Coordinated flocking of UAVs for improved connectivity of mobile ground nodes

Unmanned aerial vehicles (UAV) have been used by the military for surveillance and reconnaissance operations for the past few decades. The recent proliferation of wireless networking technologies enables the equipment of UAVs with wireless transceivers, and that can in turn allow them to communicate with the friendly ground nodes as well as other UAVs. Since rugged ground terrain can result in significant signal attenuation, the ground network can be severely partitioned. However the lower propagation loss between ground and airborne nodes can be effectively utilized to connect the islands of connectivity on the ground to farm a unified ad hoc network. In this paper, we investigate the UAV placement and navigation strategies with the end goal of improving network connectivity. Since the ground nodes can be mobile, a fixed placement strategy is either inadequate or wasteful; hence, we propose to use local flocking rules that aerial living beings like birds and insects follow, to meet our goals. We show by simulation that a flocking based navigation strategy is adaptive to the motion of ground nodes and can indeed maintain high connectivity in a mobile ground network.