1. Mobile Middleware for Energy-Awareness Wei Li weli@cc.hut.fi

2. Contents:  Definition and usage  Needs for Energy-Awareness Mobile Middleware  A Solution  Summary

3. 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

4. A typical usage scenario Put the network interface into sleep mode Reduce backlight luminance Lower the video transcoding rate Suggest 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 tunnel 2. When the battery status drops from high to medium 3. When the battery status drops from medium to low

5. Contents:  Definition and usage  Needs for Energy-Awareness Mobile Middleware  A Solution  Summary

6. Why we need such a middleware? 1. More and more multimedia usage.

7. 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 Hz Memory: 16 MB 576 MB Camera: 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?

8. Why 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

9. Why we need such a middleware? charge our nuclear phone once and use it for the entire life Maybe someday…

10. Why we need such a middleware? Let’s get back down to earth Before new technology in energy area, the energy-awareness middleware is indeed needed

11. Contents:  Definition and usage  Needs for Energy-Awareness Mobile Middleware  A Solution  Summary

12. The adaptations: Local: Processor voltage CPU frequency Backlight luminance Network interface settings Global: Transfer some computation from the devices to remote entities Negotiated transmission

13. Architecture

14. Resource Manager Target: separate the low level resources Functions: 1.Process the information requests 2.Control the hardware device

15. 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

16. 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

17. Policy Manager Target: Make different power policies Input: application classification, network conditions, platform settings… Output: adaptive operations

18. 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

19. 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

20. Work flow Step 1 Step 2 Step 3 Step 4 Step 5 Another policy request and execution

21. 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%

22. Contents:  Definition and usage  Needs for Energy-Awareness Mobile Middleware  A Solution  Summary

23. 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

24. Thank you for your attention!