Robust Threshold based Sensor Activation Policies under Spatial Correlation

We consider a system of rechargeable sensor nodes deployed redundantly in the region of interest. Active sensor nodes are subject to a discharge process which depends on the occurrence of events in the system. All sensor nodes experience a continuous recharge of their battery energies, however at a considerably lower rate than of discharge. The decision problem is to find the optimal activation policy for the sensor nodes which would maximize the aggregate system utility. We model our rechargeable sensor system as a system of finite-buffer queues and show the existence of a simple threshold activation policy that achieves near optimal performance. Our results hold both in presence as well as absence of correlation in the discharge and/or recharge processes, thereby showing the robustness of such policies with respect to the degree of correlation in the system.