Optimal Power Allocation for Wireless Sensor Networks with Outage Constraint

This letter considers the power allocation problem for a wireless sensor network, where N distributed sensors transmit delay-limited high rate traffic to a fusion center (FC) via orthogonal channels. The system-level outage event is defined as that the FC can decode none of the messages from the N sensors. We formulate the outage probability minimization problem with a sum power constraint, and show that this problem, albeit being non-convex, possesses an interesting "concave-convex" property in the reformulated form. By exploiting this property, the problem is shown to be solvable optimally via a one-dimension search. Its counterpart problem, i.e., minimizing the sum power consumption with a targeted outage probability, is also solved. Finally, numerical results show that the proposed power allocation can significantly improve the system performance compared to the conventional uniform power allocation.