Standby Energy Analysis and Optimization for Smartphones

As smartphones become more and more powerful and complex, many research works have focused on the analysis and optimization of smartphone energy consumption. Most works are focused on the cases when smartphones are actively used. However, one major issue with smartphones is that the standby time has become much shorter compared with traditional feature phones. Many users have to recharge their phones everyday even though they are not using the phones very often. In order to understand what happens with smartphone battery while the phone is not in use, we combine current measurements with user trace analysis to reveal how smartphones consume energy in the standby mode. We have identified several factors that cause energy wastes in the standby mode. Then we propose a series of optimization methods to demonstrate the potential of energy reduction on smartphone standby energy. Results based on user traces show that we can extend the standby time by as much as 87% with the proposed optimizations.