OCC System January 2014 doc.: IEEE 802.15-14-0041-00-007a

8. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 8Yeong 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 doc.: IEEE 802.15-14-0041-00-007a

9. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 9Yeong Min Jang, Kookmin University January 2014 Flickering Response 0~100Hz ~1,000Hz Eyes cutoff Freq. Max shutter speed available Frequency Available range of frequency for modulation of OCC is from 100Hz to 1,000Hz doc.: IEEE 802.15-14-0041-00-007a

10. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-15-09-0549-00-0007doc. : : IEEE 802. 15-14-0XXX-00-007a Slide 10Yeong Min Jang, Kookmin University January 2014 OCC Flickering Issues Service Scenario: Indoor service Outdoor service Modulation scheme: OOK Manchester coding Subcarrier Frequency doc.: IEEE 802.15-14-0041-00-007a

11. doc.: IEEE 802.15-xxxxx Submission 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 11Yeong Min Jang, Kookmin University January 2014 doc.: IEEE 802.15-14-0041-00-007a