A real-time feedback scheduler for environmental energy harvesting

The use of environmental energy such as solar energy has recently emerged as an option to increase the operating time of embedded systems (e.g. wireless sensors). It consists in converting ambient energy into electricity to power and lengthen battery life. Dynamic voltage scaling (DVS) is one of the most effective techniques for reducing energy consumption in embedded and real-time systems. However, traditional DVS algorithms have inherent limitations on their capability in energy saving since they rarely take into account the actual application requirements and often exploit fixed timing constraints of the real-time tasks. Some authors used feedback scheduling techniques in order to minimize the consumed energy by observing the actual usage of resources in the system. This paper combines the use of DVS and energy harvesting with the capabilities of a feedback scheduler. Our goal is to minimize the consumed energy, as well as to take the charging model into account.