# Mobility Management of Unmanned Aerial Vehicles in Ultra-Dense Heterogeneous Networks
###### Abstract
The data interchange protocols used by UTM and mobile network centers, particularly Allied Telesis Management Framework (AMF), have permitted the confirmation and authorization of UAVs within the zone. Including UAVs in this flexible network will increase the AMF's computational load. The use of UAV-mounted BS (UxNB) to extend the scope range is specified in 3 GPP references. The UxNB may connect to a 5G core as a BS on the ground via a wireless backhaul link. The UxNB can be used in various situations (such as in emergencies, the temporary scope for UEs, and hotspot events) due to its quick setup and vast range of capabilities. When acting as a BS, the UxNBs must be validated by the center setup. Since UAVs have limited power, one condition for utilizing a BS is to consume as little energy as possible. The use of UAVs is limited due to their flying time and energy requirements. In conveyance administrations, for instance, using a single UAV results in a waiting period for the vehicle to return to base. As a result, UAVs should be used in swarm mode. Group management is the most basic requirement for a swarm of UAVs. Group management entails collecting confirmation and guaranteeing secure communication within a group. This research focuses on the HO of UAV communication through wireless communication. A smooth HO is difficult to achieve while using traditional wireless networks. When compared to cellular networks, UAV wireless communications have less communication coverage and a longer HO procedure. The conventional HO technique further assumes that the coverage area for different cells is the same, which is not the case with UAVs due to their varying heights. The HO of UAVs should be more closely and efficiently monitored than that of terrestrial UEs. The use of traditional HO methods and strategies may not be suitable for UAVs. Although numerous relevant arrangements have been discussed throughout the literature, the problem remains unaddressed. Since future mobile networks are expected to be self-sufficient, node mobility forecasting may be a critical technique for optimizing the benefits of UAV systems. A large number of contemporary arrangements follow distance-based assumptions [2; 35]. The objective of this study is to highlight the mobility management of connected UAVs in future mobile networks (5G and 6G). The article covers current research efforts devoted to addressing the inherent difficulties of using UAVs. The main research goal is to answer the most important questions in wireless communications. For example, why is HO difficult for UAVs, even more so during UAV mode when they can move freely in 3D? What are the current solutions to this problem? What are the future research directions in this field? This paper includes an assessment of the most significant practical solutions for resolving these problems. The central issues are outlined, and the recent research is highlighted and discussed. This paper extensively reviews the necessity of integratingUAVs into modern wireless communication networks, providing scholars with abundant knowledge in this field. The remainder of this work is organized as follows. Section 2 provides an overview of the relevant literature. Section 3 highlights important achievements in the field and presents background research information. Section 4 focuses on the research challenges. Section 5 reviews the published works related to this research. Section 6 provides the proposed solutions. Section 7 discusses future research directions. Finally, Section 8 concludes this paper.