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Wei Li weli@cc.hut.fi. Mobile Middleware for Energy-Awareness. Contents: Definition and usage Needs for Energy-Awareness Mobile Middleware A Solution Summary. Definition The framework with which the mobile devices make power adaptations
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Wei Li weli@cc.hut.fi Mobile Middleware for Energy-Awareness
Contents: Definition and usage Needs for Energy-Awareness Mobile Middleware A Solution Summary
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 1. When the train is going through a tunnel 3. When the battery status drops from medium to low 2. When the battery status drops from high to medium 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
Contents: Definition and usage Needs for Energy-Awareness Mobile Middleware A Solution Summary
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) Why do we need such a middleware? 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 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
Why we need such a middleware? charge our nuclear phone once and use it for the entire life Maybe someday…
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
Contents: Definition and usage Needs for Energy-Awareness Mobile Middleware A Solution Summary
The adaptations: Local: Processor voltage CPU frequency Backlight luminance Network interface settings Global: Transfer some computation from the devices to remote entities Negotiated transmission
Resource Manager • Target: • separate the low level resources • Functions: • Process the information requests • Control the hardware device
Application Classifer • Target: • Classify applications intodifferentclasses • 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: • Subscribe to the resource manager for events • Request for application classification, power estimation or policy • Execute policy
Messaging • Target: • Communicate with other middleware and OS components • 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 Another policy request and execution Step 4 Step 5
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: • Definition and usage • Needs for Energy-Awareness Mobile Middleware • A Solution • Summary
Save the energy consumption while provide an acceptable quality of service for mobile devices. • Independent on operation system and hardware • Possible to extend to a distributed middleware with a proxy