Use of aerial platforms for energy efficient medium access control in wireless sensor networks

This paper explores the potential of a novel approach to energy efficient medium access control for wireless sensor networks, whereby an aerial platform is employed to remove the distributed coordination and/or relaying burden from the network. A review of state of the art medium access control protocols highlights the limitations of existing techniques. Two alternative strategies are considered which exploit the centralised resource assignment capability of an aerial platform. A medium access control protocol is presented which uses the aerial platform as a centralised coordinator, gathering topology information from the network and using it to compute energy and delay efficient schedules that inherently form the routes. An alternative protocol is described to assign capacity to nodes on a dynamic basis without any form of node addressing. It supports direct transmission to an aerial platform serving as a centralised sink, removing the huge energy burden associated with multi hop relaying. It is shown that direct transmission to an aerial platform provides the most energy efficient solution and rapid transfer of packets over a single hop. Use of a platform as a centralised coordinator provides significant gains with respect to conventional distributed scheduling within the network, and supports the transfer of data to multiple ground based sink nodes.