Abstract
In recent years, the products in embedded systems have been growing constantly. Among these development, consumer electronics is the prevalence of electronic equipment intended to be used by people in our daily lives. We can usually find some categories of applications in entertainment, intercommunications, medical appliances, and industrial productivity. For example, mobile phone, PDA, MP3 player, laptop, etc. These systems are ordinarily portable for ideal battery-based products and power management in portable applications is a crucial factor in customer satisfaction and market acceptance. In this scenario, one relevant topic is to increase battery life. In addition, real-time (response time) is an important issue. Some services must be delivered within timing constraints strictly, especially such as mobile phone and wireless communication. For a real-time system, there are two common ways to reduce the power consumption, that is, the processor shutdown and processor slowdown. The dynamic Voltage Scaling (DVS) approach and the Dynamic Frequency Scaling (DFS) approach make use of the slowdown mode, in which the minimization of the energy consumption performance is achieved through the decreasing of the voltage scaling or the CPU frequency. But this strategy is only suitable for processors supporting multiple-supply-voltage. Thus, it will not only raise execution time of the whole system, but also increase power consumption of peripheral devices. To reduce more electricity consumption, one effective approach is to shutdown the device when the overall system is in an idle period larger than the threshold time. This implies that if the timing requirements are met, the shutdown approach is adequate for reducing overall energy consumption. If we shutdown the system more times, the power saved will be increased. In this paper, we propose Enhanced Procrastination Algorithm (EPA) scheme. By applying the EPA and the EDF algorithms, more power can be saved.