Efficient sensor subset selection and link failure response for linear MMSE signal estimation in wireless sensor networks

We consider two aspects of linear MMSE signal estimation in wireless sensor networks, i.e. sensor subset selection and link failure response. Both aspects are of great importance in low-delay signal estimation with high sampling frequency, where the estimator must be quickly updated in case of a link failure, and where sensor subset selection allows for a significant energy saving. Both problems are related since they require knowledge of the new optimal estimator when sensors are removed or added. We derive formulas to efficiently compute the optimal fall-back estimator in case of a link failure. Furthermore, we derive formulas to efficiently monitor the utility of each sensor signal that is currently used in the estimation, and the utility of extra sensor signals that are not yet used. Simulation results demonstrate that a significant amount of energy can be saved at the cost of a slight decrease in estimation performance.