## 5 Conclusions  
Handover technology is necessary to guarantee seamless data service for mobile nodes such as AUVs in B-UWANs. To effectively design handover protocols for B-UWANs, it is important to address the unique challenges of underwater communication, including considerable propagation delays, constrained bandwidth, and susceptibility to various interferences that cause frequent disruptions, along with the varying positions of the BSs. BSs are typically buoyant, floating on the water surface; thus, their positions can vary according to several factors, including currents, waves, winds, and the method of mooring. This BS motion results in variability in the distance between an AUV and a BS, which, in turn, leads to fluctuations in the received signal strength and network connectivity. We cannot precisely estimate the changes in location caused by BS motion with respect to sea conditions. Therefore, we assume that the BS is stationary when determining the AUV-BS distance. However, the actual AUV-BS distance can differ from the estimated distance due to the change in position due to the BS motion, causing errors in handover decision. Consequently, this study analyzed the impact of BS motion on handovers using the AUV-BS distance parameter, and we derived handover strategies considering the BS motion in the overlapping region. In our simulation, we investigated how the direction and magnitude of BS motion affect the distance between the AUV and the BS. The results showed that the intensity of BS motion, quantified by the WMO sea state code, has a greater impact on distance variability than its direction. We also analyzed how BS motion influences handover decisions. Through this analysis, we derived a metric, denoted as \(|\Delta D_{BA12}|\), to quantify the variability in AUV-BS distance caused by BS motion. When BSs move in the same direction, the variability in \(|\Delta D_{BA12}|\) increases in the overlapping region, whereas opposite movements cause the variability in \(|\Delta D_{BA12}|\) at the start and end points of the path of the AUV. In addition, we analyzed network radius effects on \(|\Delta D_{BA12}|\), finding that larger radii reduce its variability. The simulation results confirmed BS motion and network radius as critical factors in handover decision errors. Notably, errors increase in overlapping regions when the current and target BSs move in the same direction, especially with larger BS motions. Conversely, reducing the network radius lessens these errors. We developed an indicator to assess the impact of BS motion on AUV-BS distance. This comprehensive analysis provides valuable insights for designing effective underwater handovers. Although the architecture for B-UWANs employing mobile nodes has been standardized, the development of corresponding handover technologies to support the mobility of AUVs is still in its early stages. Therefore, the insights and recommendations offered in this paper are poised to significantly contribute to the advancement of handover protocols for B-UWANs, particularly by addressing the dynamic nature of BS positions influenced by maritime conditions. The authors collaborated in developing the main idea of the overall paper. For the analysis of the influence of BS motion on underwater handover, [PERSON] mainly built the simulator and conducted the simulation experiments, as well as investigating several performance metrics. [PERSON]-[PERSON] mainly contributed to modeling the BS motion. The authors also collaborated in analyzing the simulation results and writing this manuscript. All authors have read and agreed to the published version of the manuscript. **Funding:** This work was supported by a grant from the Korea Research Institute for Defense Technology Planning and Advancement (KRIT), funded by the Korean government (DAPA-Defense Acquisition Program Administration) (No. 20-102-B00-007(KRIT-CT-22-085): the technical research for underwater communication mobile network using the surface buoy base station, 2022.