Optimal dynamic sleep time control in Wireless Sensor Networks

We present a dynamic optimization approach to save energy in Wireless Sensor Networks (WSN) at the link level. One of the main sources of energy waste in a WSN is idle listening, i.e., nodes consuming energy to sample an idle channel. Our approach utilizes known traffic statistics and optimally controls the sleep interval between consecutive wake-ups of the receiver so that the expected total energy spent during each transmission is minimized. We derive necessary conditions for optimality that can be numerically solved but may fail to provide the optimal solution. Thus, we also propose an alternative efficient algorithm providing an explicit discretized solution. Simulation results are included to compare fixed sleep times to our dynamic control policy.