## 2 Background
### Mobility Management in Future Wireless Networks  
Important improvements are introduced by 5G networks in the wireless network world such as increasing network capacity, enhancing user experience, and supporting wider user applications than previous generations. These applications are grouped under variant categories such as Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communication (URLLC), and Massive Machine-Type Communication (mMTC). Thus, MM is one of the vital aspects of the 5G improvements, which ensures seamless connectivity during users' mobility while crossing different cells or base stations (BSs) [12]. Thus, MM plays a crucial role in coordinating several key functionalities of wireless networks. These functionalities include the following, as illustrated in Figure 1:  
* Attach and Detach Management: To establish a call or activate a data session, the UE initiates the attach procedure toward the network. This process involves registering the UE with the network, obtaining an identity, and negotiating service parameters. While ending a call or deactivating a data session, the UE initiates the detach process to notify the network and release resources. These procedures ensure efficient resource management and enable the network to track the active UEs and maintain service continuity [13]. * Location Management: The UEs location is continuously monitored by MM by the tracking cell associations and periodic signaling. This provides the network with a real-time understanding of the UEs location and activity, which aids efficient resource allocation and service delivery [14]. * Handover Management: When a UE with a Radio Resource Control (RRC) connected state moves from one cell to another, MM seamlessly transfers the ongoing data session (e.g., call, data, etc.) to the new cell. This process ensures a smooth transition and minimizes latency, preventing noticeable disruptions for the user [8]. * Context-Aware Management: As networks develop towards greater intelligence, MM incorporates context-aware management. By using specific information about network conditions, user behavior, and application requirements, MM can prioritize traffic and optimize resource allocation for specific use cases to enhance network performance and user experience [15]. * Network Slicing Management: 5G and future networks introduce network slicing, which virtually divides the physical network into customizable slices that serve specific service requirements. MM facilitates seamless handover between slices, allowing users to switch based on their needs (e.g., high bandwidth for video streaming or low latency for autonomous vehicles) while maintaining connectivity [16]. * Dual Connectivity (DC) Management: DC is an innovative technology that allows UEs to connect to two adjacent cells simultaneously [17]. This can be beneficial in areas with limited coverage or for high data rate requirements. MM plays a crucial role in managing DC cases by efficiently distributing traffic between the two connections, ensuring optimal utilization of available resources, and maximizing network performance. Furthermore, ensuring seamless transitions when UE moves between areas with and without DC support maintain active connections and minimize service disruptions. * Carrier Aggregation (CA) Management: CA allows for UEs to combine multiple frequency bands simultaneously. This effectively increases the overall bandwidth available to the UE, enhancing the data rate [17]. MM also plays a critical role in managing CA where it intelligently selects and combines suitable frequency bands based on network conditions and user requirements, maximizing the benefits of CA. Furthermore, it ensures the aggregated channels are seamlessly transferred to the new cell during the HO process when UE moves between cells, maintaining data rates and minimizing service disruptions. However, 6G networks target a lower latency and higher reliability than 5G to allow for applications like real-time control of robots and haptic feedback in virtual reality [18].