1. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Offset Variable Pulse Width Modulation for Smart Device Flash Light Date Submitted: 10 January, 2016 Source: Jaesang Cha, Junghoon Lee, Seonhee Lee, Soo-Young Chang and Soonho Jung [SNUST] Address : Seoul National University of Science & Technology [SNUST], Seoul, Korea Voice: +82-2-970-6431, FAX: +82-2-970-6123, E-Mail: chajs@seoultech.ac.kr Re: Response to Call For IEEE802.15.7r1 Proposal on November 2015 Abstract: Offset Variable Pulse Width Modulation for Smart Device Flash Light is proposed. Purpose:Call for Proposal to IEEE 802.15.7r1 Optical Wireless Communication Response Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussio n 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, a mend 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. Slide 1 January 2016

2. Submission Doc: IEEE 802. 15-16-0026-02-007a Slide 2 Contents Introduction App. based Smart Device Light(Flash, etc.) Control Comparison App. based Flash Light control with HW Modem based Light control Offset-VPWM BER Performance Conclusion Jaesang Cha, Seoul National Univ. of Science & Tech January 2016

3. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 3 Introduction (1) Smart Device Light (Flash, etc.) based OWC January 2016 Smart Device (App based Tx ) Smart Device Camera Another Device Camera Low Speed PD

4. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 4 Introduction (2) Low rate OWC (such as LED-ID and OCC) can be sent by Device Light and can be received by low rate PD or Camera. Below picture is an example of Smart Devices. - Left one shows low rate PD communication. - Right one shows Camera communication. January 2016

5. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 5 Introduction (3) Proposed OWC/RF Hybrid mode can access High rate data from cloud by OWC address Pointer(URL, Address etc.) Hybrid Tx : Smart device Light(Flash, etc.) & RF(3G/LTE, WiFi, Bluetooth etc.) Hybrid Rx : Smart device Camera & RF(3G/LTE, WiFi, Bluetooth etc.) January 2016 - Smart Device Light’s data : OWC IP address Pointer (URL, Storage address etc.) - RF data : High rate based access function to Virtual Cloud Big Data Network(Storages) - Virtual Big data exchange(Flexible IoT solution) is available using Hybrid mode Cloud Network Connect by Wi-Fi/BT Smart Device Light + RF Camera + RF Link, URL, IP Address, etc

6. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 6 Introduction (4) Authentication using Smart-Device Light and Camera LBS using Smart-Device Light(using Offset-VPWM) and Camera January 2016 LED Light Smart Device (LBS) Gateway (Camera) Smart Device

7. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 7 January 2016 Proposed scheme is App. based Device Light system without HW change Just have only to add(install) “Device light transmitter(DLT)” App. App. based Smart Device Light Control(1) DLT

8. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 8 January 2016 App. (Application) Frame Work (Light IO IF) Kernel layer (S/W Driver) Flash device, etc. App. based Device Light Control(2) Device Light(Flash, etc.) control App. : Light on/off control by calling framework IO Main control block for Device light control Device Light IO interface : Calling Devie Light driver Flash Light IO interface : On/Off Control of device Turn on or off light SW HW App. is main control block for Device Light(Flash, etc.) control

9. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 9 January 2016 Comparison App. based Flash Light control with HW Modem based Light control(1) HW modem based light control system can turn on/off light at absolutely exact time duration due to HW clock synchronization App. based light control can’t keep turning on/off timing because it is performed by CPU

10. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 10 January 2016 Comparison App. based Flash Light control with HW Modem based Light control(2) App. based Flash control can’t keep exact on/off timing when context switching process, ISR(interrupt service routine), and so on… It can happen both rising and falling edge time HW modem based light control App. based Flash light control Exact time span Jitter @ falling edge Jitter @ rising edge

11. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 11 January 2016 Offset-VPWM (1) In order to overcome Jitter problem, we propose new modulation scheme Offset-VPWM(Variable Pulse Width Modulation) In Offset-VPWM, Data is expressed with offset pulse width For example, 2bits data were mapped into 4 Offset-VPWM symbol as below Data bitsPulse width 00P 01P+V 10P+2V 11P+3V

12. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 12 January 2016 Offset-VPWM (2) Symbol length : P, P+V, P+2V, P+3V 0 0 1 1 0 1 P v v v v v v Symbol length Symbol length Data bits Symbol P P+V P+2V P+3V

13. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 13 January 2016 Offset-VPWM (3) Symbol arrays example 0 0 01 10 11 Data bits Symbol arrays P v v v v v v P P P P P P Symbol transition duration = P 0 01 10 11 In order to transmit next symbol after sending one symbol, symbol transition duration is needed This is flash on/off switch timing by App.

14. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 14 January 2016 Offset-VPWM (4) Symbol arrays example considering rising & falling edge jitter 0 01 10 11 0 01 10 11 Symbol length offset Falling edge jitter Rising edge jitter Symbol length When no jitter happened When rising/falling jitter happened Smart device’s light signal contains variable symbol length offset Therefore it is called Offset-Variable Pulse Width Modulation

15. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 15 January 2016 Offset-VPWM (5) Even though rising edge jitter happened, receiver can synchronize rising edge and check pulse width length Detection scheme on Rx

16. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 16 January 2016 Offset-VPWM (6) If falling edge jitter happened, it can affect BER performance For example, When sending ’00’, If Tx signals falling edge happened with short pulse width(v) then Rx’s decision making error is occurred (00  01) 0 0 1 P v Jitter @ falling edge Efficient offset value design is needed considering the relation falling jitter and pulse width 00  01

17. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 17 January 2016 BER Performance(1) P is 40ms * Falling edge is varied from 0%~5% of P Offset length(v) is varied from 10~50% of P ItemValue modulationOffset-VPWM P40ms Falling edge jitter0, 1, 2, 3, 4, 5% of P PWM offset length(v)10, 20, 30, 40, 50% of P The number of simulation data1000000 * P value 40ms is calculated via (1second) / (the number of flash blinking) The number of blinking is the capacity how often mobile device can turn flash on and off means that the frequency which was tested using Nexus5S device.

18. Submission Doc: IEEE 802. 15-16-0026-02-007a Jaesang Cha, Seoul National Univ. of Science & Tech. Slide 18 January 2016 BER Performance(2)

19. Submission Doc: IEEE 802. 15-16-0026-02-007a Slide 19 Conclusions Offset Variable Pulse Width Modulation for Smart Device Light(Flash, etc.) are proposed Proposed scheme is App. based Device Light system without HW change Just have only to add(install) “Device light transmitter(DLT)” App. Offset-VPWM can be applied on LED-ID and OCC Application scenarios like OWC/RF Hybrid method, Authentication, LBS were introduced Smart Device based/connected Multiple Device Lights also can be applied Jaesang Cha, Seoul National Univ. of Science&Tech. January 2016