Using Unmanned Aerial Vehicle to Connect Disjoint Segments of Wireless Sensor Network

This paper presents a method for federating disjoint segments of Wireless Sensor Networks (WSNs) using an Unmanned Aerial Vehicle (UAV) for message ferrying. Since network disconnections compromise the system operation, providing an alternative to mitigate disconnections can extend its lifetime. Several other proposals tackle the problem of disconnections by means of redundant deployment or even using mobile nodes as relay stations. Our approach goes beyond previous by connecting network segments localized more than two hops apart using a limited number of mobile nodes. In order to use less mobile nodes (here we are proposing only one), the UAV becomes a data mule, carrying physically packets across the network when moving. Each disjoint segment elects a cluster head which is responsible to coordinate the interaction with the UAV. Simulations realized evince the effectiveness of our system: for moderate traffic and enough data buffers, a very small packet loss was noticed. A considerable latency was observed due to the limited speed of the UAV making our system ideal to delay tolerant applications.