Minimizing Energy Expenditure

in Smart Devicesin Smart Devices

Soumya Kanti DATTAResearch Engineer

EURECOMFrance

Projet : « Smart 4G Tablet»

LPCIM : Laboratoire de Physique des

Interfaces et des Couches Minces

Contents

• Introduction

• Energy expenditure in smart devices

• Power consumption estimation

• Power optimized application development• Power optimized application development

• User guidelines for battery saving

• Future directions

12/03/2013 3ICT 2013, Tamil Nadu, India

Introduction to the problem

• Desktop-like features consume high power

• Battery capacity is not increasing at the same pace

Smart devices becoming ubiquitous increasing at the same paceubiquitous

• Limited battery life

• Frequent chargingResult

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Roadmap to the solution

• Energy dissipated at hardware and Android applications

• Power consumption estimation analyzing usage pattern

Understanding energy

expenditure

• Power optimized application development

• User guideline to increase battery life

Solutions

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Contents

• Introduction

• Energy expenditure in smart devices

• Power consumption estimation

• Power optimized application development• Power optimized application development

• User guidelines for battery saving

• Future directions

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Power consumption by hardwareD

isp

lay h

ard

wa

re • High brightness

• High screen N

etw

ork

In

terf

ace • Prolong

usage of Wi-Fi, 3G

CP

U • High operating frequency

Dis

pla

y h

ard

wa

re

• High screen time out

• High device interaction time

Ne

two

rk I

nte

rfa

ceWi-Fi, 3G

• Bulk data transfer apps like YouTube

frequency

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Power consumption by Android apps

Frequent waking up in background

Bulk data transfer

Static dissipation

In-app advertisements

Auto-syncIneffective

using of sensors

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Contents

• Introduction

• Energy expenditure in smart devices

• Power consumption estimation

• Power optimized application development• Power optimized application development

• User guidelines for battery saving

• Future directions

12/03/2013 9ICT 2013, Tamil Nadu, India

Power consumption estimation

• Learn usage pattern

• Developed and deployed “Power Monitor”

– Periodically collects data and stores locally.

– Analysis of the data at remote server.

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– Analysis of the data at remote server.

Architecture of Power Monitor

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Real life usage pattern

• Device: Samsung Galaxy S2

• Android version: 2.3.4

• Frequently used applications

– Facebook– Facebook

– Gmail

– Gtalk

– WhatsApp

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Usage pattern contd.

Wireless network usage

Display usage

Interaction = 127min/day & Brightness = 35 Power = 150mAh

GPS usage

Active for 30min = 70mAh Switched off for rest of the time

Wireless network usage

3G active for 105min = 394mAh 3G idle for 1335min = 67mAh

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Contents

• Introduction

• Energy expenditure in smart devices

• Power consumption estimation

• Power optimized application development• Power optimized application development

• User guidelines for battery saving

• Future directions

12/03/2013 14ICT 2013, Tamil Nadu, India

Power optimized app development

• Detect network i.e. EDGE, 3G, Wi-Fi

• Prefetch data & batch upload

• In-exact timer for services

Network operations

• Use network based location• Use network based location

• GPS should be used when high accuracy is needed

• Don’t combine bothLocation

• Tone down brightness from app activities

• Use dark colors for design

• Avoid using live wallpaperDisplay

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Power optimized app development

• Monitor battery level to avoid intense computation at low battery

• Avoid bulk data transfer/auto-sync on low battery

Battery level

• Distribute intense tasks in coding• Distribute intense tasks in coding

• Avoid floating point mathematics

• Careful use of wake locksCPU

• Services should be short-lived

• Use Alarm Manager

• Limit the amount of data transfer (from ICS)Services

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Contents

• Introduction

• Energy expenditure in smart devices

• Power consumption estimation

• Power optimized application development• Power optimized application development

• User guidelines for battery saving

• Future directions

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User guidelines

Reduce Brightness

Turn off Wi-Fi, 3G when not

used

Use battery saving apps

used

Turn off auto-sync

Limited use GPS & other

sensors

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Contents

• Introduction

• Energy expenditure in smart devices

• Power consumption estimation

• Power optimized application development• Power optimized application development

• User guidelines for battery saving

• Future directions

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Future directions

Optimize energy dissipation

Power saving Next generation

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Power saving profiles

generation based on usage pattern

Next generation Android app development

strategies

Conclusions

• Overview of power consumption

• Energy expenditure estimation from usage

pattern

• Roadmap to develop efficient Android apps• Roadmap to develop efficient Android apps

• User guidelines

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Thank youThank you

18/06/2012 ETSIoT 2012, Seoul 22