UAV-Assisted Adaptive Relay Nodes Placement for Network Connectivity Recovery in WSNs

Connectivity is a fundamental requirement for Wireless Sensor Networks (WSNs). Failures in multiple nodes can disrupt network connectivity, leading to the formation of disjointed subnetworks. To restore network connectivity, a UAV-assisted Adaptive Relay nodes Placement algorithm (UARP). is proposed in this paper. To concentrate relay nodes placement and reduce the travel distance of UAVs, a concept of UAV Areas is introduced to identify the areas between interrupted network partitions. Based on the number of network partitions within UAV Areas, two different strategies are employed to place relay nodes and reconnect the partitions for the scenarios with more and fewer partitions, respectively. With the proposed algorithm, relay nodes are strategically placed within UAV Areas, which can reduce the required number of relay nodes and shorten the UAV travel distance. Simulation results indicate that the UARP algorithm reduces relay usage by 10% to 20% and decreases UAV travel distance by 5% to 10% compared to other algorithms. The algorithm also demonstrates satisfactory performance in terms of packet delivery rate, convergence time, and transmission delay.