Wenmao Zhou

Unmanned aerial vehicles (UAVs) equipped with communication devices are easy to deploy and can serve as temporary mobile communication stations, covering dynamic ground users and establishing communication links. The proper planning of UAV paths can improve user coverage while maintaining communication quality. The traditional particle swarm optimization (PSO) algorithm exhibits strong global search capabilities; however, it suffers from challenges such as uneven search coverage owing to the random distribution of the initial particle positions. Additionally, improper parameter selection often leads to premature convergence to local optima. This study proposes a method for multi-UAV coverage of dynamic users by combining Tent chaotic mapping with PSO (Tent–PSO). By using Tent chaotic mapping to adjust a UAV’s speed and position, the method ensures that particles are evenly distributed in the search space. Simulation results demonstrate that Tent–PSO improves the coverage of the global optimal solution by 10% and increases throughput by at least 37%, confirming its effectiveness in covering dynamic user scenarios.

A novel adaptive weighted geometric‐shaped (GS) 61 quadrature amplitude modulation (QAM) constellation is proposed in order to mitigate the nonlinear damage and increase the transmission distance. By introducing an adaptive weighting factor related to Kerr effect and fiber transmission distance in concentric regular hexagon constellation, the overlapping problem of the outer constellation points induced by nonlinear damage was reduced. The simulation results show that the proposed GS‐61QAM outperformed uniform 64QAM and has more obvious advantages in long‐haul optical transmission system. For a 120‐Gb/s coherent optical communication system, compared with uniform 64QAM, the proposed algorithm can obtain about 4.1 dB optical signal‐to‐noise (OSNR) gain at the BER of 10⁻². Moreover, in order to further improve the system tolerance of nonlinearity, a scheme of adaptive weighted GS‐61QAM in coherent optical communication system utilizing K‐Means algorithm is proposed, the proposed scheme outperforms the traditional uniform 64QAM communication system by 5 dB in OSNR at the BER of 10⁻².