Location problems in renewable sensor networks with wireless energy transfer

The area of wireless sensor networks (WSNs) has recently received a lot of attention. Nevertheless, the major problem is the finite electrical batteries in sensors, which prevents the wide use of WSNs. However, technologies of the wireless energy transfer may be applied to solve energy problems in WSNs with the use of wireless energy chargers. In this study we offer the techniques of finding the points, which are most suitable for a simultaneous omnidirectional wireless charge of a group of sensors. The wireless chargers in question can be both mobile or static. The stated problems are quite similar to the problems of p-center and p-median location in a graph and may be solved by appropriate methods. The approach proposed may significantly decrease a path of a mobile charger when traversing places for recharging sensors. For the WSNs with static wireless chargers these optimal points are useful for the chargers deployment.