A selective DVS technique based on battery residual

Conventional research on DVS assumes that the battery, which is the power source of most mobile devices, provides constant power; the battery, however, has unique discharge characteristics due to its chemical properties. Based on the residual characteristics of the battery, this paper presents a practical approach towards a battery-aware DVS mechanism that can easily be applied to conventional operating systems. The proposed policy monitors the battery residual in runtime, classifies the current battery state as one of three—the recovery effect region, the rate capacity region and the alarm region—then applies a suitable DVS algorithm according to each region, which takes advantage of the underlying battery characteristics. Experiments on commercial PDAs (iPAQ5550 and Zaurus SL-860 PDA) running MPEG applications showed that our policy significantly extends the battery lifetime, compared to the conventional DVS method, with only a marginal QoS degradation.