2011 ISLPED: Design contest
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2011 ISLPED: Design contest






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2011 ISLPED: Design contest Presentation Transcript

  • 1. A Cloud-Based Energy-Saving Service for Mobile Streaming ApplicationsCheng-Kang Hsieh, Chun-Han Lin, Pi-Cheng Hsiu Research Center for Information Technology Innovation Academia Sinica, Taiwan International Symposium on Low Power Electronics and Design
  • 2. Outline• Introduction• A Dynamic Backlight Scaling Service• Real-World Case Studies• Conclusion 2
  • 3. Motivation• Mobile applications and services are having a profound effect on peoples lifestyles.• The energy consumption of mobile devices is a major challenge in sustaining the applications and services. 3
  • 4. Cloud-based Energy-Saving Services• The concept would be realized as a value-added service offered by ISPs, like AT&T.• AT&T helps mobile devices to save energy when they access Internet applications.• The services must be easy to use & transparent to the users. 4
  • 5. A Dynamic Backlight Scaling Service• The screen backlight consumes most of the energy for mobile streaming applications.• Dynamic backlight scaling is deemed a promising technical solution.• When to dim the backlight to which level? Our ISPLED’11 paper has the answer! LCD CPU, Screen, 17.21% 17.98% WIFI, 4.32% Backlight, 60.49% Power Consumption when Dynamic Backlight Scaling browsing YouTube on iPad 5
  • 6. System Architecture Video Stream Streaming Server Backlight File Backlight ServerMobile Device 6
  • 7. The Cloud Side Download the requested video from YouTube• Responsible for generating backlight files • Analyze the video to decide the critical backlightPhase 1 levels (i.e., the dimmest backlight level with respect to the tolerable video distortion) Critical backlight levels of the video • Determine an optimal backlight assignment for thePhase 2 video based on the device’s power model and capability Backlight File 7
  • 8. The Device Side• Measure power models• Develop mobile application programs Power Monitors iPad’s display subsystem 8
  • 9. System Deployment• The dynamic backlight scaling service has been deployed on Chunghwa Telecom’s hicloud.• The mobile application program for Android is going to be released in the Android Market for free. 9
  • 10. Approach Validation• Process Time & Transmission Delay Video Download Phase I Phase IICloud Side 124 seconds 1020 seconds Backlight File 2.1 seconds Transmission Delay 335 milliseconds Device Side• Video Perceptual Quality (Demo) 10
  • 11. Performance EvaluationCase Studies Experimental Results 11
  • 12. Conclusion• We raise the concept of cloud-based energy-saving services. – The dynamic backlight scaling service has been deployed on CHT hicloud as a prototype service. – Two mobile application programs were developed for Google’s Android and Apple’s iOS. – With the service applied, HTC Desire and Apple iPad achieved energy savings of 11-20% and 31-41% when browsing videos on YouTube.• We will release the mobile application programs to seek the feedback on the performance and identify the issues that require further investigation. 12
  • 13. We are the Research Center for IT Innovation 13