Energy-efficient voltage scheduling of peripheral components on wireless sensor nodes

Much effort has been put into optimizing the energy-efficiency of wireless sensor nodes, but existing work exclusively focuses on the transceiver and the processing unit. Nevertheless, the peripheral energy consumption may dominate that of the entire node. We introduce the concept of a dynamically scalable peripheral voltage supply: Even for peripheral devices, a lower voltage level leads to a lower energy consumption. Each peripheral requires a different minimum operating voltage, but switching the voltage level consumes energy as well. We combine theory and practice to present an algorithm weighing off the benefits of a downscaled voltage level against the switching overhead, i. e., for calculating an optimal peripheral voltage schedule. Our approach is capable of self-parameterization and has been implemented and tested on a prototype, saving up to 47% of peripheral energy as compared to existing solutions.