# ZONE-Based Multi-Access Edge Computing Scheme for User Device Mobility Management
## 3 Proposed Zone-Based MEC Architecture for User Device Mobility Management
### A Scheme to Support User Mobility Management within the Zone
The access MECS Identifier field is identification information for the access MECS currently located in the mobile user, and this information can be used by the mobile users to detect whether they have moved. The inner group tracking area field represents information grouped into several adjacent access MECSs. This allows mobile users to quickly infer adjacent access MECS, so that it is possible to provide a continuous service even when the mobile user moves. The mobile user who receives the AMS message periodically checks the Zone identifier and the access MECS identifier field to detect his/her movement event. The mobile user who detects the movement sends a Zone Update (ZU) message to the access MECS to continuously perform the same task being performed by the previous MECS in the new location. Upon receiving the ZU message, access MECS performs a migration of existing tasks from the access MECS where the mobile user was previously located. **Step 4. Path Creation for Task Migration:** Mobile users aware of their movements by receiving AMS messages periodically sent by access MECS send ZU messages to access MECS to register with  
Figure 4: AMS message format and example. Figure 3: An example of EML list generated by the EMO. the newly moved Zone. Figure 5 shows the format and example of the ZU message. The task migration field is used to determine whether or not a mobile user is performing the task at the access MECS where it is previously located. The access MECS identifier field indicates the identifier of the access MECS to which the mobile user was previously located. The Zone info field is used to identify whether a mobile user has moved from an internal Zone or an external Zone using the Zone identifier field in the AMS message received from the access MECS. Access MECS that received the ZU message first checks the task migration field of the ZU message to check whether the mobile user needs task migration from the previously located access MECS. When a task migration is required, access MECS performs a task of checking the access MECS identifier of the ZU message to check whether the mobile user has moved in the area it is tracking. If the mobile user moves from the area currently recorded in the access MECS tracked list, the access MECS can identify the previously located access MECS of the mobile user. In other words, access MECS, which checks the access MECS identity field recorded in the ZU message and identifies the access MECS that the mobile user was previously located, transmits a task migration request message to the access MECS where the mobile user was previously located. Access MECS that receives task migration request transmits task in progress to the access MECS where mobile user is currently located. The access MECS, which received task from the access MECS where mobile users were previously located, continues to perform task and provides continuous service to mobile users. That is, the proposed scheme performs the task migration from the access MECS that the mobile user was previously located based on the inner group tracking area information so that it is possible to provide a continuous service even when the mobile user moves. On the other hand, if the access MECS identifier does not exist in the inner group tracking area information of the access MECS, it means that the mobile user moves in the area where the access MECS is not tracking. Therefore, the ZU message is redirected to the EMO managing the access MECS. The EMO receiving the ZU message refers to its EML and transmits a task migration request to the access MECS where the mobile user was previously located. The access MECS that received the task migration request sends the currently performed task to the EMO, and the EMO that received the task transmits to the access MECS where the mobile user is currently located.