Energy efficient operating mode assignment for real-time tasks in wireless embedded systems

Minimizing energy consumption is a key issue in designing real-time applications on wireless embedded systems. While a lot of work has been done to manage energy consumption on single processor real-time system, few work addresses network-wide energy consumption management for real-time tasks. Moreover, existing work on network-wide energy consumption assumes that the underlying network is always connected, which is not consistent with the practice in which wireless nodes often turn off their network interfaces in a sleep schedule to reduce energy consumption. In this paper, we propose solutions to minimize network-wide energy consumption for real-time tasks with precedence constraints executing on wireless embedded systems. Our solutions take the radio sleep scheduling of wireless nodes into account when adjusting the execution modes of processors. We also propose a runtime dynamic energy management scheme to further reduce energy consumption while guaranteeing the timing constraint. The experiments show that our approach significantly reduces total energy consumption compared with the previous work.