Power-aware communication for wireless sensor-actuator systems

This paper considers the design of power-aware communication protocols for a sensor transmitting plant state measurements over a wireless Markov fading channel to a receiver/controller. Communication requires power consumption at transmission adapted to channel fading, and at the receiver, which we model as constant at each transmission. We measure performance with a weighted sum of the average power consumption at both ends and an appropriately defined control task error. We derive an optimal self-triggered protocol where after each transmission devices decide when the next one will take place and switch to a zero-power sleep mode in between. We show that sleep durations need to adapt only to the current channel fading and not the plant state. We then derive an improved protocol allowing the sensor upon wake-up to decide whether to transmit or not based on current plant and channel conditions in an event-based fashion. The power/control performance improvements are illustrated in simulations.