# 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 between the Zones  
**Step 1. Creation of Zone management list for Zone management:** When mobile users move to the external Zone, it is necessary to register the information of the Zone composed of access MECS in the ZMO that manages the Zones in order to support mobility management and task migration of mobile users. To this end, the EMO, which manages the information of the access MECS, transmits its EML to the ZMO preset by the carrier operator. ZMO that receives EML from EMO that manages Zones generates Zone management list (ZML) to efficiently perform mobility management and task migration of mobile users moving between Zones. That is, the ZMO which generates the ZML having the information of the Zone by receiving the EML knows the information of multiple Zones, so that it is possible to provide a continuous service delivery even when the mobile user moves to an external  
Figure 5: ZU message format and example. Zone which does not exist in the tracking area information. Figure 6 shows an example of the ZML generated by the ZMO. The Zone identifier field is a unique identifier for the Zone created by the EMO. The EMO identifier field is a unique identifier of the EMO. Finally, the Zone tracking area field is composed of information on neighboring Zones generated by the ZMO based on the EML received from the EMO to provide continuous service delivery and mobility management to the mobile users moving to the external Zone. In other words, ZMO generates ZML using information from EMO and uses it to generate Zone tracking area information and transmits it for mobile user mobility management between Zones to EMO. Therefore, it is possible to provide continuous service delivery even when mobile users frequently move to other Zones. **Step 2. Movement Indication:** The access MECS periodically broadcasts the AMS message containing information related to the Zone and access MECS, as well as detecting the movement of the mobile user within the Zone in Section 3.1. The mobile user receiving the AMS message can recognize whether the mobile user has moved using the field information in the AMS message. That is, mobile users recognize that they have moved to another Zone by checking the Zone identifier field in the AMS message, which records identification for the Zone managed by EMO. The mobile users who detect their movement transmits the ZU message to the access MECS in order to continuously perform the existing task at the new location. The access MECS that received the ZU message checks the Zone Info field of the ZU message to recognize that it is a movement between Zone and delegates the processing of Zone update to the EMO. The EMO, delegated to handle Zone update, sends ZU message to ZMO in order to support the movement of the mobile user between the external Zones. The ZMO can identify the access MECS where the mobile user was previously located by using the ZML in which the information of the Zones managed by each EMO is recorded. The ZMO, which identifies the access MECS where the mobile user is previously located, performs task migration to the access MECS, where the mobile user is currently located. **Step 3. Path Creation for Task Migration:** When the mobile users receive the AMS message periodically transmitted by the access MECS and then recognize the movement to other Zones, they send the ZU message to the access MECS. The access MECS receiving the ZU Message checks the task migration field of the ZU message and determines whether the mobile user is working from the access MECS that was previously located. The access MECS, which recognizes that mobile users have moved to an external Zone by checking the Zone info field in the ZU message, delegates the processing of the Zone update to the EMO. The EMO, delegated to handle Zone update, supports the movement of the mobile user between the external Zones and transmits the ZU message to the ZMO in order to provide the continuous service delivery.