(A) study on thermal characteristics of smartphones

Abstract

Smartphone overheating could affect user experiences and cause thermal pains, but there is a lack of a systematic measurement study. We thus perform extensive thermal measurements to understand the thermal characteristics of smartphones. Using thermal imaging cameras, we measure and analyze the temperatures of a smartphone's surface and its internal components, while running diverse applications such as video chat, 3D gaming, navigation, VR, and deep learning. Our experiments showed that running popular applications, such as video chat, could raise the Nexus 5X's surface temperature to over $50^\circ C$ in only 10 minutes, which could easily cause thermal pain to users. We also perform user studies to examine when the users perceive heat from the smartphones, how they react to it, and how they feel about the thermal issues. Most of our user study participants (83%) reported considerable thermal discomfort while playing a mobile game. Additionally, we present a smartphone surface temperature prediction model, by using only system statistics and sensor values. Our evaluation showed high prediction accuracy with root mean square errors less than $2^\circ C$. We believe our work could have implications on thermal management policies, thermal-aware interactions, and thermal profiling support for developers.