User-centric Joint Power and Thermal Management for Smartphones

Excessive power consumption and high temperatures are some of the key factors limiting battery charge life and performance of current mobile devices or smartphones. Existing power management solutions do not account for user-experience, which can impact user satisfaction. In this paper we propose a joint power and thermal management solution, which takes a proactive approach in reducing energy consumption while providing expected user-experience. The proposed technique modulates the operating conditions based on users application preferences and exploits the "change blindness" effect to reduce display power consumption. Another important aspect of our implementation is that it does not require any restructuring of the underlying operating system. A novel thermal model of the entire smartphone was built with the purpose of monitoring and controlling the operating conditions to keep the device temperatures within safe operating ranges. Our ready-to-use management technique has been implemented on Google Nexus 5 and has been demonstrated to achieve a 46% application-specific savings on power consumption and up to 35% savings in power consumption at the device level. The mean temperature estimation error is 1.17 degrees C.