Optimum Power Allocation in Sensor Networks for Passive Radar Applications

In the present work, we investigate the power allocation problem in distributed sensor networks that are used for passive radar applications. The signal emitted by a target is observed by the sensor nodes independently. Since these local observations are noisy and are thus unreliable, they are fused together as a single reliable observation at a remotely located fusion center in order to increase the overall system performance. The fusion center uses the best linear unbiased estimator in order to estimate the present target signal accurately. By using the proposed system model, fusion rule and objective function we are able to optimize the power allocation analytically and can hence present a closed-form solution to the power allocation problem. Since the power allocation problem can be subject to different power constraints, three different cases of power constraints are discussed and compared with each other. Furthermore, we demonstrate that all considered constraints lead to signomial optimization problems which are in general quite hard to solve. The main applications of the proposed results are issues concerning the sensor selection and energy efficiency in passive sensor networks.