Power management in energy harvesting embedded systems with discrete service levels

摘要

Power management has been a critical issue in the design of embedded systems due to the limited power supply. To prolong the lifetime, energy minimization has been studied under performance constraints in the past decade. The emerging embedded systems with the capability to harvest energy from the environment have recently triggered the revision of power management to improve the quality of service dynamically. As the available power/energy of an electronic device changes over time and is limited by many environmental factors, the system has to decide when to change to which service level to provide better quality of service without wasting the harvested energy. In this paper, we explore how to maximize the quality of service, in terms of system rewards, of a periodic application with discrete levels in an energy harvesting system. To decide service levels in a time horizon, this paper presents algorithms to derive optimal solutions if the future harvested energy is known. In addition, we present efficient algorithms to derive near-optimal solutions approximately. Our work is supported by simulation results which are based on long-term measurements of the power generated by real solar cells.