Mobile Middleware for Energy-Awareness

Mobile Middleware for Energy-Awareness

Wei [email protected]

Contents:

Definition and usageNeeds for Energy-Awareness Mobile

MiddlewareA SolutionSummary

Definition

• The framework with which the mobile devices make power adaptations

• Considerations: current battery status, local CPU demand, and network environment.

• Hide the heterogeneity of low level platforms, and thus enable the higher layers of the system to build scalable solutions.

Target: prolong battery use time in the meantime provide acceptable QoS

A typical usage scenario

Put the network interface into sleep mode

Reduce backlight luminanceLower the video transcoding rateSuggest user to stop watching video when the battery is even lower

Reduce the message sending rate. Filter the messages according to the priority

1. When the train is going through a tunnel2. When the battery status drops from high to medium3. When the battery status drops from medium to low

Contents:



Why we need such a middleware?

1. More and more multimedia usage.

2. Battery technology evolves really slowly

Comparison between two smart phones in ten years:Nokia 9210 Communicator (2000) VS. HTC Desire (2010)

Hardware:Processor : 52 MHz 1G HzMemory: 16 MB 576 MBCamera: NA 5 megapixel

Network: EGSM HSCSD 43.2 Kbit/s WCDMA/HSPA 14 Mbit/s

Software:Don’t even want to start it

…..

Battery: Li-Ion 1300 mAh Li-Ion 1500 mAh

Why do we need such a middleware?


3. Battery is the most restricting factor for Mobile phones

If we have more powerful battery?

Bigger screen, watch a couple of movies on the plane, charge once and use one month


charge our nuclear phone once and use it for the entire life

Maybe someday…


Let’s get back down to earth

Before new technology in energy area, the energy-awareness middleware is indeed needed

Contents:



The adaptations:

Local:• Processor voltage• CPU frequency• Backlight luminance• Network interface settings

Global:• Transfer some computation from the devices to remote

entities• Negotiated transmission

Architecture

Resource Manager

Target: separate the low level resources

Functions:

1. Process the information requests2. Control the hardware device

Application Classifer

Target: Classify applications into different classes

Resource consumption patterns:

CPU processing load {LOW, HIGH} Memory access mode {STABLE,

BURSTY} Network transmission load {LOW,

HIGH}

Currently three classes:

audio/video decoder/encoder, intensive network transmission, extensive network transmission

Power Estimator

Target:Estimate the power consumption for the application

Component-level power modeling:Unconcerned about application details.

Application-level modeling:Power estimation for each application

Policy Manager

Target:Make different power policies

Input: application classification, network conditions, platform settings…

Output: adaptive operations

Processing Engine

Target: Responsible for scheduling power adaptations automatically

The procedure:

1. Subscribe to the resource manager for events

2. Request for application classification, power estimation or policy

3. Execute policy

Messaging

Target:

1. Communicate with other middleware and OS components

2. Communicate with remote entities

Inter-process communication (IPC) such as D-Bus is used for the first target

HTTP is used for the second target

Work flow

Step 1

Step 2

Step 3

Step 4

Step 5

Another policy request and execution

Evaluation environment and result:

• Device: Nokia N810 Internet tablet• Download and playback content: a YouTube video

clip with duration of 257 seconds. File size 9472KB.• Network environment: 802.11g WLan

• Result: the energy consumption is reduced by 8%

Contents:



1. Save the energy consumption while provide an acceptable quality of service for mobile devices.

2. Independent on operation system and hardware

3. Possible to extend to a distributed middleware with a proxy

Thank you for your attention!

Documents

Mobile Middleware for Energy-Awareness