doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> January 2016 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 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. Slide 1 Jaesang Cha, Seoul National Univ. of Science & Tech. <author>, <company>

Contents Introduction 6/18/2018<month year> January 2016 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

Introduction (1) Smart Device Light (Flash, etc.) based OWC January 2016 Introduction (1) Smart Device Light (Flash, etc.) based OWC Another Device Camera Smart Device Camera Smart Device (App based Tx ) Low Speed PD

January 2016 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 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.) Cloud Network Connect by Wi-Fi/BT Smart Device Light + RF Camera + RF Link, URL, IP Address, etc - 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

Introduction (4) Authentication using Smart-Device Light and Camera January 2016 Introduction (4) Authentication using Smart-Device Light and Camera LBS using Smart-Device Light(using Offset-VPWM) and Camera LED Light Smart Device (LBS) Gateway (Camera) Smart Device

App. based Smart Device Light Control(1) January 2016 App. based Smart Device Light Control(1) DLT <SW structure of Smart Device > <SW structure of Smart Device + Flash Light Tx App. > Proposed scheme is App. based Device Light system without HW change Just have only to add(install) “Device light transmitter(DLT)” App.

App. based Device Light Control(2) January 2016 App. based Device Light Control(2) App. (Application) Device Light(Flash, etc.) control App. : Light on/off control by calling framework IO Main control block for Device light control Frame Work (Light IO IF) SW Device Light IO interface : Calling Devie Light driver Kernel layer (S/W Driver) Flash Light IO interface : On/Off Control of device Flash device, etc. HW Turn on or off light App. is main control block for Device Light(Flash, etc.) control

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

January 2016 Comparison App. based Flash Light control with HW Modem based Light control(2) HW modem based light control App. based Flash Exact time span Jitter @ falling edge Jitter @ rising edge 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

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 < Mapping Table> Data bits Pulse width 00 P 01 P+V 10 P+2V 11 P+3V < Offset-VPWM scheme>

January 2016 Offset-VPWM (2) Even though rising edge jitter happened, receiver can synchronize rising edge and check pulse width length

January 2016 Offset-VPWM (3) 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) P Jitter @ falling edge 0 0 00  01 v 0 1 Efficient offset value design is needed considering the relation falling jitter and pulse width

The number of simulation data 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 <Simulation Parameters> Item Value modulation Offset-VPWM P 40ms Falling edge jitter 0, 1, 2, 3, 4, 5% of P PWM offset length(v) 10, 20, 30, 40, 50% of P The number of simulation data 1000000 < Offset-VPWM scheme> *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.

BER Performance(2) January 2016 <Pulse offset length 10% of P>

6/18/2018<month year> January 2016 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.