UAV Swarm for Connectivity Enhancement of Multiple Isolated Sensor Networks for Internet of Things Application

The Internet of Things (IoT) can be supported by multiple isolated sensor networks (MISN) when the connectivity of IoT is constrained by obstacles. Mobile nodes have been used as relays to connect partitioned networks. However, mobile nodes have the problem of not being able to move or moving slowly when encountering obstacles. In order to tackle this issue, three types of Unmanned Aerial Vehicle (UAV) swarm modes are proposed, and UAV swarm assisted connectivity enhancement algorithms (UsCE) are designed. A UAV swarm with high degree of freedom and flexibility provides a new way in IoT for solving the above connectivity problem. Our target is to find an optimal solution that minimizes the number of UAVs in the swarm and maximizes the connection time of MISN. We divide the working modes of a UAV swarm into hovering and flying. Firstly, the ground sink nodes are classified by a MISN's sink node classification algorithm to generate hovering points for the UAV swarm. Secondly, the results are optimized and adjusted by a minimum UAV swarm hovering connection algorithm to obtain an optimal solution under the hovering mode. Finally, we achieve an optimal connectivity when the UAV swarm works in flying mode through the UAV swarm flight connectivity algorithm and compare it with two previously proposed algorithms. Simulation results show that the complexity of the algorithms is low, the connection time of MISN increases significantly, and the number of UAVs is small. An optimal UAV swarm assisted connectivity enhancement scheme for MISN of different scales is derived.