| A key problem in Rechargeable Wireless Sensor Networks (r-WSNs) is determining the maximum amount of data that can be collected by a sink over a given time period. This maximum is constrained by link capacity and critically, by the available energy at each node. In this paper, we consider a novel approach to increase the maximum flow rate by exploting recent advances in Wireless Power Transfer (WPT). Specifically, we deploy a finite number of WPT capable rovers next to bottleneck sensor nodes with the aim to increase the max flow rate of a WSN. We formulate a Mixed Integer Linear Programming (MILP) to determine the routing and the set of sensor nodes that are to be ``upgraded'' in order to achieve the maximum flow rate. We also outline a novel heuristic, called Path, to place rovers in large scale WSNs. Our results show it is able to attain on average 85.9% of the optimal flow rate. |