基於多重事件驅動的行動裝置省電方法

A Power-Saving Approach Based on Multiple Event-Driven for Mobile Devices

吳岱融(Dai-Rong Wu)

指導教授 ： 陳國益

國立虎尾科技大學/電機資訊學院/資訊工程系碩士班/碩士(2016年)

摘要

隨著智慧型行動裝置的發展與廣泛使用，手機效能不斷地提升，但有限的電池容量一直是行動裝置續航力的瓶頸，因此，提高行動裝置的續航力與節能省電的技術日益受到重視。在過去許多的相關的研究裡，有學者提出犧牲效能來提高續航力的研究，但使用者並不樂見影響到使用者體驗的情況。另外，也有其他的研究學者提出不影響使用者體驗的前提下達到省電的效果，然而在這些研究裡都具有應用層面上泛用性不足的缺點，例如需要依賴特定行動裝置或是只能在特定的應用上才能達到省電效益，為了解決以上問題，在本研究中，我們提出基於多重事件驅動的行動裝置省電方法，藉此提高省電的效益。
在操作行動裝置時的畫面流暢度是非常重要的使用者體驗因素之一，本研究透過個案探討發現，在大部分的應用程式底下，若沒有觸控輸入時畫面刷新率會維持在較低的輸出，反之當有觸控輸入時畫面會不斷的更新，畫面刷新率會逐漸提升至輸出上限。除此之外，我們發現可以透過應用處理器至螢幕的傳輸介面(DSI，Display Serial Interface)的傳輸頻率可以控制垂直同步訊號進而控制畫面刷新率的上限，在預設的情況下為了隨時提供最大的畫面刷新率，DSI傳輸頻率始終維持在固定的值，但當行動裝置處於無須高畫面刷新率時，DSI的傳輸頻率應降低以避免冗餘的輸出所造成的額外電力消耗，因此，本研究以觸控輸入事件以及網路流量事件來動態調整DSI傳輸頻率，藉此來達到省電效益。
本研究中提出一個省電機制，其目的在於不破壞使用者體驗的情況下達到省電效益，並且在不同類型的應用程式上測試省電效果，其中包含瀏覽器、社交、即時通訊 (LINE、Facebook Messenger)、影片串流(YouTube)、3D遊戲、雜誌閱覽、娛樂等類型的應用程式中測試本研究提出的省電機制，根據本研究所提出的方法實驗結果得到平均可以節省21.89mA的電流消耗，節省比例約5%。

關鍵字

節能省電 ； MIPI Display Serial Interface ； VSYNC ； Android

並列摘要

With the wide use of smart mobile devices, the battery capacity could be the major reason to limit the use of available time for smart devices. There are many researches focused on the methodologies to improve power endurance with power-saving technologies of mobile device. In the past, a volume of researches has been done on various power-saving approach by reduction the performance of mobile devices. However, the user experiences could be the most important. In the other hand, some researches have been performed on the power-saving and avoided influencing user experience. However, these research have same issue which is not designed for the common use e.g., device dependence, specific applications. Therefore, we improved the issue of wide use by research the hardware interface standard in this work.
The screen fluency could be the major reason to reduce the user experience. Based on the analysis we found the frame rate is lower when user are not touching the screen. On the other hand, the frame rate is max when user are touching the screen. In addition, the Display Serial Interface (DSI) which defines a serial bus and a standard of communication protocol between the application processor and a display module. The clock frequency of DSI can control VSYNC (Vertical sync) signal and then limit the maximum of frame rate, the DSI clock frequency is fixed in default setting to support the maximum of frame rate. Based on our analysis, we can adjust the DSI clock frequency flexibly to avoid redundant power consumption.
In this work, we proposed an multiple event-driven approach called DMP that adjust the DSI clock to limit maximum of frame rate based on motion events and network traffic events to reduce power consumption of mobile devices, and we test various types of applications, such as a browser, instant message (LINE, Facebook Messenger), video stream (YouTube), 3D game and magazine applications. In the result of experiment it reduce the consumption of average current 21.89mA and average power-saving ratio 5% by this work proposed approach.

並列關鍵字

power-saving ； MIPI Display Serial Interface ； VSYNC ； Android

參考文獻

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